Chapter 56: Conservation BiologyAP BIOLOGY 2012

Conservation Biology

Conservation biology integrates: ecology, evolutionary biology, physiology, molecular biology, genetics, and behavioral ecology

Restoration Ecology - applies ecological principles to return degraded ecosystems to conditions as similar as possible to the natural state

Biodiversity Crisis

Tropical forests contain the greatest concentrations of species and are being destroyed at an ever increasing rate

Rates of species extinction are difficult to determine

The current rate is higher than in the recent past, and this is thought to be a result of human activities.

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Levels of Biodiversity

Three components

Genetic Diversity

Species Diversity

Ecosystem Diversity

Genetic diversity in a vole population

Species diversity in a coastal redwood ecosystem

Community and ecosystem diversity across the landscape of an entire region Fig. 56.3

Endangered vs. Threatened Species

Endangered species: a species in danger of becoming extinct throughout its range

Threatened species: species that are likely to become endangered in the foreseeable future

Hundred Heartbeat Club - Harvard biologist E. O. Wilson identified species with fewer than 100 individuals remaining

Philippine eagle

Javan rhinoceros

Yangtze River dolphin

Fig. 56.4

Benefits of Species Diversity

Many pharmaceuticals contain substances derived from plants

Loss of species results in a loss of genetic diversity

Loss of one species impacts other species (ex. bats as pollinators)

Fig 56.5

Fig. 56.6

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Ecosystem ServicesProcesses through which natural ecosystems and the species they contain help sustain human life

Purification of air and water

Detoxification and decomposition of wastes

Cycling of nutrients

Moderation of weather extremes

Pollination

Dispersal of seeds

Control of pests

Major Threats to Biodiversity

Habitat destruction (Habitat fragmentation)

Introduced species (Invasive species)

Over-exploitation (over-harvesting)

Disruption of interaction networks

(a) Brown tree snake

(b) Kudzu

Fig. 56.8

Population ConservationSmall-population Approach - study the processes that can cause very small populations finally to become extinct

Sensitive to positive feedback loop (extinction vortex)

Key factor that drives it is the loss of genetic variation necessary to enable evolutionary responses to environmental change

Small population

Genetic drift Inbreeding

Lower reproduction

Reduction in individual

fitness and population adaptability

Higher mortality

Loss of genetic

variability

Smaller population

Fig. 56.12

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Minimum Viable Population Size

Minimum Viable Population (MVP) - smallest population size at which a species is able to sustain its numbers and survive

Population Viability Analysis (PVA) - reasonably predict a population’s chances for survival (usually expressed as a specific probability of survival over a particular time)

Population ConservationDeclining-population Approach

Focuses on threatened and endangered populations that show a downward trend regardless of population size

Emphasizes the environmental factors that caused a population to decline in the first place

Requires that the population declines are evaluated on a case-by-case basis with a step-by-step conservation strategy

Steps for Analysis1. Confirm that the population is in decline

2. Study the species’ natural history

3. Develop hypotheses for all possible causes of decline

4. Test the hypotheses in order of likeliness

5. Apply the results of the diagnosis to manage for recovery

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Case Study: Red-Cockaded WoodpeckerRequire specific habitat factors for survival

Has been forced into decline by habitat destruction

Breeding cavities constructed and new breeding groups were formed

Once habitats were maintained and new breeding cavities were formed, the species began to rebound

Red-cockaded woodpecker

(a) Forests with low undergrowth (b) Forests with high, dense undergrowth

Fig.56.16

Sustaining LandscapesSustaining the region helps biodiversity of all ecosystems

Must understand past, present, and future patterns of landscape use to make biodiversity a part of land-use planning

Boundaries are defining features of landscapes

As fragmentation increases biodiversity tends to decrease

(a) Natural edges

(b) Edges created by human activity Fig. 56.16

Studies of Fragmented Forests

Two groups of species: those that live on the edge of the forest and those that live in the interior

Fig. 56.17

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Movement Corridor

Narrow strip of quality habitat connecting otherwise isolated patches

Humans sometimes create artificial corridors

Promote dispersal and help sustain populations Fig. 56.18

Establishing Protected AreasSlows the loss of biodiversity

Much of the focus is on hot spots (small areas with large concentrations of endemic species and large numbers of endangered and threatened species)

Good choices for nature reserves but identifying them is not always easy Terrestrial biodiversity

hot spots Marine biodiversity hot spots

Equator

Fig. 56.19

Nature ReservesExtensive reserves are important for far-ranging animals

Many cases the reserves are smaller than the actual area needed to sustain the population

Zoned reserves are established as conservation areas

Kilometers

100 0 50

WYOMING MONTANA

MONTANA

IDAHO

IDA

HO

W

YOM

ING

ne Sho sho R.

ows R.

Yell tone

Snake R.

Yellowstone National Park

Grand Teton National Park Biotic boundary for

short-term survival; MVP is 50 individuals.

Biotic boundary for long-term survival; MVP is 500 individuals.

Fig. 56.20

Nicaragua

Costa Rica

CARIBBEAN SEA

PACIFIC OCEAN

National park land Buffer zone

Pan a

ma

(a) Zoned reserves in Costa Rica

(b) Tourists in one of Costa Rica’s zoned reserves

Fig. 56.21

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Nutrient EnrichmentCritical load - amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity

If nutrients exceed critical load, they will leach into groundwater and runoff into aquatic ecosystems

Fig. 56.23

Winter Summer

Fig. 56.24

ToxinsBiological Magnification - retained substances become more concentrated with each successive step up in trophic level

Some toxins accumulate in body tissues

DDT

PCBs

Herring gull eggs 124 ppm

Lake trout 4.83 ppm

Smelt 1.04 ppm

Phytoplankton 0.025 ppm

Zooplankton 0.123 ppm

Con

cent

ratio

n of

PC

Bs

Fig. 56.25

Greenhouse Gasses

Increase in the concentration of atmospheric CO2

Year

CO2

Temperature

CO

2 con

cent

ratio

n (p

pm)

Ave

rage

glo

bal t

empe

ratu

re (°

C)

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

390

380

370

360

350

340

330

320

310

300

14.9

14.8

14.7

14.6

14.5

14.4

14.3

14.2

14.1

14.0

13.9

13.8

13.7

13.6

Figure 56.27

Fig. 56.27

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CO2 and Forest Ecology

Forest-Atmosphere Carbon Transfer and Storage (FACTS-I) Experiment (1995)

How does elevated CO2 influence tree growth, carbon concentration in soils, insect populations, soil moisture, and growth of plants?

Fig. 56.28

Depletion of Atmospheric OzoneEarth is protected from UV rays by the Ozone layer

Thinning caused mainly by CFCs

350

300

250

200

150

100

0

Year

Ozo

ne la

yer t

hick

ness

(Dob

sons

)

1955 ‘60 ‘65 ‘70 ‘75 ‘80 ‘85 ‘90 ‘95 2000 ‘05 ‘10

Chlorine atom

Sunlight

Chlorine

O2

CI2O2

O2

CIO

CIO

O3

Fig. 56.29 - 56.30

September 1979 September 2009

Acid Precipitation

Burning of organic matter releases oxides of sulfur and nitrogen that react with water to form sulfuric acid and nitric acid

Acids fall with precipitation (pH less than 5.6)

Impacts aquatic pH and soil chemistry

4.6

4.6

4.3

4.1

4.3

4.6

4.6 4.3

Europe

North America

Field pH

≥5.3

5.2–5.3

5.1–5.2

5.0–5.1

4.9–5.0

4.8–4.9

4.7–4.8

4.6–4.7

4.5–4.6

4.4–4.5

4.3–4.4

<4.3

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