nov 14 conservation in human-modified landscapes

8/13/2019 Nov 14 Conservation in Human-modified Landscapes

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Conservation in human-modified landscapes

LIFS 4301 Conservation BiologyNov 14th 2013


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Outline

A history of human modification and the concept ofwild nature

Conservation in a human-modified world Selectively logged forests

Agroforestry systems Tree plantations Agricultural land

Urban areas Conservation and human livelihoods in modified

landscapes


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Human impact

Efforts to improve human welfare have led tolandscapes and ecosystems worldwide beingdomesticated to enhance food supplies and reduceexposure to natural dangers

Human beings have released toxic syntheticorganic chemicals, many of which are endocrinedisrupters, that are now distributed from pole topole.


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Endocrine disruption and biological diversity

Over 80 000 new chemicals since the beginning of

the Industrial Revolution

They have dispersed widely, many globally

No organism has evolved any metabolic protectionsagainst potential harm


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They alter fertility, cognition, immune andcardiovascular function, and interactions amongspecies: several environmental estrogens decreasethe efficacy of communication between Rhizobium

bacteria and their leguminous hosts, reducingnitrogen fixation.

How large a role endocrine disruption plays inbiodiversity declines isnt yet clear, because fewconservation biologists have included thesemechanisms in the suite of hypotheses their studies

are designed to test.


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Anthropogenic biomes Some ecologists consider that the traditional

concept of an intact ecosystem is obsolete, andinstead propose a classification system based onglobal patterns of human interaction withecosystems --- anthropogenic biomes

For many types of ecosystems, large areas of intactvegetation simply no longer exist

For example, the Atlantic forest hotspot of Brazil hasbeen reduced, except for a few conservation units,to a fragmented network of very small remnants


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Anthropogenic biomes


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Anthropogenic biomes Many contemporary pristine habitats have in fact

undergone some form of human disturbance in thepast

The Upper Xingu region of Brazil comprises one ofthe largest contiguous tracts of tropical rainforest inthe Amazon today. Emerging archaeologicalevidence suggests that parts of this region hadbeen densely populated with pre-European humansettlements (1250 to 1600 A.D.), and that extensiveforests underwent large-scale transformation toagricultural areas and urbanized centers


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Anthropogenic biomes Much of the lowland rainforests of the Congo basin

had similarly experienced extensive humanhabitation, forest clearance, and agriculturalactivities between 3000 and 1600 years ago

Many further examples of extensive pre-Europeandisturbance have been found in areas thatconservationists today frequently describe as

pristine or intact, including Southeast Asia,Papua New Guinea and Central America

Forest regeneration followed the abandonment ofhuman settlements and agricultural activities


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Anthropogenic biomes


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Outline





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Integrate conservation effortswith other human activities

First, the sheer extent to which we have dominatedthe biosphere (terrestrial, freshwater, and marine)means that we have no choice but to integrateconservation efforts with other human activities.

About one quarter of the worlds threatened specieslive outside protected areas, and most of the worldsterrestrial ecoregions fall significantly short of the10% protection target proposed by the IUCN


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Integrate conservation effortswith other human activities


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Disturbance may be reversible Second, evidence of historical recovery in areas

that once hosted high levels of human activityillustrates that while long-time scales are ofteninvolved, the biotic impacts of many types of

disturbance might not be completely irreversible.

The future of much of the worlds biodiversitydepends on the effective management of human-modified systems


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Outline





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Selectively logged forests As of 2005, approximately one third of the worlds

forestsa total of 1.3 billion hectares weredesignated primarily for timber production

Although all logging activity has a negative impacton the structure and composition of the forest, theseverity of this impact depends on the loggingintensity, including the number of trees removed perha, length of the rotation time, and sitemanagement practices.


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Selectively logged forests


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Selectively logged forests In the last few decades Reduced Impact Logging

(RIL) techniques have been developed that involvecareful planning and controlled harvesting

Different species groups exhibit significantlydifferent responses to logging impacts dependingon their life-history strategies and resourcerequirements.

Arboreal vertebrates appear to be particularly badlyaffected through the loss of nesting and food

resources; Butterflies are not affected


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Selectively logged forests Many best practice general guidelines could greatly

improve the value of logged forests for wildlife

Guidelines: the retention of structural complexity

(including dead wood), long-rotation times,maintenance of canopy cover, and fire control andtimber removal techniques.

Landscape scale measures: the designation of no-take areas, careful road design and maintenance oflandscape connectivity with intact corridors and

riparian buffers


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Outline





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Agroforestry Agroforestry is a summary term for practices that

involve the integration of trees and other woodyperennials into crop farming systems through theconservation of existing trees, their active plantingand tending, or the tolerance of naturalregeneration in fallow areas


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Agroforestry---two categories Complex agroforestry: an extension of the swidden

agriculture system where tree seedlings are co-planted with annual crops and left in fallow (e.g.rattan), or maintained in an annual-perennialassociation (e.g. damar-coffee). After 2550 yearsthe trees are felled and the cycle is repeated.

Home-gardens: small areas of agricultural land

located near to houses that are cultivated with amixture of annuals and perennials, including treesand shrubs. They are semi-permanent and typicallymore intensively managed than complex agroforests


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Agroforestry


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Agroforestry---benefits The provision of suitable habitat for forest species in

areas that have suffered significant historicaldeforestation

The provision of a landscape matrix that permits themovement of species among forest remnants

The provision of livelihoods for local people whichmay in turn relieve pressure on remaining areas ofprimary forest


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Agroforestry---biodiversity Although some species are invariably lost following

conversion of native habitat to agroforestry systems,a large proportion of the original fauna and flora ismaintained when compared to more intensifiedagricultural land-uses


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Outline





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Tree plantation Tree planting is the process of transplanting tree

seedlings, generally for forestry, land reclamation, orlandscaping purposes.


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Potential contribution to biodiversity They may more closely reflect the structural

complexity of native forest than many more intensiveproduction land-uses

They occupy a large area of once-forested land inmany parts of the world


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Potential contribution to biodiversity Some intensively managed plantation monocultures

offer very little value to biodiversity (e.g. oil palm inSoutheast Asia)

Complex multi-species plantations may providevaluable species habitat, even for some threatenedand endangered taxa


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Case study Brazilian Amazon A recent comprehensive study that utilized a quasi-

experimental landscape mosaic that resulted from alarge scale attempt to implement fast-growing treemonocultures in the Brazilian Amazon in the 1970s

In 2004, a large international team of researchersattempted to quantify the biodiversity that persists inprimary forests, 45 year old Eucalyptus plantations

and 1419 year old native second-growth


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Case study Brazilian Amazon


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Case study Brazilian Amazon Averaging across all taxa, secondary forests and

Eucalyptus plantations held only 59% and 47% ofthe species that were recorded in the old growthforests, respectively.

These results should be interpreted as a best casescenario, as many primary forest species wererecorded just once within the non-primary habitats

Removing these occasional species from the resultsreduces the estimated value of non-primary habitatsfor most taxa to an average of 46% of species for

second-growth and 39% for plantations.


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Case study Brazilian Amazon The estimated value of non-primary forests is much

higher for highly mobile taxa such as orchid bees,large mammals, and bats

More than 60% of the species of birds,grasshoppers and moths that were recorded insecondary forests were never recorded inold growth forests.

The species persisting in anthropogenic habitats canbe either composed of a subset of the species foundin primary forests, or from other habitats.


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Potential contribution to biodiversity The true conservation value of a plantation depends

upon the comparison with alternative land-uses thatmay otherwise exist in its place

There is a net loss of biodiversity if plantationsreplace native forest.

However, if plantations represent the lesser eviland prevent land from being converted to croplandsor pasture, or have been grown on areas ofdegraded land, then their importance for biodiversity

may be significant.


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Outline





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Growing population The human population is expected to increase from

6 billion today to 810 billion by 2050

Global demand for agricultural products is predicted

to grow even faster due to rising demand for foodand higher quality food (e.g. meat), as well as forbioenergy crops used in biofuel production

More agricultural land is needed


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Case study Oil palm The African oil palm is one of the worlds most

rapidly expanding crops, and has the highest yieldsand largest market share of all oil crops.

Cultivation has historically focused in Malaysia andIndonesia, oil palm is increasingly grown across thelowlands of other countries in Southeast Asia, Latin

America and Central Africa.


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Case study Oil palm

(a) areas of highest terrestrial vertebrate endemism; (b) globaldistribution of oil palm cultivation; (c) agriculturally suitable areas foroil palm; (d) oil palm-harvested area in Southeast Asia.


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Case study Oil palm

Each column contains a study of one taxon and shows the proportionof oil palm species shared and those not shared with forest. Onestudy of bees found fewer species in forests than oil palm, but mighthave underestimated forest species richness because the canopywas not sampled.


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Countryside biogeography Traditional thought: agricultural production will take

away land that would otherwise be used forbiodiversity conservation, and vice versa

Countryside biogeography: because a largeproportion of the planet is already dominated byhumans and what little remains of pristine habitatswill not be sufficient for the long-term survival of

many species, conservation planning should includemitigation measures that enable human activities toproceed with minimum displacement of nativespecies


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Countryside conservation Expand conservation strategy to include the

countryside: active and fallow agricultural plots,gardens and pasture, plantation or managed forest,and remnants of native vegetation in landscapesotherwise devoted primarily to human activities

About 50% or more of native birds, mammals, andinsects in Mesoamerica can survive in countryside,

though abundance of many species is low

d


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Countryside conservation 1. Species richness is considerably higher in the

vicinity of large remnants of relatively intact forest,suggesting that many species that occur in thecountryside can persist only in the nearby presenceof that native forest

2. The presence of native vegetation in human-dominated habitat facilitates persistence

3. The intensity of agriculture in a landscape isnegatively correlated with that landscapesconservation potential

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Urban areas Urbanization often irreversibly replaces natural

habitats with persistent artificial ones, resulting inlong-term impacts on many native species

Despite the rapid rate at which urban sprawl isoccurring worldwide, urban ecology has receivedrelatively little attention from conservation biologists

An Urbanizing Planethttp://www.youtube.com/watch?v=mPi4zwEpswE

C d Si
http://www.youtube.com/watch?v=mPi4zwEpswEhttp://www.youtube.com/watch?v=mPi4zwEpswE


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Case study Singapore Study of diversity in Singapore found that forest

reserves had higher species richness thansecondary forest fragments and urban manmadeparks

The larger areas of forest reserves and greaterfloristic complexity can sustain larger populations ofspecies with lower risks of extinction


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C d Si


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Case study SingaporeTwo key conservation lessons:

In highly urbanized tropical landscapes the leasthuman-disturbed land uses are likely also mostvaluable for preserving the native biodiversity, andshould therefore be given the highest conservationpriority

With a good understanding of the biology oforganisms, it is possible to enhance theconservation value of manmade habitats withinhuman modified landscapes

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Conservation and economyModified and degraded landscapes around the world

are not only of vital importance for biodiversityconservation, but are also home to millions of theworlds poorest people .

For impoverished communities biodiversity is aboutthe basic human needs of eating, staying healthy, andfinding shelter

Local people will ultimately decide the fate of theirlocal environments

C i d


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Conservation and economyHuman livelihoods and poverty concerns need to

receive high priority in the conservation agenda

Local guardians of modified landscapes have theright to develop management strategies that generatehigher economic returns that can raise them out ofpoverty

C ti d


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Conservation and economy

nov 14 conservation in human-modified landscapes

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