UNIT V

ECOSYSTEM STABILITY AND ECOLOGICAL MANAGEMENT

Structure

5.1 Introduction 5.2 Objectives 5.3 Ecosystem stability

5.3.1 Diversity and Stability5.3.2 Functional diversity5.3.3 Concepts of Stability

5.4 Ecology of Plant Invasion5.4.1 Definitions5.4.2 Conditions that lead to invasion5.4.3 Ecology of invasion5.4.4 Impact of invasion5.4.5 Threat to global biodiversity

5.5 Environmental Impact Assessment 5.5.1 Assessment of Environment in India - Background 5.5.2 Environmental Impact Assessment : A Process5.5.3 Environmental Impact Statement : The Documentation 5.5.4 Purpose of EIA

5.6 Ecosystem Restoration5.6.1 Ecosystem health5.6.2 How healthy ecosystems become pathological5.6.3 Ecosystem health and human health5.6.4 Ecosystem restoration5.6.5 Problems with restoration5.6.6 Prevention of ecosystem disruptions

5.7 Ecological Management5.7.1 Ecological management 5.7.2 Current status and threats5.7.3 Biologically achievable management goals5.7.4 Societal factors5.7.5 Establishing management goals5.7.6 Adaptive management5.7.7 A critique of ecological management

5.8 Sustainable development5.8.1 Background

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5.8.2 Definitions5.8.3 Goals5.8.4 Indicators5.8.5 Values5.8.6 Practice5.8.7 So, What Is Sustainable Development?

5.9 Lets sum up5.10 Check your progress : the key5.11 Assignments/ Activities 5.12 References/ Further Readings

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5.1 INTRODUCTION

Man has always inhabited two worlds. One is the ‘natural-world’ of plants, animals, air, water, and soil of which man himself is a part; while other is the ‘built-world’ of social and cultural institutions and artifacts which he created for himself by using science and technology, and political organization. Both the natural and socio-cultural worlds constitute an important part of the environment.

Thus, Environment is a quite comprehensive term that includes not only the areas of air, water, plants, and animals, but also other natural and man-modified features like transportation systems, land use characteristics, community structures, as well as economic stability. In other words, the environment is made up of both biophysical and socio-economic elements. As a result of environmental degradation due to unrestrained industrial and technological progresses and over-exploitation of natural resources; there has been increasing awareness in environmental issues in sustainability and the better management of development in harmony with the environment, in recent decades. Associated with this environmental awareness has been the introduction of new legislation, emanating from national and international agencies, that seeks to influence the relationship between development and the environment.

5.2 OBJECTIVES

The foregoing unit approaches the study of ecology at individual, population, and community levels, mainly being a descriptive approach. The main objectives of this unit are to know the structures, function, management, and sustainable use of ecosystem. The major objectives of present study are :

To understand the structure and function of ecosystem ;

To study the diversity and stability of an ecosystem;

To understand invasive species and their ecology;

To identify thrust areas of ecosystem and their managment;

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The study the environmental impact assessment process and understand its role on the development of country

To explain the sustainable use of nature and natural resources and their development.

5.3 ECOSYSTEM STABILITY

We are at that point in the course where we are switching gears. In last four units, we have focusing on the biological diversity, environmental pollution and their control measures, and conservation strategies for biological wealth. In this unit, we are going to be reading about ecosystem stability and function, perturbation and restoration, invasive plant species and their ecology, and ecological management. We will be reading about environmental impact assessment and sustainable development.

Every ecosystem is subject to perturbations such as climate, nutrient fluctuation, loss of biodiversity, and introduction of exotic species, that can alter ecosystem structure and function. The degree to which ecosystems respond to perturbations depends their ability to withstand perturbation and maintain normal function (resistance) and/ or recover from disturbance (resilience).

It is commonly believed that the more diverse an ecosystem is, the more stable it will be. These two components of stability, in essence, address how a system responds to disturbances and knowledge about them is key to developing ecosystem recovery and restoration efforts. Before we can read about this relationship, however, we need to decide just what diversity really is.

Whittaker [1972] distinguished three types of diversity.

1. Alpha diversity—diversity within a particular area or ecosystem

2. Beta diversity—the change in diversity between ecosystems

3. Gamma diversity—the overall diversity in a landscape comprised of several ecosystems

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Rosenberg et al. [2002] studied microsatellite variation in human beings at several hundred loci. They were able to distinguish five major geographical groupings of populations: Africa, Eurasia, East Asia, America, and Oceania. Of the total diversity in human populations, roughly 10% of the diversity is a result of differences among the different geographical groupings. Diversity within each geographical grouping corresponds to alpha diversity, the total diversity within human beings corresponds to gamma diversity, and the proportion of diversity due to differences among geographical populations (10%) corresponds to beta diversity.

Most analyses for conservation purposes have focused only on species diversity attempting to identify regions with a large number of species. You all probably realize, however, that there are several aspects to diversity :

Number of different species

Relative abundance of different species

Ecological distinctiveness of different species, e.g., functional differentiation

Evolutionary distinctiveness of different species

We also won’t discuss formal definitions of ecological diversity, which are primarily definitions of alpha diversity although they can be generalized to allow partitioning of gamma diversity into its alpha and beta components. These definitions treat all species as equivalent, ignoring aspects of ecological and evolutionary distinctiveness. Until relatively recently, many experimental evaluations of the diversity-stability hypothesis did the same.

5.3.1 DIVERSITY AND STABILITY

Over the past few decades, it has been commonplace for conservationists to appeal to the diversity-stability hypothesis as a component of their arguments for the importance of conserving biological diversity.

Consider, for example, the following passage from Barry Commoner’s book, The Closing Circle : The amount of stress which an ecosystem can absorb before it is driven to collapse is also a result of its various interconnections and their relative speeds of response. The more complex the ecosystem, the more successfully it can resist a stress. Like a net, in which each knot is

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connected to others by several strands, such a fabric can resist collapse better than a simple, unbranched circle of threads – which if cut anywhere breaks down as a whole. Environmental pollution is often a sign that ecological links have been cut and that the ecosystem has been artificially simplified

Principles

Robert MacArthur [2002] proposed measuring the stability of an ecosystem by measuring the number of alternative pathways it contains through which energy can flow. He justified this measure by arguing that an ecosystem with many pathways, representing an abundance of species organized in a complex food web, tends to equilibrate fluctuations in population as predators will switch from less abundant to more abundant prey species, lowering population densities of the more common and allowing the density of the less common to increase.

There are six reasons for thinking the hypothesis to be true:

1. Evidence from mathematical models suggests that those with few species are inherently unstable.

2. Laboratory experiments are consistent with the mathematical models.

3. Habitats on small islands are more susceptible to invasion than are those on continents.

4. Less diverse habitats of cultivated or planted land are more susceptible to invasion than undisturbed habitat.

5. Highly diverse tropical forest ecosystems are relatively resistant to pest invasion.

6. Orchard spraying, which simplifies ecological relationships, tends to increase the likelihood of severe oscillations in pest populations.

In 1975, Daniel Goodman summarized the mounting evidence against the diversity stability hypothesis by responding to each of Elton’s arguments for it.

1,2 Models of more complex communities showed just the opposite of what Elton asserted. The more species that interact the less likely the system is to be stable.

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3 The data suggesting vulnerability of islands to invasions by pest species may result from accidents of distribution or other special characteristics of islands.

4,6 Crops and orchard tree planted in pure stands do not represent equilibrium low diversity systems. It is difficult to find evidence that naturally low diversity communities are more susceptible to invasion than naturally high diversity communities.

5 The tropical biota is so diverse and complex that large fluctuations might go unnoticed. Furthermore, there is evidence that even highly diverse systems can be dramatically altered by invaders, e.g., the impact of the crown-of-thorns starfish on coral reefs.

Empirical results

Tilman and Downing [14] suggest that primary productivity in more diverse plant communities is more resistant to, and recovers more fully from, a major drought.

207 plots of prairie grasslands differing in species richness from 1 to 26.

Measured resistance as relative rate of community biomass change from 1986, the year before a drought, to 1988, the peak of the drought.

Drought resistance is an increasing function of community diversity.

Saturates at about 10–15 species.

More diverse communities are more resistant than less diverse communities, but they don’t have to be very diverse.

Recent results on the relationship between bacterial species diversity and community respiration (a measure of total microbial activity) show that there are diminishing returns as the number of species in the bacterial community increases [1]. The strong diminishing returns associated with increases in species diversity are likely to be a general feature of relationships between ecosystem processes and species richness.

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In a similar experiment Tilman et al. [1996] found that plant cover is an increasing function of species richness and lower concentrations of inorganic soil nitrogen, presumably because of greater nitrogen uptake in more diverse communities. Experiments of van der Heijden et al., (1998) on mycorrhizal diversity suggest that plant species composition and community structure are more sensitive to the present or absence of particular mycorrhizal associates when the diversity of mycorrhizal fungi is low. Similarly, plant species diversity, nutrient capture, and productivity are increasing functions of mycorrhizal diversity.

But there are two possible explanations for patterns like these:

1. More diverse communities could increase the chances that at least one species within them is highly productive.

2. More diverse communities may be able to tap resources more effectively because the differ in strategies for resource acquisition.

Cardinale et al. [2006] perform a meta-analysis of 111 field, greenhouse, and laboratory studies that manipulated species diversity to determine its effect on abundance and biomass. They found that

Decreasing diversity is, on average, associated with decreased abundance, decreased biomass, or both.

The standing biomass of the richest polyculture tends to be no different from that of the most productive monoculture.

“Collectively [their] analyses suggest that the average species loss does indeed affect the functioning of a wide variety of organisms and ecosystems, but the magnitude of these effects is ultimately determined by the identity of species that are going extinct”. Using a somewhat different approach Grace et al. reach a similar conclusion: “[T]he influence of small-scale diversity on productivity in natural systems is a weak force, both in absolute terms and relative to the effects of other controls on productivity”.

5.3.2 FUNCTIONAL DIVERSITY

Diaz and Cabido [2001] point out that experiment like those just described focus only on the number of species present, not on the functions, they play in

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an ecosystem. They summarize evidence from a variety of studies suggesting that ecosystem processes depend on functional diversity far more strongly than on species diversity per se. They suggest two plausible explanations:

Functional redundancy

Two or more species in a particular ecosystem may play essentially the same role in ecosystem processes. It may for example, make relatively little difference to the nitrogen dynamics which particular species of legumes are present, only that there are some nitrogen-fixing plants present. The loss of species with similar functional effects should have relatively little effect on ecosystem processes.

Functional insurance

The more divergent species in an ecosystem are with respect to their influence on ecosystem processes, the smaller the number required to buffer an ecosystem against change. Species with similar functional effects that differ in functional response may buffer ecosystems against externally imposed change because the species that influence each ecosystem response may respond differently.

5.3.3 CONCEPTS OF STABILITY

Part of the problem here is that it’s not entirely clear what we mean by stability, nor what aspect of diversity we are considering.

Are we concerned only with the number of species in the community and its relation to stability, are we concerned with how evenness relates to stability, or are we concerned with some combination of both? Work I am aware of that considers the problem focuses only on species diversity, i.e., the number of species present, and only recently has begun to consider the degree of functional diversity represented.

– In one sense this may be legitimate. After all, part of the reason conservationists have invoked the diversity-stability hypothesis is to justify concern about the loss of individual species.

– We may also be missing something important. If other aspects of diversity play an important role in the structure and function of ecosystems, a focus on the number of species alone may blind us to

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the role that evenness plays in the ability of ecosystems to respond to changes in energy and nutrient inputs.

Various meanings depending on context. There are at least three ways in which stability might be defined.

1. Lack of change

2. Ability to return quickly to a previous state

3. Not going extinct

Some ecologists use more specific terms :

1. Constancy

“Tendency of an ecosystem to maintain homeostasis (i.e. remain constant over time)” Homeostasis = equilibrium. This is the definition most people use when talking about ecological “stability” i.e. remains at equilibrium.

What remains at equilibrium? Examples: No long-term loss of:

Biomass production

Species composition

Population structure

Resources: organic matter, moisture, nutrients, soil characteristics

– The ability of a community to resist changes in composition and abundance in response to disturbance. Not a particularly useful concept of stability for conservationists because.

– Few, if any, ecosystems could be described as constant.

– Even those that have powerful mechanisms for reacting to environmental fluctuations do so through internal changes that return the system as quickly as possible to a stable state. But these involve responses and changes. It seems better to regard them as examples of resiliency than of constancy.

2. Resilience

The ability of a community to return to a prior state (equilibrium) after disturbance.

Elasticity : how quickly community returns to equilibrium after disturbance

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Amplitude : how much disturbance community can tolerate and still return to equilibrium

Resistance : the force needed to change the community

– The ability of a community to return to its pre-disturbance characteristics after changes induced by a disturbance. Resiliency corresponds to stability the way it is studied in mathematical models. Are deviations from equilibrium reduced with time (stable) or amplified with time (unstable)? Still, it has little applicability to actual ecosystems. It measures a system’s tendency to return to a single stable point, but

– Many ecological systems appear to have multiple stable points. If disturbance remains below a particular threshold, it will return to its predisturbance configuration. If it exceeds that threshold, it may move to a new configuration.

– Furthermore, most ecological systems change not only in response to disturbance but also in response to natural, successional change.

– There is little evidence that ecological communities ever represent an equilibrium configuration from which it would make sense to study perturbations.

Constancy and resiliency have this in common: both focus on species persistence and abundance as measures of stability.

3. Persistence

Not going extinct. Usually refers to populations of endangered species, as in “the population is stable”.

4. Dynamic stability

– A system is dynamically stable if its future states are determined largely by its own current state, with little or no reference to outside influences. In many ways this seems to correspond with our intuitive notions of stability and to make sense of the relationship between diversity and stability.

– Recall the quote from Commoner: “The more complex the ecosystem, the more successfully it can resist a stress.”

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– A system that is dynamically stable is one that is relatively immune to disturbance. A rapidly spinning gyroscope is dynamically stable because the gyroscopic forces that it generates resist external forces that would alter is plane of rotation.

– It reflects our hope that stable systems should be able to maintain themselves without human intervention.

– A diverse biological system is more likely to be dynamically stable than one that is not diverse because in diverse communities biotic interactions may often play a larger role in a species’ success than its interactions with the physical environment. To the extent that changes in the system are driven by biotic interactions, it is dynamically stable, since characteristics of the system itself are determining its future state.

Ives and Carpenter (2007) suggest a different approach to understanding community stability (Figure 5.1).

– Alternative stable states

– Non-point attractors

– Pulse perturbations

– Press perturbations

– Extinctions

– Invasions

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Figure 5.1: Types of stability, perturbations, and community responses. [From Ives and Carpenter (2007)].

Their approach strikes as quite useful, first because it emphasizes that systems move to a region different from the one from which they were perturbed and second because it reminds us that things other than diversity, like the frequency and character of perturbation, may affect the stability of ecosystems.

Biological integrity

Biological integrity refers to a system’s wholeness, including presence of all appropriate elements and occurrence of all processes at appropriate rates.

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1. What are “appropriate elements”?

2. What are “appropriate rates” of processes?

By definition, naturally evolved assemblages possess integrity but random assemblages do not. Therefore, provides justification for management focusing on native species rather than introduced ones. This seems like the logical fallacy of affirming the consequent, but

– Species composition of lakes exposed to nutrient enrichment or acidification responds more quickly and recovers more slowly than processes like primary production, respiration, and nutrient cycling.

– Shifts in biotic composition do not necessarily lead to changes in process rates.

– Angermeier and Karr suggest that these observations means a focus on integrity rather than diversity makes sense. To me it makes more sense to conclude that species changes are a more sensitive indicator of what is going on than process changes.

– Loss of native species from a system is truly “a canary in the mine,” a warning of process changes that may have consequences much larger than we suspect.

5.4 ECOLOGY OF PLANT INVASION With increased trade and travel, invasions by introduced vascular plants are becoming commonplace and are widely recognized as one of the most serious threats to biodiversity and to economies. Introduced plants can have wide-ranging negative effects on ecosystems. These include alterations to the physical structure of habitats, nutrient cycling, fertility and productivity, hydrological regimes, and food webs. All of these alterations would likely negatively impact local subsistence economies greatly. However, not all introduced plants are serious threats. Roughly 1% of species that become established in natural areas become a serious problem. Therefore, understanding of patterns of species richness is important to predict and limit plant invasions.

5.4.1 DEFINITIONS

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Invasive species is a phrase with several definitions. The first definition expresses the phrase in terms of non-indigenous species (e.g. plants or animals) that adversely affect the habitats they invade economically, environmentally or ecologically. It has been used in this sense by government organizations as well as conservation groups such as the IUCN (International Union for Conservation of Nature).

The second definition broadens the boundaries to include both native and non-native species that heavily colonize a particular habitat. The third definition is an expansion of the first and defines an invasive species as a widespread non-indigenous species. This last definition is arguably too broad as not all non-indigenous species necessarily have an adverse effect on their adopted environment. An example of this broader use would include the claim that the common goldfish (Carassius auratus) is invasive. Although it is common outside its range globally, it almost never appears in harmful densities.

Because of the ambiguity of its definition, the phrase invasive species is often criticized as an imprecise term within the field of ecology. This article concerns the first two definitions; for the third, see introduced species.

Stages : In an attempt to avoid the ambiguous, subjective, and pejorative vocabulary that so often accompanies discussion of invasive species even in scientific papers, Colautti and MacIsaac have proposed a new nomenclature system based on biogeography rather than on taxa.

Stage Characteristic

0 Propagules residing in a donor region

I Traveling

II Introduced

III Localized and numerically rare

IVa Widespread but rare

IVb Localized but dominant

V Widespread and dominant

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By removing taxonomy, human health, and economic factors from consideration, this model focuses only on ecological factors. The model evaluates individual populations, and not entire species. This model does not attribute detrimentally to invasive species and beneficially to native species. It merely classifies a species in a particular location based on its growth patterns in that particular microenvironment. This model could be applied equally to indigenous and to non-native species.

5.4.2 CONDITIONS THAT LEAD TO INVASION

Scientists propose several mechanisms to explain invasive species, including species-based mechanisms and ecosystem-based mechanisms. It is most likely a combination of several mechanisms that cause an invasive situation to occur, since most introduced plants and animals do not become invasive.

Species-based mechanisms

Species-based characteristics focus on competition. While all species compete to survive, invasive species appear to have specific traits or combinations of specific traits that allow them to outcompete native species. Sometimes they just have the ability to grow and reproduce more rapidly than native species; other times it's more complex, involving a multiplex of traits and interactions.

Studies seem to indicate that certain traits mark a species as potentially invasive. One study found that of a list of invasive and noninvasive species, 86% of the invasive species could be identified from the traits alone. Another study found that invasive species tended only to have a small subset of the invasive traits and that many of these invasive traits were found in non-invasive species as well indicating that invasiveness involves complex interaction not easily categorized. Common invasive species traits include:

The ability to reproduce both asexually as well as sexually

Fast growth

Rapid reproduction

High dispersal ability

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Phenotypic plasticity (the ability to alter one’s growth form to suit current conditions)

Tolerance of a wide range of environmental conditions (generalist)

Ability to live off of a wide range of food types (generalist)

Association with humans

Other successful invasions

Typically an introduced species must survive at low population densities before it becomes invasive in a new location. At low population densities, it can be difficult for the introduced species to reproduce and maintain itself in a new location, so a species might be transported to a location a number of times before it become established. Repeated patterns of human movement from one location to another, such as ships sailing to and from ports or cars driving up and down highways, allow for species to have multiple opportunities for establishment (also known as a high propagule pressure).

An introduced species might become invasive if it can out-compete native species for resources such as nutrients, light, physical space, water or food. If these species evolved under great competition or predation, the new environment may allow them to proliferate quickly. Ecosystems in which all available resources are being used to their fullest capacity by native species can be modeled as zero-sum systems, where any gain for the invader is a loss for the native. However, such unilateral competitive superiority (and extinction of native species with increased populations of the invader) is not the rule. Invasive species often coexist with native species for an extended time, and gradually the superior competitive ability of an invasive species becomes apparent as its population grows larger and denser and it adapts to its new location.

An invasive species might be able to use resources previously unavailable to native species, such as deep water sources accessed by a long taproot, or an ability to live on previously uninhabited soil types. For example, Barbed Goatgrass (Aegilops triuncialis) was introduced to California on serpentine soils, which have low water-retention, low nutrient levels, a high Mg/Ca ratio, and possible heavy metal toxicity. Plant populations on these soils tend to show low density, but goatgrass can form dense stands on these soils crowding out native species that have not adapted well to growing on serpentine soils.

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Facilitation is the mechanism by which some species can alter their environment using chemicals or manipulating abiotic factors, allowing the species to thrive while making the environment less favorable to other species with which it competes. One such facilitative mechanism is allelopathy, also known as chemical competition or interference competition. In allelopathy a plant will secrete chemicals which make the surrounding soil uninhabitable, or at least inhibitory, to competing species.

One example of this is the knapweed Centaurea diffusa. This Eastern European weed has spread its way through the western United States. Experiments show that 8-Hydroxyquinoline, a chemical produced at the root of C. diffusa, has a negative effect only on plants that have not co-evolved with C. diffusa. Such co-evolved native plants have also evolved defenses, and C. diffusa does not appear in its native habitat to be an overwhelmingly successful competitor. This shows how difficult it can be to predict if a species will be invasive just from looking at its behavior in its native habitat, and demonstrates the potential for novel weapons to aid in invasiveness.

Changes in fire regimes are another form of facilitation. Bromus tectorum, originally from Eurasia, is highly fire-adapted. It not only spreads rapidly after burning, but actually increases the frequency and intensity (heat) of fires, by providing large amounts of dry detritus during the dry fire season in western North America. In areas where it is widespread, it has altered the local fire regime so much that native plants cannot survive the frequent fires, allowing B. tectorum to further extend and maintain dominance in its introduced range.

Facilitation also occurs when one species physically modifies a habitat and that modification is advantageous to other species. For example, zebra mussels increase habitat complexity on lake floors providing crevases in which invertebrates live. This increase in complexity, together with the nutrition provided by the waste products of mussel filter-feeding increases the density and diversity of benthic invertebrate communities.

Ecosystem-based mechanisms

In ecosystems, the amount of available resources and the extent to which those resources are utilized by organisms determines the effects of additional species on the ecosystem. In stable ecosystems, equilibrium exists in the utilization of available resources. These mechanisms describe a situation in

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which the ecosystem has suffered a disturbance which changes the fundamental nature of the ecosystem. When changes occur in an ecosystem, like forest fires in an area, normal succession would favor certain native grasses and forbs. With the introduction of a species that can multiply and spread faster than the native species, the balance is changed and the resources that would have been used by the native species are now utilized by an invader. This impacts the ecosystem and changes its composition of organisms and their use of available resources. Nitrogen and phosphorus are often the limiting factors in these situations.

Every species has a role to play in its native ecosystem; some species fill large and varied roles while others are highly specialized. These roles are known as niches. Some invading species are able to fill niches that are not utilized by native species, and they also can create niches that did not exist.

When changes occur to ecosystems, conditions change that impact the dynamics of species interaction and niche development. This can cause once rare species to replace other species, because they now can utilize greater available resources that did not exist before, an example would be the edge effect. The changes can favor the expansion of a species that would not have been able to colonize areas and niches that did not exist before.

5.4.3 ECOLOGY OF INVASION

Although an invasive species is often defined as an introduced species that has spread widely and causes harm, some species native to a particular area can, under the influence of natural events such as long-term rainfall changes or human modifications to the habitat, increase in numbers and become invasive.

All species go through changes in population numbers, in many cases accompanied by expansion or contraction of range. Human landscape alterations are especially significant. This anthropogenic alteration of an environment may enable the expansion of a species into a geographical area where it had not been seen before and thus that species could be described as invasive. In essence, one must define "native" with care, as it refers to some natural geographic range of a species, and is not coincident with human political boundaries. Whether noticed increases in population numbers and expanding geographical ranges is sufficient reason to regard a native species

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as "invasive" requires a broad definition of the term but some native species in disrupted ecosystems can spread widely and cause harm and in that sense become invasive. For example, the Monterey Cypress is an endangered endemic naturally occurring only in two small stands in California. They are being exterminated as exotic invasive species less than 50 miles (80 km) from their native home.

Traits of invaded ecosystems

In 1958, Charles S. Elton argued that ecosystems with higher species diversity were less subject to invasive species because of fewer available niches. Since then, other ecologists have pointed to highly diverse, but heavily invaded ecosystems and have argued that ecosystems with high species diversity seem to be more susceptible to invasion. This debate seems largely to hinge on the spatial scale at which invasion studies are performed, and the issue of how diversity affects community susceptibility to invasion remains unresolved. Small-scale studies tend to show a negative relationship between diversity and invasion, while large-scale studies tend to show a positive relationship. The latter result may be an artifact of invasive or non-native species capitalizing on increased resource availability and weaker overall species interactions that are more common when larger samples are considered.

Invasion is more likely if an ecosystem is similar to the one in which the potential invader evolved. Island ecosystems may be prone to invasion because their species are “naïve” and have faced few strong competitors and predators throughout their existence, or because their distance from colonizing species populations makes them more likely to have “open” niches. An example of this phenomenon is the decimation of the native bird populations on Guam by the invasive brown tree snake. Alternately, invaded ecosystems may lack the natural competitors and predators that keep introduced species in check in their native ecosystems, a point that is also seen in the Guam example. Lastly, invaded ecosystems have often experienced disturbance, usually human-induced. This disturbance may give invasive species, which are not otherwise co-evolved with the ecosystem, a chance to establish themselves with less competition from more adapted species.

Vectors

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Non-native species have many vectors, including many biogenic ones, but most species considered "invasive" are associated with human activity. Natural range extensions are common in many species, but the rate and magnitude of human-mediated extensions in these species tend to be much larger than natural extensions, and the distances that species can travel to colonize are also often much greater with human agency.

One of the earliest human influenced introductions involves prehistoric humans introducing the Pacific rat (Rattus exulans) to Polynesia. Today, non-native species come from horticultural plants either in the form of the plants themselves or animals and seeds carried with them, and from animals and plants released through the pet trade. Invasive species also come from organisms stowed away on every type of transport vehicle. For example, ballast water taken up at sea and released in port is a major source of exotic marine life. The invasive freshwater zebra mussels, native to the Black, Caspian and Azov seas, were probably transported to the Great Lakes via ballast water from a transoceanic vessel. The arrival of invasive propagules to a new site is a function of the site's invasibility.

Species have also been introduced intentionally. For example, to feel more "at home", American colonists formed "Acclimation Societies" that repeatedly released birds that were native to Europe until they finally established along the east coast of North America.

Economics play a major role in exotic species introduction. The scarcity and demand for the valuable Chinese mitten crab is one explanation for the possible intentional release of the species in foreign waters.

5.4.4 IMPACT OF INVASION

Ecological impacts

Biological species invasions alter ecosystems in a multitude of ways. Worldwide, an estimated 80% of endangered species could suffer losses by competition with, or predation by, invasive species. Pimentel also reports that introduced species, such as corn, wheat, rice, cattle, and poultry, provide more than 98% of the U.S. food system at a value of approximately $800 billion per year. As highly adaptable and generalized species are

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introduced to environments already impacted by human activities, some native species may be put at a disadvantage to survive while other species survival is enhanced.

Land clearing and human habitation put significant pressure on local species. This disturbed habitat is prone to invasions that can have adverse effects on local ecosystems, changing ecosystem functions. A species of wetland plant known as ʻaeae in Hawaii (the indigenous Bacopa monnieri) is regarded as a pest species in artificially manipulated water bird refuges because it quickly covers shallow mudflats established for endangered Hawaiian stilt (Himantopus mexicanus knudseni), making these undesirable feeding areas for the birds.

Multiple successive introductions of different nonnative species can have interactive effects; the introduction of a second non-native species can enable the first invasive species to flourish. Examples of this are the introductions of the amethyst gem clam (Gemma gemma) and the European green crab (Carcinus maenas). The gem clam was introduced into California's Bodega Harbor from the East Coast of the United States a century ago. It had been found in small quantities in the harbor but had never displaced the native clam species (Nutricola spp.). In the mid 1990s, the introduction of the European green crab, found to prey preferentially on the native clams, resulted in a decline of the native clams and an increase of the introduced clam populations.

In the Waterberg region of South Africa, cattle grazing over the past six centuries has allowed invasive scrub and small trees to displace much of the original grassland, resulting in a massive reduction in forage for native bovids and other grazers. Since the 1970s large scale efforts have been underway to reduce invasive species; partial success has led to re-establishment of many species that had dwindled or left the region. Examples of these species are giraffe, Blue Wildebeest, impala, kudu and White Rhino.

Invasive species can change the functions of ecosystems. For example invasive plants can alter the fire regime (cheatgrass, Bromus tectorum), nutrient cycling (smooth cordgrass Spartina alterniflora), and hydrology (Tamarix) in native ecosystems. Invasive species that are closely related with rare native species have the potential to hybridize with the native species. Harmful effects of hybridization have led to a decline and even extinction of native species. For example, hybridization with introduced cordgrass, Spartina

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alterniflora, threatens the existence of California cordgrass (Spartina foliosa) in San Francisco Bay.

Genetic pollution

Natural, wild species can be threatened with extinction through the process of genetic pollution. Genetic pollution is uncontrolled hybridization and introgression which leads to homogenization or replacement of local genotypes as a result of either a numerical or fitness advantage of the introduced species. Genetic pollution can bring about a form of extinction either through purposeful introduction or through habitat modification, bringing previously isolated species into contact. These phenomena can be especially detrimental for rare species coming into contact with more abundant ones where the abundant ones can interbreed with them, creating hybrids and swamping the entire rarer gene pool, thus driving the native species to extinction. Attention has to be focused on the extent of this problem, it is not always apparent from morphological observations alone. Some degree of gene flow may be a normal, evolutionarily constructive process, and all constellations of genes and genotypes cannot be preserved. However, hybridization with or without introgression may, nevertheless, threaten a rare species' existence.

Economic impacts

Benefits

Often overlooked, economic benefits from so-called "invasive" species should also be accounted. The wide range of benefits from many "invasives" is both well-documented and under-reported. Asian oysters, for example, are better at filtering out water pollutants than native oysters. They also grow faster and withstand disease better than natives. Biologists are currently considering releasing the mollusk in the Chesapeake Bay to help restore oyster stocks and clean up the bay's pollution. A recent study by the Johns Hopkins School of Public Health found the Asian oyster could significantly benefit the bay's deteriorating water quality.

Non-native species can become such a common part of an environment, culture, and even diet that little thought is given to their geographic origin. For example, soybeans, kiwi fruit, wheat and all livestock except the llama and the

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turkey are non-native species to North America. Collectively, non-native crops and livestock comprise 98% of US food. These and other benefits from non-natives are so vast that, according to the Congressional Research Service, they probably exceed the costs.

Costs

Economic costs from invasive species can be separated into direct costs through production loss in agriculture and forestry, and management costs of invasive species. Estimated damage and control cost of invasive species in the U.S. alone amount to more than $138 billion annually. In addition to these costs, economic losses can occur through loss of recreational and tourism revenues. Economic costs of invasions, when calculated as production loss and management costs, are low because they do not usually consider environmental damages. If monetary values could be assigned to the extinction of species, loss in biodiversity, and loss of ecosystem services, costs from impacts of invasive species would drastically increase. The following examples from different sectors of the economy demonstrate the impact of biological invasions.

Agriculture

Weeds cause an overall reduction in yield, though they often provide essential nutrients for subsistence farmers. Weeds can have other useful purposes: some deep-rooted weeds can "mine" nutrients from the subsoil and bring them to the topsoil, while others provide habitat for beneficial insects and/or provide alternative foods for pest species. Many weed species are accidental introductions with crop seeds and imported plant material. Many introduced weeds in pastures compete with native forage plants, are toxic (e.g., Leafy Spurge, Euphorbia esula) to young cattle (older animals will avoid them) or non-palatable because of thorns and spines (e.g., Yellow Starthistle, Centaurea solstitialis). Forage loss from invasive weeds on pastures amounts to nearly $1 billion in the U.S. alone. A decline in pollinator services and loss of fruit production has been observed to cause the infection of honey bees (Apis mellifera another invasive species to the Americas) by the invasive varroa mite. Introduced rodents (rats, Rattus rattus and R. norvegicus) have become serious pests on farms destroying stored grains.

In many cases, one could consider the over-abundant invasive plant species as a ready source of biomass in the perspective of biogas production.

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Forestry

The unintentional introduction of forest pest species and plant pathogens can change forest ecology and negatively impact timber industry. The Asian long-horned beetle (Anoplophora glabripennis) was first introduced into the U.S. in 1996 and is expected to infect and damage millions of acres of hardwood trees. Thirty million dollars have already been spent in attempts to eradicate this pest and protect millions of trees in the affected regions.

The woolly adelgid inflicts damage on old growth spruce fir forests and negatively impacts the Christmas tree industry. The chestnut blight fungus (Cryphonectria parasitica) and Dutch elm disease (Ophiostoma novo-ulmi) are two plant pathogens with serious impacts on forest health.

Tourism and recreation

Invasive species can have impacts on recreational activities such as fishing, hunting, hiking, wildlife viewing, and water-based recreation. They negatively affect a wide array of environmental attributes that are important to support recreation, including but not limited to water quality and quantity, plant and animal diversity, and species abundance. Eiswerth goes on to say that "very little research has been performed to estimate the corresponding economic losses at spatial scales such as regions, states, and watersheds." Eurasian Watermilfoil (Myriophyllum spicatum) in parts of the US, fill lakes with plants making fishing and boating difficult.

Health impacts

An increasing threat of exotic diseases exists because of increased transportation and encroachment of humans into previously remote ecosystems. This can lead to new associations between a disease and a human host (e.g., AIDS virus). Introduced birds (e.g. pigeons), rodents and insects (e.g. mosquitoes, fleas, lice and tsetse fly) can serve as vectors and reservoirs of human diseases. The introduced Chinese mitten crabs are carriers of the Asian lung fluke. Throughout recorded history epidemics of human diseases such as malaria, yellow fever, typhus, and bubonic plague have been associated with these vectors. A recent example of an introduced disease is the spread of the West Nile virus across North America resulting in

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the deaths of humans, birds, mammals, and reptiles. Waterborne disease agents, such as Cholera bacteria (Vibrio cholerae), and causative agents of harmful algal blooms are often transported via ballast water. The full range of impacts of invasive species and their control goes beyond immediate effects and can have long term public health implications. For instance, pesticides applied to treat a particular pest species could pollute soil and surface water.

5.4.5 THREAT TO GLOBAL BIODIVERSITY

Biotic invasion is one of the five top drivers for global biodiversity loss and is increasing because of tourism and globalization. It poses a particular risk to inadequately regulated fresh water systems, though quarantines and ballast water rules have improved the situation.

5.5 ENVIRONMENTAL IMPACT ASSESSMENT

Environmental Impact Assessment (EIA) is an important management tool for ensuring optimal use of natural resources for sustainable development. A beginning in this direction was made in our country with the impact assessment of river valley projects in 1978-79 and the scope has subsequently been enhanced to cover other developmental sectors such as industries, thermal power projects, mining schemes etc. To facilitate collection of environmental data and preparation of management plans, guidelines have been evolved and circulated to the concerned Central and State Government Departments. EIA has now been made mandatory under the Environmental (Protection Act, 1986 for 29 categories of developmental activities involving investments of Rs. 50 crores and above.

Environmental Impact Assessment (EIA) is a relatively new planning and decision making tool first enshrined in the United States in the National Environmental Policy Act of 1969. It is a formal study process used to predict the environmental consequences of any development project. EIA thus ensures that the potential problems are foreseen and addressed at an early stage in project planning and design.

Environmental Assessment is taken up in this exercise as a rapid assessment technique for determining the current status of the environment and identifying impact of critical activities on environmental parameters. Based on this

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analysis we can draw up an Environmental Management Plan that would ensure impact monitoring and mitigation planning.

Environmental Assessment enables us in carrying out Environmental Cost-Benefit Analysis of projects at an initial stage. It is thus a pre-cursor to detailed analysis of environmental impacts, which are taken up only if a need for the same is established. It gives a view of the actors involved in the `development-environment linkages. This is required in view of the fact that the community at large is always at a loss in terms of deterioration of living environment that accompanies industrial development. Based on Environmental Assessment, the regulatory measures can be identified and the roles of concerned agencies defined for achieving more efficient environmental management.

In view of the fact that development is an ever growing process, its impact on the environment is also ever increasing, leading to rapid deterioration in environmental conditions. As such Environmental Assessment provides a rational approach to sustainable development.

Extensively developed rapid assessment techniques often avoid carrying out of detailed studies which need more resources in terms of time and money. This exercise is an attempt in developing an approach to Environmental Assessment technique, primarily for industrial townships.

5.5.1 ASSESSMENT OF ENVIRONMENT IN INDIA - BACKGROUND

Environmental Impact Assessment (EIA) may be defined as a formal process used to predict the environmental consequences of any development project. EIA thus ensures that the potential problems are foreseen and addressed at an early stage in the projects planning and design.

The phrase `Environmental Impact Assessment comes from Sec. 102 (2) of the National Environmental Policy Act (NEPA), 1969, USA. Some rudiments of EIA are implicit even in early examples of environmental legislation. Napoleon in 1910 issued a decree which divided noxious occupations into categories: those which must be far removed from habitations, those which may be permitted on the outskirts of towns, and those which can be tolerated even close to habitations, having regard to the importance of the work and the importance of the surrounding dwellings.

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In India, the environmental action formally started with the participation of late Smt. Indira Gandhi in the UN Conference on Human Environment in Stockholm in 1972. A National Committee on Environmental Planning & Coordination (NCEPC) was established to be the apex body in the Department of Science and Technology. The term `Environment figured for the first time in the Fourth Five Year Plan (1969-74) which recorded that `harmonious development is possible only on the basis of a comprehensive appraisal of environmental issues. The Tiwari Committee (Committee on Review of Legislative Measures and Administrative Measures), in its report in 1980, recommended creation of a Department of Environment as a nodal agency to ensure environmental protection, to carry out environmental impact studies of proposed development projects, and to have administrative responsibility for pollution monitoring and control. The department came into being in 1980 within the Ministry of Science and Technology under the charge of the then Prime Minister. In 1989 the subjects of wildlife and forestry were added to the list and a new Ministry of Environment and Forests was created with the Prime Minister holding its charge. Since its inception the Department (under the Ministry) has issued various guidelines on EIA for various projects.

EIA, in brief, extrapolates from scientific knowledge to assess the problem consequences of some human interventions on nature. Although EIA uses the techniques of science, it differs from ordinary scientific inquiry, because it is dealing with events which have not yet occurred, may not occur, and whose chances of occurrence may be changed by the very statement that they may occur.

Some measures are required to be taken in the future to reduce the anticipated environmental degradation. Before starting a major project, it is essential to assess the present environment without the project, and the likely impact of the project on the environment, when it is completed. Therefore, an Environment Impact Assessment has to be made before starting a project. For analysis of environmental impacts, many professions and disciplines have to be involved. Like economic and engineering feasibility studies, Environmental Impact Assessment is a management tool for officials and managers who make important decisions about major development projects. The Environmental Impact Assessment should have the following objectives:

i. Predict environmental impact of projects ii. Find ways and means to reduce adverse impacts

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iii. Shape project to suit local environment iv. Present the predictions and options to the decision-makers

The EIA statement should cover brief description of project, brief description of existing environment, likely impact of project, the mitigation and protection measures, consideration of alternatives, and summary with conclusions.

5.5.2 ENVIRONMENTAL IMPACT ASSESSMENT : A PROCESS

In essence, EIA is a process, a systematic process that examines the environmental consequences – positive or negative – of development actions in advance. Unlike other mechanisms for environmental protection; here, in EIA, the emphasis is on prevention. After an EIA analysis, the precautionary and polluter pays principles is to be applied to prevent, limit or require strict liability or insurance coverage to a project, based on its likely harms. No doubt planners have traditionally assessed the impacts of developments on the environment, but invariably not in the systematic, holistic and multidisciplinary way as required by EIA. The EIA process (or methodology) involves a number of steps which are briefly described as under :

Project screening : It narrows the application of EIA to those projects that may have significant environmental impacts. It is the stage when planners through a preliminary study decide whether to conduct a comprehensive environmental impact assessment study or not. As an aid, the World Bank has placed all the projects in four different categories on the basis of the potential environmental impacts. Large water resources developmental projects, highway projects, thermal power projects, petrochemical and fertilizer projects, mining projects and residential construction projects are some of the examples for which comprehensive EIA studies have to be conducted for identifying the significant environmental impacts, particularly the negative ones. Such projects are screened off right in the beginning of EIA studies.

Scoping : It is focused primarily on determining/ identifying, at an early stage, a project’s specific, significant issues and impacts which are to be addressed/ assessed.

Consideration of Alternatives : This stage seeks to ensure that the proponent (or promoter) has also considered other feasible approaches,

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including alternative projects locations, scales, processes, layouts, operating conditions, and the “no action” option.

Description of the Projects/ Development Action : it seeks a clarification of the purpose and rationale of the projects, and an understanding of its various characteristics, such as stages of development, location and processes.

Description of the Environmental Baseline : it includes the establishment of both the present and future state of the environment, in the absence of the projects, taking into account the changes resulting from natural events and from other human activities.

Identification of key Impacts : This step bring together the previous steps with the aims of ensuring that all the potentially significant environmental impacts (positive and negative) are identified and taken into account in the process.

The prediction of Impacts : this step aims to identify the magnitude and other dimensions of identified change in the environment with a projects/ activity, by comparison with the situation without that project/ activity.

Evaluation and Assessment of Significance : this seeks to assess the relative significance of the predicted impacts to allow a focus on key adverse impacts.

Mitigation : it involves the introduction of measures to avoid, reduce, remedy or compensate for any significant adverse impacts.

Public Consultation and Participation : it aims to assure the quality, comprehensiveness and effectiveness of the EIA, as well as to ensure that the public’s views are adequately taken into consideration in the decision-making process.

EIS Presentation : the environmental impact statement (EIS) presentation is a vital step in the process. If done badly, much good work in the EIA may be negated.

Review : it involves a systematic appraisal of the quality of the EIS, as a contribution to the decision-making process.

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Decision-Making : decision-making on the projects involves a consideration by the relevant authority of the EIS (including consultation response) together with other material considerations.

Post-decision Monitoring : it involves the recording of outcomes associated with development impacts, after a decision to proceed. It can contribute to effective projects management.

Auditing : it follows from monitoring. It can involve comparing actual outcomes and the effectiveness of mitigation. It provides a vital step in the EIA learning process.

It is important to note here that, although the steps are outlined in linear fashion but EIA should be cyclic activity, with feedback and interaction between various steps/ stages. Further, the steps can and does vary considerably from country to country depending on the EIA legislation in a country. Therefore, the order of steps in the EIA process may also vary.

5.5.3 ENVIRONMENTAL IMPACT STATEMENT : THE DOCUMENTATION

The environmental impact statement (EIS) is the documentation of the information and estimates of impacts derived from the various steps/ stages in the EIA process. An example of the content of an EIS for a project are provided in Table 5.1 and are discussed as under :

Non-technical Summary : It is an important element in the documentation. Since EIA can be complex, therefore the non-technical summary can help in communication with the various parties involved in the process.

Methods Statement : Reflecting the potential complexity of the process, a methods statement, at the beginning, is provided in the first part of EIS. It provides an opportunity to clarify some basic information. It may include information, such as who is the project developer, who has produced the EIS, who has been consulted and how, what methods have been used, what difficulties have been encountered and what are the limitations of the EIA?

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Summery Statement of Key Issues : It is provided up-front so as to help in improving communication as well.

Monitoring Programme : The details of monitoring programme is either included along with summery statement of key issues in Part 1 : Methods and key issues or at the end of the document.

Background to the Proposed Development : It forms the second part of the EIS. It covers the early steps/ stages of EIA process, including clear descriptions of the projects and baseline conditions including the relevant planning policies and plans.

Topic Areas of EIA : The Part 3 comprises of the EIS on various topic areas. Within each of the topic areas of the EIS, there would normally be discussion of existing conditions, predicted impacts, scope for migration and residual impacts.

EIA and EIS practice vary from study to study, from country to country, and best practices are constantly evolving. Currently, several countries are in the favour of greater emphasis to the socio-economic dimension, public participation and after-the-decision activity (like monitoring).

Table 5.1 : Example of contents of an EIS for a project.

Content Page No.Non Technical Summery

Part I. Methods and issues

1. Methods statement 2. Summary of key issues3. Monitoring programme statement

Part II. Background to the proposed development

4. Preliminary studies : need, planning, alternatives, site selection.

5. Site description/ baseline conditions6. Description of proposed development7. Construction activities and programme

Part III. Environmental impact assessment – topic area

8. Land use, landscapes and visual quality9. Geology, topography and soils

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10. Hydrology and water quality11. Air quality and climate12. Ecology : terrestrial and aquatic13. Noise14. Transportation15. Socio-economic16. Inter-relationship between effects

5.5.4 PURPOSE OF EIA

EIA is an intrinsic link between economic growth and environment. If a detailed EIA precedes all developmental activities/ projects, then it will greatly help in averting subsequent adverse impacts on environment. EIA is a process with several important purposes, such as – an aid to decision-making, an aid to the formulation of development actions, an instrument for sustainable development and many more. These purposes of EIA are briefly elaborated as under.

1. An Aid to Decision-Making : for the decision-maker (e.g. local, state or national authority), EIA provides a systematic examination of the environmental implications of a proposed activity (policy, plan, program, or project) and sometimes alternatives, before than other techniques, like cost-benefit analysis. It is not a substitute associated with a proposed development action, which should lead to more rational and structured decision-making. Above all, the most important aspect of EIA process is that it has the potential to be a basis for negotiation between the project developer, public interest groups and the planning regulator. This, if taken up, can lead to an outcome that balances the interests of the development action and the environment, which is the spirit of EIA.

2. An Aid to the Formulation of Development Actions : No doubt, many developers see EIA as a costly and time-consuming hurdle in their activities. But it is not so, EIA can be of great benefit to them because it can provide them a framework for considering location and design issues and environmental issues in parallel. It can be an aid to the formulation of development actions, indicating the areas where the project can be modified to minimize or eliminate altogether the adverse impacts on the environment. The consideration of the environmental impacts early in the planning phase of development is beneficial on many counts. It can lead :

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To environmentally sensitive development;

To harmonious relations between the developer, the planning authority and the local community;

To a smoother planning permission process; and

Sometimes, as argued by the developers, to a worthwhile financial return on the extra expenditure incurred.

O’Riordan (1990) links such concepts of negotiation and redesign to the current dominant environmental themes of “Green Consumerism” and “Green Capitalism”. The emergence of a growing demand by consumers for “Green Goods” that do no harm to environment, plus a growing market of “Green technologies”, is generating a developer response. In such a scenario, EIA can be the early indicator to the developer of potential conflicts. Taking a leaf out of it, the wise developers may use the EIA process to negotiate “Green Gains” solutions that may eliminate or offset adverse environmental impacts, reduce local community’s opposition and avoid costly public inquiries.

3. An Instrument for Sustainable Development : The central role of EIA is that of a key instrument that can be used to achieve the goal of sustainable development : “development that ensures that the use of resources and the environment today does not restrict their use by future generations”. It refers to economic development that meets the needs of all without leaving future generations with fewer natural resources than those we enjoy today. The essence of this form of development is a stable relationship between human activities and the natural world, which does not diminish the prospects for future generations to enjoy a quality of life at least as good as our own.

It is widely accepted that achieving sustainable development requires balance between the economic development, social development and environmental protection. Therefore, the existing environmentally harmful developments have to be managed as best as they can be. In extreme cases, they may be closed down, but they can still leave behind residual environmental problems for decades to come. Is it not better to mitigate the harmful effects in advance, at the planning stage, or in some cases to avoid the particular development altogether? There is an old and trusted saying – Prevention is better than

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cure. This is what EIA aims at. Therefore, EIA could form a major instrument to achieve sustainable development, provided the conceptual framework is extended to the cumulative assessment of developmental policies, plans and projects on a regional basis.

Check your progress 1 Notes :

a) Write your answer in the space given below.b) Compare your answer with key, given at the end of the unit.

Que.

1. What is environmental impact assessment? Discuss its importance in relation with development plans of the country.

2. What are the main impacts of invasion on environment? How the environmental status may be evaluated?

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4. Changing perspective on EIA roles : Environmental impact analysis is sometimes seems to be controversial. The arguments for EIA vary in time, space and according to the perspective of those involved. From a minimalist defensive perspective, developers (and possibly some government officials) might see EIA as obligatory evil, an administrative futile exercise, sometimes to be gone through that might result in some minor, often cosmetic, alterations to a development that would probably have happened anyway. Even for the “Deep Ecologists” or “Deep Greens”, EIA cannot provide the 100 % certainty about the environmental consequences of development proposals; but they feel that any projects carried out under uncertainty or risky-circumstances should be abandoned. EIA and its method must straddle such perspectives.

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Today, EIA is often seen as a positive process that seeks a harmonious relationship between development and the environment. But that was not the case a few decades back. Earlier, in 1970s, EIA was seen as a defensive tool; however, in 1990s it evolved as a potentially exciting environmental and social betterment technique. Now, if one sees EIA not so much as a technique, rather as a process that is constantly changing in the face of changing environmental politics and managerial capabilities, one can visualize EIA as a sensitive barometer of environmental values in a complex environmental society. The nature and use of EIA is bound for further change as the relative values and perspectives also change.

5.6 ECOSYSTEM RESTORATION

Humans depend greatly on an ecosystem services. An eco /or ecological systems or services may be defined as a community of plants and animals interacting with each other and their abiotic, or natural, environment. Typically, ecosystems are differentiated on the basis of dominant vegetation, topography, climate, or some other criteria. Boreal forests, for example, are characterized by the predominance of coniferous trees; prairies are characterized by the predominance of grasses; the Arctic tundra is determined partly by the harsh climatic zone. In most areas of the world, the human community is an important and often dominant component of the ecosystem.

Ecosystems include not only natural areas (e.g., forests, lakes, marine coastal systems) but also human-constructed systems (e.g., urban ecosystems, agro-ecosystems, impoundments). Human populations are increasingly concentrated in urban ecosystems, and it is estimated that, by the year 2010, 50 percent of the world's population will be living in urban areas.

These ecosystem services vary greatly and include such things as erosion control, water and air purification, food, recreation, a list that could go on endlessly. To put things into a sharper perspective, at this point in time, we need ecosystems for our continued survival. There are many reasons to restore ecosystems, some include :

1. Restoring natural capital (i.e. goods and services);

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2. Mitigating climate change (e.g. through carbon sequestration);

3. Helping threatened or endangered species recover, and

4. Aesthetic reason.

There are also moral reasons to restore ecosystems. Some would say that we have degraded, and in some cases destroyed, many ecosystems so it falls on us to ‘fix’ them.

There is also the dissenting opinion that ecosystem restoration is not a valuable use of our time. Reasons for this opinion can include :

1. Restorations are not economically feasible; 2. They don’t always work; 3. They are expensive (money could be put to better uses); and that 4. Ecosystems naturally change over time and can recover by themselves.

The problem is that we cannot restore an ecosystem to the exact same state it was in before we disturbed it. This is because, as Anthony Bradshaw claims, “ecosystems are not static, but in a state of dynamic equilibrium…. [with restoration] we aim [for a] moving target.”

Even though an ecosystem may not be in its original state, the functions of the ecosystem (especially ones that provide services to us) may be more valuable than its configuration. One reason to consider ecosystem restoration is to mitigate climate change through activities such as afforestation. Afforestation involves replanting forests, which remove carbon dioxide from the air. Carbon dioxide is a leading cause of global warming and capturing it would help alleviate climate change.

5.6.1 ECOSYSTEM HEALTH

It is important to recognize the inherent difficulties in defining "health," whether at the level of the individual, population, or ecosystem. The concept of health is somewhat of an enigma, being easier to define in its absence (sickness) than in its presence. Perhaps partially for that reason, ecologists have resisted applying the notion of "health" to ecosystems. Yet, ecosystems can become dysfunctional, particularly under chronic stress from human activity. For example, the discharge of nutrients from sewage, industrial

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waste, or agricultural runoff into lakes or rivers affects the normal functioning of the ecosystem, and can result in severe impairment. Unfortunately, degraded ecosystems are becoming more the rule than the exception.

The study of the features of degraded systems, and comparisons with systems that have not been altered by human activity, makes it possible to identify the characteristics of healthy ecosystems. Healthy ecosystems may be characterized not only by the absence of signs of pathology, but also by signs of health, including measures of vigor (productivity), organization, and resilience.

Vigor can be assessed in terms of the metabolism (activity and productivity) of the system. Ecosystems differ greatly in their normal ranges of productivity. Estuaries are far more productive than open oceans, and marshes have higher productivity than deserts. Health is not evaluated by applying one standard to all systems. Organization can be assessed by the structure of the biotic community that forms an ecosystem and by the nature of the interactions between the species (both plants and animals). Invariably, healthy ecosystems have more diversity of biota than ecologically compromised systems. Resilience is the capacity of an ecosystem to maintain its structure and functions in the face of natural disturbances. Systems with a history of chronic stress are less likely to recover from normal perturbations such as drought than those systems that have been relatively less stressed.]Healthy ecosystems can also be characterized in economic, social, and human health terms. Healthy ecosystems support a certain level of economic activity. This is not to say that the ecosystem is necessarily self-sufficient, but rather that it supports economic productivity to enable the human community to meet reasonable needs. Inevitably, ecosystem degradation impinges on the long-term sustainability of the human economy that is associated with it, although in the short-term this may not be evident, as natural capital (e.g., soils, renewable resources) may be overexploited and temporarily enhance economic returns. Similarly, with respect to social well-being, healthy ecosystems provide a basis for and encourage community integration. Historically, for example, native Hawaiian groups managed their ecosystem through a well-developed social cohesiveness that provided a high degree of cooperation in fishing and farming activity.

Another reflection of ecosystem health lies directly in the public health domain. In spring 2000, a deadly strain of the bacterium E-coli (0157:H7)

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entered the public water supply in Walkerton, Ontario, Canada, causing seven deaths and making thousands sick. This small town, with a population of five thousand, is in a farming community. Inadequate manure management from cattle operations was the likely source of this tragedy.

5.6.2 HOW HEALTHY ECOSYSTEMS BECOME PATHOLOGICAL

Stress from human activity is a major factor in transforming healthy ecosystems to sick ecosystems. Chronic stress from human activity differs from natural disturbances. Natural disturbances (fires, floods, periodic insect infestations) are part of the dynamics of most ecosystems. These processes help to "reset" ecosystems by recycling nutrients and clearing space for recolonization by biota that may be better adapted to changing environments. Thus, natural perturbations help keep ecosystems healthy. In contrast, chronic and acute stress on ecosystems resulting from human activity (e.g., construction of large dams, release of nutrients and toxic substances into the air, water, and land) generally results in long-term ecological dysfunction.

Five major sources of human-induced (anthropogenic) stresses have been identified by D. J. Rapport and A. M. Friend (1979):

1. Physical restructuring,

2. Over harvesting,

3. Waste residuals,

4. Introduction of exotic species, and

5. Global change.

1. Physical Restructuring : Activities such as wetland drainage, removal of shoals in lakes, damming of rivers, and road construction fragment the landscape and alter and damage critical habitat. These activities also disrupt nutrient cycling, and cause the loss of biodiversity.

2. Over harvesting : Overexploitation is commonplace when it comes to harvesting of wildlife, fisheries, and forests. Over long periods of time, stocks of preferred species are reduced. For example, the giant redwoods that once thrived along the California coast now exist only in remnant

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patches because of overharvesting. When dominant species like the giant redwoods (arguably the world's tallest tree—one specimen was recorded at 110 meters tall with a circumference of 13.4 meters) are lost, the entire ecosystem becomes transformed. Overharvesting often results in reduced biodiversity of endemic species, while facilitating the invasion of opportunistic species.

3. Waste Residuals : Discharges from municipal, industrial, and agricultural sources into the air, water, and land have severely compromised many of the earth's ecosystems. The effects are particularly apparent in aquatic ecosystems. In some lakes that lack a natural buffering capacity, acid precipitation has eliminated most of the fish and other organisms. While the visual effect appears beneficial (water clarity goes up) the impact on ecosystem health is devastating. Systems that once contained a variety of organisms and were highly productive (biologically) become devoid of most lifeforms except for a few acid-tolerant bacteria and sediment-dwelling organisms.

4. Introduction of Exotic Species : The spread of exotics has become a problem in almost every ecosystem of the world. Transporting species from their native habitat to entirely new ecosystems can wreck havoc, as the new environments are often without natural checks and balances for the new species. In the Great Lakes Basin, the accidental introduction of two small pelagic fishes, the alewife and the rainbow smelt, combined with the simultaneous over harvesting of natural predators, such as the lake trout, led to a significant decline in native fish species. The introduction of the sea lamprey, an eel-like predacious fish that attacks larger fish, into Lake Erie and the upper Great Lakes further destabilized the native fish community. The sea lamprey contributed to the demise of the deepwater benthic fish community by preying on lake trout, whitefish, and burbot. This contributed to a shift in the fish community from one that had been dominated by large benthic to one dominated by small pelagic (fish found in the upper layers of the lake profile). This shift from bottom-dwelling fish (benthic) to surface-dwelling fish (pelagic) has now been partially reversed by yet another accidental introduction of an exotic: the zebra mussel. As the zebra mussel is a highly efficient filter of both phytoplankton and zooplankton, its presence has reduced the available food in the surface waters for pelagic fish.

However, while the benthic fish community has gained back its dominance, the preferred benthic fish species have not yet recovered

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owing to the degree of initial degradation. Overall, the increasing dominance by exotics not only altered the ecology, but also reduced significantly the commercial value of the fisheries.

5. Global Change : Rapid climate change (or climate warming) is an emerging potential global stress on all of the earth's ecosystems. In evolutionary time, there have of course been large fluctuations in climate. However, for the most part these fluctuations have occurred gradually over long periods of time. Rapid climate change is an entirely different matter. By altering both averages and extremes in precipitation, temperature, and storm events, and by destabilizing the El Niño Southern Oscillation (ENSO), which controls weather patterns over much of the southern Pacific region, many ecosystem processes can become significantly altered. Excessive periods of drought or unusually heavy rains and flooding will exceed the tolerance for many species, thus changing the biotic composition. Flooding and unusually high winds contribute to soil erosion, and at the same time add to nutrient load in rivers and coastal waters.

These anthropogenic stresses have compromised ecosystem function in most regions of the world, resulting in ecosystem distress syndrome (EDS). EDS is characterized by a group of signs, including abnormalities in nutrient cycling, productivity, species diversity and richness, biotic structure, disease prevalence, soil fertility, and so on. The consequences of these changes for human health are not inconsiderable. Impoverished biotic communities are natural harbors for pathogens that affect humans and other species.

5.6.3 ECOSYSTEM HEALTH AND HUMAN HEALTH

An important aspect of ecosystem degradation is the associated increased risk to human health. Traditionally, the concern has been with contaminants, particularly industrial chemicals that can have adverse impacts on human development, neurological functions, reproductive functions, and that appear to be causative agents in a variety of carcinomas. In addition to these serious environmental concerns (where the remedies are often technological, including engineering solutions to reduce the release of contaminants), there are a large number of other risks to human health stemming from ecological imbalance.

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Ecosystem distress syndrome results in the loss of valued ecosystem services, including flood control, water quality, air quality, fish and wildlife diversity, and recreation. One of the major signs of EDS is increased disease incidence, both in humans and other species. Human population health should thus be viewed within an ecological context as an expression of the integrity and health of the life-supporting capacity of the environment.

Ecological imbalances triggered by global climate change and other causes are responsible for increased human health risks.

Climate Change and Vector-Borne Diseases. The global infectious disease burden is on the order of several hundred million cases per year. Many vector-borne diseases are climate sensitive. Malaria, dengue fever, hantavirus pulmonary syndrome, and various forms of viral encephalitis are all in this category. All these diseases are the result of arthropod-borne viruses (arboviruses) which are transmitted to humans as a result of bites from blood-sucking arthropods.

Global climate change—particularly as it impacts both temperatures and precipitation—is highly correlated with the prevalence of vector-borne diseases. For example, viruses carried by mosquitoes, ticks, and other blood-sucking arthropods generally have increased transmission rates with rising temperatures. St. Louis encephalitis (SLE) serves as an example. The mosquito Culex tarsalis carries this virus. The percentage of bites that results in transmission of SLE is dependent on temperature, with greater transmission at higher temperatures.

The temperature dependence of vector-borne diseases is also well illustrated with malaria. Malaria is endemic throughout the tropics, with a high prevalence in Africa, the Indian subcontinent, Southeast Asia, and parts of South and Central America and Mexico. Approximately 2.4 billion people live in areas of risk, with some 350 million new infections occurring annually, resulting in approximately 2 million deaths, predominantly in young children. Untreated malaria can become a life-long affliction—general symptoms include fever, headache, and malaise.

The climate sensitivity of malaria arises owing to the nature of the interactions of parasites, vectors, and hosts, all of which impact the ultimate transmission rates to humans. The gestation time required for the parasite to become fully developed within the mosquito host (a process termed sporogony) is from

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eight to thirty-five days. When temperatures are in the range of 20°C to 27°C, the gestation time is reduced. Rainfall and humidity also have an influence. Both drought and heavy rains tend to reduce the population of mosquitoes that serve as vectors for malaria. In drier regions of the tropics, low rainfall and humidity restricts the survival of mosquitoes. Severe flooding can result in scouring of rivers and destruction of the breeding habitats for the mosquito vector, while intermediate rainfall enhances vector production.

Ecological Imbalances. Cholera is a serious and potentially fatal disease that is caused by the bacterium Vibrio cholerae. While not nearly so prevalent as malaria, cases are nonetheless numerous. In 1993, there were 296,206 new cases of cholera reported in South America; 9,280 cases were reported in Mexico; 62,964 cases in Africa; and 64,599 cases in Asia. Most outbreaks in Asia, Africa, and South America have originated in coastal areas. Symptoms of cholera include explosive watery diarrhea, vomiting, and abdominal pain. The most recent pandemic of cholera involved more regions than at any previous time in the twentieth century. The disease remains endemic in India, Bangladesh, and Africa. Vibrio cholerae has also been found in the United States—in the Gulf Coast region of Texas, Louisiana, and Florida; the Chesapeake Bay area; and the California coast.

The increase in prevalence of V. cholerae has been strongly linked to degraded coastal marine environments. Nutrient-enriched warmer coastal waters, resulting from a combination of climate change and the use of fertilizers, provides an ideal environment for reproduction and dissemination of V. cholerae. Recent outbreaks of cholera in Bangladesh, for example, are closely correlated with higher sea surface temperatures. V. cholerae attach to the surface of both freshwater and marine copepods (crustaceans), as well as to roots and exposed surfaces of macrophytes (aquatic plants) such as the water hyacinth, the most abundant aquatic plant in Bangladesh. Nutrient enrichment and warmer temperatures give rise to algae blooms and an abundance of macrophytes. The algae blooms provide abundant food for copepods, and the increasing copepod and macrophyte populations provide V. cholerae with habitat. Subsequent dispersal of V. cholerae into estuaries and fresh water bodies allows contact with humans who use these waters for drinking and bathing. Global distribution of marine pathogens such as V. cholerae is further facilitated by ballast water discharged from vessels. Ballast water contains a virtual cocktail of pathogens, including V. cholerae.

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Antibiotic Resistance and Agricultural Practice Antibiotic resistance is a growing threat to public health. Antibiotic resistant strains of Streptococcus pneumoniae, a common bacterial pathogen in humans and a leading cause of many infections, including chronic bronchitis, pneumonia, and meningitis, have greatly increased in prevalence since the mid-1970s. In some regions of the world, up to 70 percent of bacterial isolates taken from patients proved resistant to penicillin and other b-lactam antibiotics. The use of large quantities of antibiotics in agriculture and aquaculture appears to have been a key factor in the development of antibiotic resistance by pathogens in farm animals that subsequently may also infect humans. One of the most serious risks to human health from such practices is vancomycin-resistant enterococci. The use of avoparcin, an animal growth promoter, appears to have compromised the utility of vancomycin, the last antibiotic effective against multi-drug-resistant bacteria. In areas where avoparcin has been used, such as on farms in Denmark and Germany, vancomycin-resistant bacteria have been detected in meat sold in supermarkets. Avoparcin was subsequently banned by the European Union. Another example is the use of ofloxacin to protect chickens from infection and thereby enhance their growth. This drug is closely related to ciprofloxacin, one of the most widely used antibiotics in the year 2000. There have been cases of resistance to ciprofloxacin directly related to its veterinary use. In the United Kingdom, ciprofloxacin resistance developed in strains of campylobacter, a common cause of diarrhea. Multi-drug-resistant strains of salmonella have been traced to European egg production.

Food and Water Security. Agricultural practices are also responsible for a growing number of threats to public health. Some of these are related to inadequate waste management, which has resulted in parasites and bacteria entering water supplies. Others are of entirely different origins and involve apparent transfer across species of pathogens that affect both animals and humans. The most recent and spectacular example is mad cow disease, known as variant Creutzfeldt-Jakob disease in humans, a neuro-degenerative condition that, in humans, is ultimately fatal. The first case of Bovine Spongiform Encephalopathy (BSE), the animal form of the disease, was identified in Southern England in November 1981. By the fall of 2000, an outbreak had also occurred in France, and isolated cases appeared in Germany, Switzerland, and Spain. More than one hundred deaths in Europe were attributed to what has come to be commonly called mad cow disease.

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Improper manure management was the likely source of the outbreak of E. coli 0157:H7 in Walkerton, Ontario, Canada. Other health risks associated with malfunctioning agroecosystems include periodic outbreaks of cryptosporidiosis, a parasitic disease that is spread by surface runoff contaminated by feces of infected cattle. This parasite causes fever and diarrhea in immunocompetent individuals and severe diarrhea and even death in immunocompromised individuals.

5.6.4 ECOSYSTEM RESTORATION

Ecosystem pathology in some cases can be reversed simply by removing the source of stress. In cases, for example, where ecosystem degradation is the result of point-source additions of nutrients or toxic chemicals, removal of these stresses may result in considerable recovery of ecosystem health. A classic case is Lake Washington (near Seattle, Washington). This lake had become highly anoxic (oxygen-depleted) owing to a sewage outfall entering the lake. Redirecting the sewage outfall away from the lake reversed many of the signs of pathology.

In cases where it is not feasible to remove the source of stress, more innovative engineering solutions have been tried. For example, in the Kyrönjoki and Lestijoki Rivers in western Finland, spring and fall runoff leads to sharp pulses of acidity. Spring runoff from snowmelt, which releases acid from tilled or dug soils, has been particularly damaging to fish, during the critical time of year for spawning. Fish reproduction is severely curtailed, if not all together eliminated in highly acidic water. Further there have been massive fish kills resulting from the highly acidic waters. One possible remedy is to replace the original drains which take runoff from the land to the rivers with new limed drains that can neutralize the acidity. This solution has been implemented on an experimental basis and appears to substantially reduce acidic runoff.

More radical treatments for damaged ecosystems involve "ecosystem surgery." In some cases, invading exotic vegetation (such as mangroves in Hawaii) have been removed from regions, and native vegetation has been replanted. In areas of North America where wetlands have been severely depleted owing to farming, urbanization, and industrial activity, efforts have been made to establish new wetlands.

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More often than not, however, reversing ecosystem pathology is not possible. Efforts to restore the indigenous grasslands in the Jornada Experimental Range in the southwestern United States provide an example. Overgrazing by cattle has severely degraded the landscape and has lead to replacement of the native grasses by largely inedible shrubs, dominated by mesquite. Erosion by wind and episodic heavy rains have left areas between shrubs largely bare, and subsequently underlying sands have developed in dune-like fashion over a large part of the area. The resulting mesquite dunes have proven highly resistant to efforts to restore the native grasslands, although almost every intervention has been tried, including highly toxic defoliants (Agent Orange), fire, and bulldozing.

Even where it has been possible to restore some of the ecological functions of degraded ecosystems, and thus improve ecosystem health, the restoration seldom results in reestablishment of the pristine biotic community. The best that can be achieved in most cases is reestablishment of the key ecological functions that provide the required ecosystem services, such as the regulation of water, primary and secondary productivity, nutrient cycling, and pollination. In all such efforts, key indicators of ecosystem health (vigor, productivity, and resilience) are essential to monitor progress. Standard ecological indicators can be used for this purpose (e.g., measures of productivity, species composition, nutrient flows, soil fertility) along with socioeconomic and human health indicators.

Experience in efforts to restore highly damaged ecosystems suggests that ecosystem-health prevention is far more effective than restoration. For marine ecosystems, setting aside protective zones that afford a sanctuary for fish and wildlife has considerable promise. Many countries are adopting policies to establish such areas with the prospect that these healthy regions can serve as a reservoir for biota that have become depleted in the unprotected areas. Yet this remedy is not without its limits. Restoring ecosystem health is not simply a matter of replenishing lost or damaged biota. It is also a matter of reestablishing the complex interactions among ecosystem lifeforms. Having a ready source of healthy biota that could potentially recolonize damaged ecosystems is important, but it is only part of the solution.

5.6.5 PROBLEMS WITH RESTORATION

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Many people take the view that ecosystem restoration is impractical. One reason for this view is that restoration of ecosystems does not always work. There are many reasons for restoration failure. Hilderbrand et al. (2005) point out that many times uncertainty (about ecosystem functions, species relationships, and such) is not addressed, and that the time-scales set out for ‘complete’ restoration are unreasonably short. Other times an ecosystem may be so degraded that abandonment (allowing an injured ecosystem to recover on its own) may be the wisest option. Other negative impacts of ecosystem restoration can include the introduction of large predators, which may inspire doubts in people’s safety, and plants, some requiring disturbance regimes such as regular fires. High economic costs can also be a perceived as a negative impact of the restoration process. Public opinion is very important in the feasibility of a restoration; if the public believes that the costs of restoration outweigh the benefits, then support for that project is unlikely to be big, especially in small towns. In these cases people might be ready to follow the abandonment route and let the ecosystem recover on its own, which can sometimes occur relatively quickly.

Many failures have occurred in past restoration projects, many times because clear goals were not set out as the aim of the restoration. This may be because, as Peter Alpert says, “people may not [always] know how to manage natural systems effectively”. Also many assumptions are made about myths of restoration such as the carbon copy, where a restoration plan, which worked in one area, is applied to another with the same results expected, but not realized.

5.6.6 PREVENTION OF ECOSYSTEM DISRUPTIONS

Given the difficulties in reversing ecosystem degradation, and the many associated risks that arise with the loss of ecosystem health, the most effective approach is simply the prevention of ecosystem disruption. However, like many common-sense approaches, this is easier said than done. In both developed and developing countries there is a strong inclination to continue economic growth, even at the cost of severe environmental damage. Apart from selfish motivations, the argument is made that economic growth has many obvious health benefits, such as providing more efficient means of distributing food supplies, providing more plentiful food, and providing better health services and funding for research to improve standards of living. These

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are indeed benefits of economic development, and have led to substantial increases in health status worldwide.

However, at the dawn of the twenty-first century, the past is not necessarily the best guide to the future. The human population is at an alltime high, and associated pressures of human activity have led to increasing degradation of the earth's ecosystems. As ultimately healthy ecosystems are essential for life of all biota, including humans, current global and regional trends are ominous. Under these circumstances, a tradeoff between immediate material gains and long-term sustainability of humans on the planet may be the only option. If so, the solution to sustaining human health and ecosystem health becomes one of devising a new politic that places sustaining life-support systems as a precondition for betterment of the human condition.

5.7 Ecological Management

5.7.1 ECOLOGICAL MANAGEMENT

The enormous scale of the extinction crisis we are now facing poses daunting challenges. The number of species threatened with extinction is so vast that it is virtually impossible to imagine that more than a few of the most important individual species will receive detailed study. It would seem that our most realistic hope for preventing extinction on a massive scale is to manage entire systems to conserve their biodiversity. The idea is that we should manage an ecosystem and its processes in a way that will protect its structure. Our hope is that by doing so we will also protect the populations of most or all species that are part of that ecosystem.

In the last ten or fifteen years “ecological management” or “large-scale conservation” has become the mantra of many conservation organizations, both public and private. In broad outline the objectives of ecological management seem clear and unobjectionable:

To maintain hierarchical patterns of biological diversity as well as the processes and functions supporting the phenomena that spawned them. Grumbine (1994) suggests that ecological management is based on three observations:

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1. To protect biological diversity the processes that produced it must be protected as well.

2. Species richness alone is not a good measure of management success.

3. Management must be planned for the long-term, possibly even for the indefinite future, i.e., ecological management is intended to result in both a sustainable system and a set of sustainable management activities.

Groom et al. (2005) suggest a slightly different definition, one that explicitly recognizes the role of social, economic, and institutional factors in ecological management projects:

An approach to maintaining or restoring the composition, structure, and function of natural and modified ecologicals for the goal of long-term ecological and human sustainability. It is based on a collaboratively developed vision of desired future conditions that integrates ecological, socioeconomic, and institutional perspectives, applied within a geographic framework defined primarily by natural ecological boundaries (Figure 5.2).

Before discussing concerns that have been raised about ecological management, let’s outline the steps in the process that might be followed in developing an ecological management plan. According to Harwell (1997), the development of the ecological management plan falls naturally into four distinct phases:

1. Determining the current status and threats,

2. Identifying the biologically achievable management goals,

3. Characterizing societal factors that influence the choice of management goals, and

4. Establishing management goals.

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5.7.2 CURRENT STATUS AND THREATS

Before you can manage a system you have to know what its characteristics are. In the case of an ecosystem that means knowing its current status and the threats it may be facing. That means doing at least two things:

1. Determining the boundaries of the ecosystem to be managed and the types of habitat within it that are to be managed and

2. Developing a conceptual model of human influences on the ecosystem.

The threats are manifold, and nearly all are related to human pressures.

5.7.3 BIOLOGICALLY ACHIEVABLE MANAGEMENT GOALS

Once you’ve figured out what the system is that you’re trying to protect and you’ve identified the threats to the system, you have to figure out what endpoints are biologically achievable. To identify what things are possible it is necessary to select appropriate measures for the “health” of various ecological components.

An implicit part of defining biological achievable management goals is that the goals are sustainable for the indefinite future.

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Figure 5.2 : One way of envisioning the conceptual basis of ecological management.

5.7.4 SOCIETAL FACTORS

Human and societal influences except to the extent, pose a direct threat to the species. Conservation initiatives may sometimes be needed at a very broad scale, and at that very broad scale humans are almost always part of the system. That means if the system is to be managed sustainably, attention must be given not only to the needs of non-human organisms in the system but to those of humans as well.

There are three different ways in which it is necessary to assess societal factors.

1. The human activities that lead to substantial influences on or domination of ecosystems must be identified and understood.

2. The legal, economic, institutional, political, and other societal factors that affect the frequency and scale of those activities must identified and understood.

3. The values and preferences of relevant interest groups with an influence on the ecosystem must be characterized.

The last of these items may be the most difficult for many environmentalists to accept. The list of biologically achievable management goals is likely to include a range of options from those where large portions of the ecosystem are substantially free of human influence to those where large portions of the ecosystem are human-dominated or human-influenced.

5.7.5 ESTABLISHING MANAGEMENT GOALS

With all of that in place, all that is necessary is to “establish ecological sustainability goals in terms of ecological endpoints and human values.”

If you are a biologist participating in such a process, your expertise will be particularly important in defining what endpoints are achievable. While biological expertise is needed to define the range of the possible, choosing among possible endpoints is a question of values.

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Biologists have no special competence on this choosing among competing values. We can describe the consequences of different choices, but we don’t necessarily have any special standing to choose one set of consequences over another. In a discussion about choosing among endpoints, what biologists can do is to make sure that everyone discusses only scenarios that can be achieved and that everyone understands the tradeoffs among them.

As Harwell et al. (1999) point out, decisions about design and implementation of an ecological management program lie along a continuum:

1. Societal values will have a dominant role in determining the outcome of those that are predominantly concerned with defining the management goals.

2. Scientific expertise will have a dominant role in determining the outcome of those that are predominantly concerned with measuring how the system responds.

3. Societal values and scientific expertise will have equal roles in determining the system endpoints that will be measured to determine whether management goals are being achieved.

5.7.6 ADAPTIVE MANAGEMENT

Adaptive management is simply the idea that management actions are like experiments. They are tests of hypotheses about how the system works. So if we monitor the results of those tests, we can confirm or reject our hypotheses and improve our understanding of the system while we manage it. We do not have to wait until all of the answers are in. We can gather some of them while we proceed (Figure 5.3).

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Figure 5.3 : A conceptual diagram of the process of adaptive management.

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5.7.7 A CRITIQUE OF ECOLOGICAL MANAGEMENT

Goldstein (1999) argues that the ecological management not only often fails to honor those principles, but also that it is largely an attempt to bypass the requirement for life history information on all species of concern. He goes on to argue that this attempt is doomed to failure for three reasons:

1. Measures of local species richness can diminish the contribution of threatened species to priority setting.

2. Good “indicator taxa” don’t exist, i.e., it’s not possible accurately to predict community properties from the presence or absence of certain taxa.

3. Concepts like ecological integrity, ecosystem function, ecosystem resilience, ecosystem health, and naturalness don’t provide concrete guidelines for management.

His objection boils down to this:

For management strategies and techniques to be successful at preserving anything other than perceived structures, functions, and processes of landscapes, they must be evaluated against the performance of populations and metapopulations in those managed landscapes, including but not limited to the most sensitive and threatened species . . . ecological management will be successful only if ecosystem is used in a sense that can be guaged with precision and if the criteria used actually reflect the needs of natural entitites we wish to protect rather than abstracted emergent properties, functions, and processes of groups of organisms.

5.8 SUSTAINABLE DEVELOPMENT

Considering that the concept of sustainable development is now enshrined on the masthead of Environment magazine, featured on 8,720,000 Web pages and enmeshed in the aspirations of countless programs, places, and institutions, it should be easy to complete the sentence.

The most widely accepted definition is creatively ambiguous : “Humanity has the ability to make development sustainable—to ensure that it meets the

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needs of the present without compromising the ability of future generations to meet their own needs.”

This malleability allows programs of environment or development; places from local to global; and institutions of government, civil society, business, and industry to each project their interests, hopes and aspirations onto the banner of sustainable development.

A brief history of the concept, along with the interpretive differences and the common ground in definitions, goals, indicators, values, and practice follows. Taken together, these help explain what is meant by sustainable development.

5.8.1 BACKGROUND

In the last half of the twentieth century, four key themes emerged from the col-lective concerns and aspirations of the world’s peoples: peace, freedom, development, and environment. The peace that was thought to be secured in the postwar world of 1945 was immediately threatened by the nuclear arms race. Throughout the Cold War, peace was sustained globally but fought locally, often by proxies for the superpowers. While the number of wars has diminished over the last decade, peace is still sought, primarily in Africa and the Middle East.

Freedom was sought early in the post-war world in the struggle to end imperi-alism; to halt totalitarian oppression and later to extend democratic governance, human rights, and the rights of women, indigenous peoples, and minorities. The success of many former colonies in attaining national independence was followed by a focus on economic development to provide basic necessities for the poorest two-thirds of the world and higher standards of living for the wealthy third. Finally, it is only in the past 40 years that the environment (local to global) became a key focus of national and international law and institutions.

Although reinterpreted over time, peace, freedom, development, and the environment remain prominent issues and aspirations. In the 1970s and 1980s, world commissions of notables were created to study such international concerns, producing major documents that were often followed by global conferences. Characteristic of these international commissions was

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the effort to link together the aspirations of humankind—demonstrating how the pursuit of one great value required the others. Sustainable development, with its dual emphasis on the most recent concerns—development and environment—is typical of such efforts.

The World Commission on Environment and Development was initiated by the General Assembly of the United Nations in 1982, and its report, Our Common Future, was published in 1987. It was chaired by then–Prime Minister of Norway Gro Harlem Brundtland, thus earning the name the “Brundtland Com-mission.” The commission’s membership was split between developed and developing countries. Its roots were in the 1972 Stockholm Conference on the Human Environment—where the conflicts between environment and devel-opment were first acknowledged—and in the 1980 World Conservation Strat-egy of the International Union for the Conservation of Nature, which argued for conservation as a means to assist development and specifically for the sustainable development and utilization of species, ecosystems, and resources. Drawing on these, the Brundtland Commission began its work committed to the unity of environment and development.

As Brundtland argued:

The environment does not exist as a sphere separate from human actions, ambitions, and needs and attempts to defend it in isolation from human concerns have given the very word “environment” a connotation of naivety in some political circles. The word “development” has also been narrowed by some into a very limited focus, along the lines of “what poor nations should do to become richer,” and thus again is automatically dismissed by many in the international arena as being a concern of specialists, of those involved in questions of “development assistance.” But the “environment” is where we live; and “development” is what we all do in attempting to improve our lot within that abode. The two are inseparable.

As with previous efforts, major international meetings followed the report. The United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro in 1992 (the so-called “Earth Summit”) issued a declaration of principles, a detailed Agenda 21 of desired actions, international agreements on climate change and biodiversity, and a statement of principles on forests. Ten years later, in 2002, at the World Summit on Sustainable Development in Johannesburg, South Africa, the commitment to sustainable development was reaffirmed. In the interim, sustainable development as a concept, as a goal,

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and as a movement spread rapidly and is now central to the mission of count-less international organizations, national institutions, corporate enterprises, “sustainable cities,” and locales.

5.8.2 DEFINITIONS

The Brundtland Commission’s brief definition of sustainable development is the “ability to make development sustainable—to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs” is surely the standard definition when judged by its widespread use and frequency of citation. The use of this definition has led many to see sustainable development as having a major focus on intergenerational equity. Although the brief definition does not explicitly men-tion the environment or development, the subsequent paragraphs, while rarely quoted, are clear. On development, the report states that human needs are basic and essential; that economic growth—but also equity to share resources with the poor—is required to sustain them; and that equity is encouraged by effective citizen participation. On the environment, the text is also clear:

The concept of sustainable development does imply limits—not absolute limits but limitations imposed by the present state of technology and social organization on environmental resources and by the ability of the biosphere to absorb the effects of human activities.

In the years following the Brundtland Commission’s report, the creative ambi-guity of the standard definition, while allowing a range of disparate groups to assemble under the sustainable development tent, also created a veritable industry of deciphering and advocating what sustainable development really means. One important study—by the Board on Sustainable Development of the U.S. National Academy of Sciences—sought to bring some order to the broad literature its members reviewed. In its report, Our Common Journey: a Transition toward Sustainability, the board focused on the seemingly inherent distinction between what advocates and analysts sought to sustain and what they sought to develop, the relationship between the two, and the time horizon of the future.

Thus under the heading “what is to be sustained,” the board identified three major categories—nature, life support systems, and community—as well as intermediate categories for each, such as Earth, environment, and cultures.

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Drawing from the surveyed literature, the board found that most commonly, emphasis was placed on life support systems, which defined nature or envi-ronment as a source of services for the utilitarian life support of humankind. The study of ecosystem services has strengthened this definition over time. In contrast, some of the sustainable development literature valued nature for its intrinsic value rather than its utility for human beings. There were also parallel demands to sustain cultural diversity, including livelihoods, groups, and places that constitute distinctive and threatened communities.

Similarly, there were three quite distinct ideas about what should be devel-oped: people, economy, and society. Much of the early literature focused on economic development, with productive sectors providing employment, desired consumption, and wealth. More recently, attention has shifted to human development, including an emphasis on values and goals, such as increased life expectancy, education, equity, and opportunity. Finally, the Board on Sustainable Development also identified calls to develop society that emphasized the values of security and well-being of national states, regions, and institutions as well as the social capital of relationships and community ties.

There was ready agreement in the literature that sustainable development implies linking what is to be sustained with what is to be developed, but here, too, the emphasis has often differed from extremes of “sustain only” to “develop mostly” to various forms of “and/or.” Similarly, the time period of concern, ambiguously described in the standard definition as “now and in the future,” has differed widely. It has been defined from as little as a generation—when almost everything is sustainable—to forever—when surely nothing is sustainable.

The 2002 World Summit on Sustainable Development marked a further expansion of the standard definition with the widely used three pillars of sustainable development: economic, social, and environmental. The Johan-nesburg Declaration created “a collective responsibility to advance and strengthen the interdependent and mutually reinforcing pillars of sustainable development—economic development, social development and environmental protection—at local, national, regional and global levels.” In so doing, the World Summit addressed a running concern over the limits of the framework of environment and development, wherein development was widely viewed solely as economic development. For many under the common

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tent of sustainable development, such a narrow definition obscured their concerns for human development, equity, and social justice.

Thus while the three pillars were rapidly adopted, there was no universal agreement as to their details. A Web search of the phrase “three pillars of sustainable development” finds a wide variety of environmental, economic, and social pillars with differences most pronounced in characterizing the social pillar. Three major variants of social development are found, each of which seeks to compensate for elements missing in the narrow focus on economic development. The first is simply a generic non-economic social designation that uses terms such as “social,” “social development,” and “social progress.” The second emphasizes human development as opposed to economic development: “human development,” “human well-being,” or just “people.” The third variant focuses on issues of justice and equity: “social justice,’’ “equity,” and “poverty alleviation.”

5.8.3 GOALS

Another way to define sustainable development is in what it specifically seeks to achieve. To illustrate, it is helpful to examine three sets of goals that use different time-horizons: the short-term (2015) goals of the Millennium Decla-ration of the United Nations; the two-generation goals (2050) of the Sustain-ability Transition of the Board on Sustainable Development; and the long-term (beyond 2050) goals of the Great Transition of the Global Scenario Group.

UN Millennium Declaration

To mark the millennium, heads of state gathered in New York at the United Nations in September 2000. There, the UN General Assembly adopted some 60 goals regarding peace; development; environment; human rights; the vulnerable, hungry, and poor; Africa; and the United Nations. Many of these contained specific targets, such as cutting poverty in half or insuring universal primary school education by 2015. For eight of the major goals, progress is monitored by international agencies. In 2004, these agencies concluded that at existing rates of progress, many countries will fall short of these goals, particularly in Africa. Yet the goals still seemed attainable by collective action by the world community and national governments. To do so, the Millenni-um Project, commissioned by the UN secretary-general, recently estimated that the additional financial resources that would be required to meet the

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Millennium Development Goals are $135 billion in 2006, rising to $195 billion in 2015. This roughly represents a doubling of official aid flows over current levels and is still below the UN goal of aid flows from industrialized to developing countries of 0.7 percent of the gross national product for industri -alized countries.

Sustainability Transition of the Board on Sustainable Development

In 1995, the Board on Sustainable Development of the U.S. National Academy of Sciences sought to make sustainable development more mean-ingful to scientific analysis and contributions. To do so, the board decided to focus on a two-generation time horizon and to address the needs of a global population with half as many more people as there are today—needs that, if met successfully, are not likely to be repeated within the next century or two because of the demographic transition. In that time period, the board suggested that a minimal sustainability transition would be one in which the world provides the energy, materials, and information to feed, nurture, house, educate, and employ the many more people of 2050—while reducing hunger and poverty and preserving the basic life support systems of the planet. To identify more specific goals, of meeting human needs, reducing hunger and poverty, and preserving the basic life support systems of the planet, the board searched the text and statements from recent global conferences, world summits, international environmental treaties, and assessments. In so doing, the board in 1995 anticipated the 2000 Millennium Declaration goals, many of which were incorporated into its analysis of goals and targets. Less sanguine than the UN, the board determined it would take a generation to reach the 2015 goals of the Millennium Declaration and another generation to achieve the board’s goals of meeting human needs for a 2050 population.

Great Transition of the Global Scenario Group

With the assistance of the Global Scenario Group, the Board on Sustainable Development conducted a scenario analysis of a proposed “Sustainability Transition,” focusing specifically on hunger and the emission of greenhouse gasses. This initial analysis served as the subsequent basis of the Policy Reform Scenario of the Global Scenario Group and concluded that a sustainability transition is possible without positing either a social revolution or a technological miracle. But it is “just” possible, and the technological and social requirements to move from business as usual—without changing

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lifestyles, values, or economic system—is daunting. Most daunting of all is the governmental commitment required to achieve it and the political will to do so.

Finally, the Global Scenario Group also prepared a more idealistic Great Transition Scenario that not only achieved the goals of the sustainability transition outlined by the Board on Sustainable Development but went further to achieve for all humankind “a rich quality of life, strong human ties and a resonant connection to nature.” In such a world, it would be the quality of human knowledge, creativity, and self-realization that represents development, not the quantity of goods and services. A key to such a future is the rejection of material consumption beyond what is needed for fulfillment or for a “good life.” Beyond these goals, however, the details of this good life are poorly described.

5.8.4 INDICATORS

Still another way to define sustainable development is in how it is measured. Indeed, despite sustainable development’s creative ambiguity, the most seri-ous efforts to define it, albeit implicit in many cases, come in the form of indicators. Combining global, national, and local initiatives, there are literally hundreds of efforts to define appropriate indicators and to measure them. Recently, a dozen such efforts were reviewed. Half were global in coverage, using country or regional data (the UN Commission on Sustainable Devel-opment, Consultative Group on Sustainable Development Indicators, Wellbe-ing Index, Environmental Sustainability Index, Global Scenario Group, and the Ecological Footprint). Of the remaining efforts, three were country studies (in the United States, the Genuine Progress Indicator and the Interagency Working Group on Sustainable Development Indicators, and in Costa Rica, the System of Indicators for Sustainable Development); one was a city study (the Boston Indicators Project); one was global in scope but focused on indicators of unsustainability (State Failure Task Force); and one focused on corporate and nongovernmental entities (Global Reporting Initiative).

Table 5.2 lists each study with its source, the number of indicators used, and the implicit or explicit definitions used to describe what is to be sustained, what is to be developed, and for how long.

Two major observations emerge. The first is the extraordinarily broad list of items to be sustained and to be developed. These reflect the inherent mal-

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leability of “sustainable development” as well as the internal politics of the measurement efforts. In many of the cases, the initiative is undertaken by a diverse set of stakeholders, and the resulting lists reflect their varied aspi-rations. For example, in the UN Commission on Sustainable Development, the stakeholders are nations negotiating how to measure their relative progress or lack of progress toward sustainable development. In the Boston Indicators Project, the stakeholders are community members with varied opinions about desirable goals, policies, and investment priorities for the future. In the Global Reporting Initiative, the stakeholders are corporations, investors, regulatory agencies, and civil society groups discussing how to account for corporate actions affecting sustainable development. With many stakeholders, each with different definitions, achieving consensus often takes the form of long “laundry lists” of indicators, and definitional differences are downplayed in favor of reaching a common set of indicators. Thus, to be inclusive, the range of indicators becomes very broad. Half the examined initiatives, however, represent less-inclusive research or advocacy groups who share a more narrow and homogenous view of sustainable development. While also assembling large numbers of indicators, these groups tend to aggregate them to reflect their distinctive vision of sustainability.

A second observation is that few of the efforts are explicit about the time period in which sustainable development should be considered. Despite the emphasis in the standard definition on intergenerational equity, there seems in most indicator efforts a focus on the present or the very short term. Three exceptions, however, are worth noting: The UN Commission on Sustainable Development uses some human development indicators defined in terms of a single generation (15–25 years), the Global Scenario Group quantifies its scenarios through 2050 (approximately two generations), and the Ecological Footprint argues that in the long run an environmental footprint larger than one Earth cannot be sustained. Overall, these diverse indicator efforts reflect the ambiguous time horizon of the standard definition—“now and in the future.”

Table 5.2 : Definitions of sustainable development implicitly or explicitly adopted by selected indicator initiatives

Indicator initiative

Number of

indicator

Implicit or explicit

definition

What is to be sustained?

What is to be developed?

For how long?

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s ?

Commission on Sustainable Developmenta

58 Implicit, but informed by Agenda 21

Climate, clean air, land productivity, ocean productivity, fresh water, and biodiversity

Equity, health, education, housing, security, stabilized population

Sporadic references to 2015

Consultative Group on Sustainable Development Indicatorsb

46 Same as above

Same as above Same as above Not stated; uses data for 1990 and 2000

Wellbeing

Indexc

88 Explicit “A condition in which the ecosystem maintains its diversity and quality—and thus its capacity to support people and the rest of life—and its potential to adapt to change and provide a wide change of choices and opportunities for the future”

“A condition in which all members of society are able to determine and meet their needs and have a large range of choices to meet their potential”

Not stated; uses most recent data as of 2001 and includes some indicators of recent change (such as inflation and deforestation)

Environmental

Sustainability

Indexd

68 Explicit “Vital environmental systems are maintained at healthy levels, and to the extent to which levels are improving rather than deteriorating” [and] “levels of anthropogenic stress are low enough to engender no

Resilience to environmental disturbances (“People and social systems are not vulnerable (in the way of basic needs such as health and nutrition) to environmental disturbances; becoming less vulnerable is a

Not stated; uses most recent data as of 2002 and includes some indicators of recent change (such as deforestation) or predicted

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demonstrable harm to its environmental systems.”

sign that a society is on a track to greater sustainability”); “institutions and underlying social patterns of skills, attitudes, and networks that foster effective responses to environmental challenges”; and cooperation among countries “to manage common environmental problems”

change (such as population in 2025)

Genuine Progress

Indicatore

26 Explicit Clean air, land, and water

Economic performance, families, and security

Not stated; computed annually from 1950–2000

Global Scenario

Groupf

65 Explicit “Preserving the essential health, services, and beauties of the earth requires stabilizing the climate at safe levels, sustaining energy, materials, and water resources, reducing toxic emissions, and maintaining the world’s ecosystems and habitats.”

Institutions to “meet human needs for food, water, and health, and provide opportunities for education, employment and participation”

Through 2050

Ecological 6 Explicit “The area of biologically

Not explicitly stated; computed annually from 1961–1999

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Footprintg productive land and water required to produce the resources consumed and to assimilate the wastes produced by humanity”

U.S. Interagency Working Group on Sustainable Development Indicatorsh

40 Explicit Environment, natural resources, and ecosystem services

Dignity, peace, equity, economy, employment, safety, health, and quality of life

Current and future generations

Costa Ricai 255 Implicit Ecosystem services, natural resources, and biodiversity

Economic and social development

Not stated; includes some time series dating back to 1950

Boston Indicator

Projectj

159 Implicit Open/green space, clean air, clean water, clean land, valued ecosystems, biodiversity, and aesthetics

Civil society, culture, economy, education, housing, health, safety, technology, and transportation

Not stated; uses most recent data as of 2000 and some indicators of recent change (such as change in poverty rates)

State Failure

Task Forcek

75 Explicit Intrastate peace/security

Two years

Global Reporting

Initiativel

97 Implicit Reduced consumption of raw materials and

Profitability, employment, diversity of

Current reporting year

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reduced emissions of environmental contaminants from production or product use

workforce, dignity of workforce, health/safety of workforce, and health/safety/privacy of customers

5.8.5 VALUES

Still another mode of defining sustainable development is through the values that represent or support sustainable development. But values, like sustain-able development, have many meanings. In general, values are expressions of, or beliefs in, the worth of objects, qualities, or behaviors. They are typically expressed in terms of goodness or desirability or, conversely, in terms of badness or avoidance. They often invoke feelings, define or direct us to goals, frame our attitudes, and provide standards against which the behaviors of individuals and societies can be judged. As such, they often overlap with sustainability goals and indicators. Indeed, the three pillars of sustainable development; the benchmark goals of the Millennium Declaration, the Sustainability Transition, and the Great Transition; and the many indicator initiatives are all expressions of values.

But these values, as described in the previous sections, do not encompass the full range of values supporting sustainable development. One explicit statement of supporting values is found in the Millennium Declaration. Underlying the 60 specific goals of the Millennium Declaration is an articulated set of fundamental values seen as essential to international relations: freedom, equality, solidarity, tolerance, respect for nature, and shared responsibility (see the box on page 16).

The Millennium Declaration was adopted by the UN General Assembly, but the origins of the declaration’s set of fundamental values are unclear. In contrast, the origins of the Earth Charter Initiative—which defines the Earth Charter as a “declaration of fundamental principles for building a just, sustainable, and peaceful global society in the 21st century”- is well docu-mented.

Check your progress 2. Notes :

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a) Write your answer in the space given below.b) Compare your answer with key, given at the end of the unit.

Que. 3. What is sustainable development? Discuss its indicators, goals, and values.4. What is environmental management?

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

The initiative answers the call of the World Commission on Environment and Development for creation of “a universal declaration” that would “consolidate and extend relevant legal principles,” create “new norms . . . needed to maintain livelihoods and life on our shared planet,” and “ guide state behavior in the transition to sustainable development.” An effort to draft a charter at the 1992 Earth Summit was unsuccessful. In 1994 a new Earth Charter Initiative was launched that involved “the most open and participatory consultation process ever conducted in connection with an international document. Thousands of individuals and hundreds of organizations from all regions of the world, different cultures, and diverse sectors of society . . . participated.” Released in the year 2000, the Earth Charter has been endorsed by more than 14,000 individuals and organizations worldwide representing millions of members, yet it has failed to attain its desired endorsement or adoption by the 2002 World Summit on Sustainable Development or the UN General Assembly.

The values of the Earth Charter are derived from “contemporary science, international law, the teachings of indigenous peoples, the wisdom of the world’s great religions and philosophical traditions, the declarations and reports of the seven UN summit conferences held during the 1990s, the global ethics movement, numerous nongovernmental declarations and people’s treaties issued over the past thirty years, and best practices for building sustainable communities.” For example, in 1996, more than 50 international law instruments were surveyed and summarized in Principles of

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Environmental Conservation and Sustainable Development: Summary and Survey. Four first-order principles were identified and expressed in the Earth Charter as the community of life, ecological integrity, social and economic justice, and democracy, nonviolence, and peace. Sixteen second-order principles expand on these four, and 61 third-order principles elaborate on the 16. For example, the core principal of social and economic justice is elaborated by principles of equitable economy, eradication of poverty, and the securing of gender equality and the rights of indigenous peoples. In turn, each of these principles is further explicated with three or four specific actions or intentions.

5.8.6 PRACTICE

Finally—and in many ways, most importantly—sustainable development is defined in practice. The practice includes the many efforts at defining the concept, establishing goals, creating indicators, and asserting values. But additionally, it includes developing social movements, organizing institutions, crafting sustainability science and technology, and negotiating the grand compromise among those who are principally concerned with nature and environment, those who value economic development, and those who are dedicated to improving the human condition.

A Social Movement

Sustainable development can be viewed as a social movement—“a group of people with a common ideology who try together to achieve certain general goals.” In an effort to encourage the creation of a broadly based social move-ment in support of sustainable development, UNCED was the first interna-tional, intergovernmental conference to provide full access to a wide range of nongovernmental organizations (NGOs) and to encourage an independent Earth Summit at a nearby venue. More than 1,400 NGOs and 8,000 journalists participated. One social movement launched from UNCED was the effort described above to create an Earth Charter, to ratify it, and to act upon its principles.

In 2002, 737 new NGOs and more than 8,046 representatives of major groups (business, farmers, indigenous peoples, local authorities, NGOs, the scientific and technological communities, trade unions, and women) attended the World Summit on Sustainable Development in Johannesburg. These groups

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organized themselves into approximately 40 geographical and issue-based caucuses.

But underlying this participation in the formal international sustainable development events are a host of social movements struggling to identify what sustainable development means in the context of specific places and peoples. One such movement is the effort of many communities, states, provinces, or regions to engage in community exercises to define a desirable sustainable future and the actions needed to attain it. Examples include Sustainable Seattle, Durban’s Local Agenda 21 Programme, the Lancashire County Council Local Agenda 21 Strategy, and the Minnesota Sustainable Development Initiative.

Three related efforts are the sustainable livelihoods movement, the global solidarity movement, and the corporate responsibility movement. The move-ment for sustainable livelihoods consists of local initiatives that seek to create opportunities for work and sustenance that offer sustainable and credible alternatives to current processes of development and modernization. Consisting primarily of initiatives in developing countries, the movement has counterparts in the developed world, as seen, for example, in local efforts in the United States to mandate payment of a “living wage” rather than a minimum wage.

The global solidarity movement seeks to support poor people in developing countries in ways that go beyond the altruistic support for development fund-ing. Their campaigns are expressed as antiglobalization or “globalization from below” in critical appraisals of major international institutions, in the movement for the cancellation of debt, and in critiques of developed-world policies—such as agricultural subsidies—that significantly impact developing countries and especially poor people.

The corporate responsibility movement has three dimensions: various cam-paigns by NGOs to change corporate environmental and social behavior; efforts by corporations to contribute to sustainable development goals and to reduce their negative environmental and social impacts; and international initiatives such as the UN Global Compact or the World Business Council for Sustainable Development that seek to harness the knowledge, energies, and activities of corporations to better serve nature and society. For instance, in the just-selected Global 100, the most sustainable corporations in the world, the top three corporations were Toyota, selected for its leadership in

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introducing hybrid vehicles; Alcoa, for management of materials and energy efficiency; and British Petroleum, for leadership in greenhouse gas emissions reduction, energy efficiency, renewables, and waste treatment and handling.

A related social movement focuses on excessive material consumption and its impacts on the environment and society and seeks to foster voluntary simplicity of one form or another. These advocates argue that beyond certain thresholds, ever-increasing consumption does not increase subjective levels of happiness, satisfaction, or health. Rather, it often has precisely the oppo-site effect. Thus, these efforts present a vision of “the good life” in which people work and consume less than is prevalent in today’s consumer-driven affluent societies.

As with any social movement, sustainable development encounters oppo-sition. The opponents of sustainable development attack from two very dif -ferent perspectives: At one end of the spectrum are those that view sustainable development as a top-down attempt by the United Nations to dictate how the people of the world should live their lives—and thus as a threat to individual freedoms and property rights. At the other end are those who view sustainable development as capitulation that implies development as usual, driven by the interests of big business and multilateral institutions and that pays only lip service to social justice and the protection of nature.

Institutions

The goals of sustainable development have been firmly embedded in a large number of national, international, and nongovernmental institutions. At the intergovernmental level, sustainable development is now found as a central theme throughout the United Nations and its specialized agencies. Evidence of this shift can be seen in the creation of the Division of Sustainable Development within the United Nations Department of Economic and Social Affairs, the establishment of a vice president for environmentally and socially sustainable development at the World Bank, and the declaration of the United Nations Decade of Education for Sustainable Development. Similarly, numerous national and local governmental entities have been established to create and monitor sustainable development strategies. According to a recent survey by the International Council for Local Environment Initiatives, “6,416 local authorities in 113 countries have either made a formal commitment to Local Agenda 21 or are actively undertaking the process,” and the number of

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such processes has been growing dramatically. In addition to these gov-ernmental efforts, sustainable development has emerged in the organization charts of businesses (such as Lafarge), consultancies (including CH2M Hill), and investment indices (such as the Dow Jones Sustainability Index).

Sustainability Science and Technology

Sustainable development is also becoming a scientific and technological endeavor that, according to the Initiative on Science and Technology for Sustainable Development, “seeks to enhance the contribution of knowledge to environmentally sustainable human development around the world.” This emerging enterprise is focused on deepening our understanding of socio--ecological systems in particular places while exploring innovative mechanisms for producing knowledge so that it is relevant, credible, and legitimate to local decision makers.

The efforts of the science and technology community to contribute to sustainable development is exemplified in the actions of the major Academies of Science and International Disciplinary Unions, in collaborative networks of individual scientists and technologists, in emerging programs of interdisciplinary education, and in many efforts to supply scientific support to communities.

A Grand Compromise

One of the successes of sustainable development has been its ability to serve as a grand compromise between those who are principally concerned with nature and environment, those who value economic development, and those who are dedicated to improving the human condition. At the core of this compromise is the inseparability of environment and development described by the World Commission on Environment and Development.

Thus, much of what is described as sustainable development in practice are negotiations in which workable compromises are found that address the environmental, economic, and human development objectives of competing interest groups. Indeed, this is why so many definitions of sustainable development include statements about open and democratic decisionmaking.

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At the global scale, this compromise has engaged the wealthy and poor coun-tries of the world in a common endeavor. Before this compromise was formally adopted by UNCED, the poorer countries of the world often viewed demands for greater environmental protection as a threat to their ability to develop, while the rich countries viewed some of the development in poor countries as a threat to valued environmental resources. The concept of sustainable development attempts to couple development aspirations with the need to preserve the basic life support systems of the planet.

5.8.7 SO, WHAT IS SUSTAINABLE DEVELOPMENT?

Since the Brundtland Commission first defined sustainable development, dozens, if not hundreds, of scholars and practitioners have articulated and promoted their own alternative definition; yet a clear, fixed, and immutable meaning remains elusive. This has led some observers to call sustainable development an oxymoron: fundamentally contradictory and irreconcilable. Further, if anyone can redefine and reapply the term to fit their purposes, it becomes meaningless in practice, or worse, can be used to disguise or greenwash socially or environmentally destructive activities.

Yet, despite these critiques, each definitional attempt is an important part of an ongoing dialogue. In fact, sustainable development draws much of its resonance, power, and creativity from its very ambiguity. The concrete challenges of sustainable development are at least as heterogeneous and complex as the diversity of human societies and natural ecosystems around the world. As a concept, its malleability allows it to remain an open, dynamic, and evolving idea that can be adapted to fit these very different situations and contexts across space and time. Likewise, its openness to interpretation enables participants at multiple levels, from local to global, within and across activity sectors, and in institutions of governance, business, and civil society to redefine and reinterpret its meaning to fit their own situation.

Thus, the concept of sustainability has been adapted to address very different challenges, ranging from the planning of sustainable cities to sustainable livelihoods, sustainable agriculture to sustainable fishing, and the efforts to develop common corporate standards in the UN Global Compact and in the World Business Council for Sustainable Development.

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Despite this creative ambiguity and openness to interpretation, sustainable development has evolved a core set of guiding principles and values, based on the Brundtland Commission’s standard definition to meet the needs, now and in the future, for human, economic, and social development within the restraints of the life support systems of the planet. Further, the connotations of both of the phrase’s root words, “sustainable” and “development” are generally quite positive for most people, and their combination imbues this concept with inherent and near-universal agreement that sustainability is a worthwhile value and goal—a powerful feature in diverse and conflicted social contexts.

Importantly, however, these underlying principles are not fixed and immutable but the evolving product of a global dialogue, now several decades old, about what sustainability should mean. The original emphasis on economic devel-opment and environmental protection has been broadened and deepened to include alternative notions of development (human and social) and alternative views of nature (anthropocentric versus ecocentric). Thus, the concept maintains a creative tension between a few core principles and openness to reinterpretation and adaptation to different social and ecological contexts.

Sustainable development thus requires the participation of diverse stakeholders and perspectives, with the ideal of reconciling different and sometimes opposing values and goals toward a new synthesis and subsequent coordination of mutual action to achieve multiple values simultaneously and even synergistically.

As real-world experience has shown, however, achieving agreement on sus-tainability values, goals, and actions is often difficult and painful work, as different stakeholder values are forced to the surface, compared and contrasted, criticized and debated. Sometimes individual stakeholders find the process too difficult or too threatening to their own values and either reject the process entirely to pursue their own narrow goals or critique it ideologically, without engaging in the hard work of negotiation and compromise.

Critique is nonetheless a vital part of the conscious evolution of sustainable development—a concept that, in the end, represents diverse local to global efforts to imagine and enact a positive vision of a world in which basic human needs are met without destroying or irrevocably degrading the natural sys-tems on which we all depend.

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5.9 LETS SUM UP

Every ecosystem is subject to perturbations such as climate, nutrient fluctuation, loss of biodiversity, and introduction of exotic species, that can alter ecosystem structure and function.

Whittaker (1972) distinguished three types of diversity viz alpha, beta and gamma diversity.

Robert MacArthur [2002] proposed measuring the stability of an ecosystem. In 1975, Daniel Goodman summarized the mounting evidence against the diversity stability hypothesis by responding to each of Elton’s arguments for it.

Invasive species are non-indigenous plants or animals species that adversely affect the habitats they invade economically, environmentally or ecologically. Biological species invasions alter ecosystems in a multitude of ways. Worldwide, an estimated 80% of endangered species could suffer losses by competition with, or predation by, invasive species.

Environmental Impact Assessment (EIA) is an important management tool for ensuring optimal use of natural resources for sustainable development. EIA is a relatively new planning and decision-making tool.

EIA extrapolates from scientific knowledge to assess the problem consequences of some human interventions on nature.

Grumbine (1994) suggests the ecological management which is based on three observations a. to protect biological diversity the processes that produced it must be protected as well; b. species richness alone is not a good measure of management success; and c. management must be planned for the long-term, possibly even for the indefinite future, i.e., ecological management is intended to result in both a sustainable system and a set of sustainable management activities.

Goldstein (1999) argues that the ecological management not only often fails to honor those principles, but also that it is largely an attempt to bypass the requirement for life history information on all species of concern.

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The concept of sustainable development is “Humanity has the ability to make development sustainable—to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs.”

The three pillars of sustainable development; the benchmark goals of the Millennium Declaration, the Sustainability Transition, and the Great Transition; and the many indicator initiatives are all values of the sustainable development.

Sustainable development thus requires the participation of diverse stakeholders and perspectives, with the ideal of reconciling different and sometimes opposing values and goals toward a new synthesis and subsequent coordination of mutual action to achieve multiple values simultaneously and even synergistically.

5.10 CHECK YOUR PROGRESS : THE KEY

1) Environmental Impact Assessment (EIA) is an important management tool for ensuring optimal use of natural resources for sustainable development. EIA is a relatively new planning and decision-making tool. Describe its importance in Indian context.

2) There are two main impacts of invasion :

a. Ecological impactsb. Genetic pollution

Give economic benefits in forestry, costs, agriculture, and tourism sector.

3) These are parameter of sustainability measurement. The measurements used as the quantitative basis for the informed management of sustainability. The metrics used for the measurement of sustainability include indicators, benchmarks, audits, indexes, accounting and reporting systems and more, and they can apply on all scales from global to local.

4) To protect biological diversity the processes that produced it must be protected as well. Species richness alone is not a good measure of management success.

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5) Management must be planned for the long-term, possibly even for the indefinite future, i.e., ecological management is intended to result in both a sustainable system and a set of sustainable management activities.

5.11 ASSIGNMENTS/ ACTIVITIES

It is compulsory for every student to complete an assignment/ activity/ project work from any known prospects of present study. Explain the following (any one):

a. Ecological diversity and stability

b. Invasive plant species and impact on ecosystem

c. Environmental management

d. Environmental priorities in India.

e. Environmental monitoring

f. Bioindicators

g. Sustainable development : goals, indicators, values, and practices

5.12 REFERENCES/ FURTHER READINGS

B. Walker. 1999. The ecosystem approach to conservation: Reply to Goldstein. Conservation Biology, 13:436–437.

Cadotte, M. W., McMahon, S. M. & Fukami, T. (eds) 2005 Conceptual ecology and invasions biology: reciprocal approaches to nature. Dordrecht, The Netherlands: Springer.

Lehman, Clarence and Tilman, David. 2000. “Biodiversity, Stability, and Productivity in Competitive Communities.” American Naturalist 156: 534-552.

M. A. Harwell, V. Myers, T. Young, A. Bartuska, N. Gassman, J. H. Gentile, C. C. Harwell, S. Appelbaum, J. Barko, B. Causey, C. Johnson, A. McLean, R. Smola, P. Templet, and S. Tosini. 1999. A framework for an ecosystem integrity report card. Bio Science, 49:543–556.

M. G. Marshall and T. R. Gurr, Peace and Conflict 2003. College Park, MD: Center for International Development and Conflict Management, University of Maryland.

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M. Groom, G. K. Meffe, and C. R. Carroll. 2005. Principles of Conservation Biology. Sinauer Associates, Sunderland, MA, 3rd edition.

May, Robert. 1974. Stability and Complexity in Model Ecosystems. 2nd Edition. Princeton: Princeton University Press.

National Research Council, Policy Division, Board on Sustainable Development. 1999. Our Common Journey: A Transition toward Sustainability. National Academy Press, Washington, DC.

P. G. Risser. 1999. Examining relationships between ecosystem function and biodiversity: Reply to Goldstein. Conservation Biology, 13:438–439.

P. Z. Goldstein. 1999. Functional ecosystems and biodiversity buzzwords. Conservation Biology , 13:247–255.

R. E. Grumbine. 1994. What is ecosystem management? Conservation Biology, 11:41–47.

Shrader-Frechette, Kristin and McCoy, Earl. 1993. Method in Ecology. Cambridge, UK: Cambridge University Press.

Tilman, D. 1989 Ecological experimentation: strengths and conceptual problems. In Long-term studies in ecology: approaches and alternatives (ed. G. E. Likens), pp. 136–157. New York: Springer-Verlag.

Whittaker, R. H. 1975 Communities and ecosystems, 2nd edn New York: MacMillan.

World Commission on Environment and Development (WCED), 1987. Our Common Future, Oxford University Press, New York.

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