CHAPTER 38Conservation Biology

Saving the Tiger Tigers once roamed across Asia The arrival of humans brought competition for food, and

also hunters Tiger trophies, claws and bones are worth a lot of money Poor people in the region are invading tiger habitat to

make ends meet

Myanmar tiger photographed by a remote “camera trap”

Conservation effortsproviding protection for tigers so their populations can increase

The efforts to save tigers

Reflect a worldwide struggle to preserve biodiversity, the diversity of living things

Tiger populations have declined from over 100,00 to fewer than 5,000 in the wild

We are now presiding over a biodiversity crisisA rapid decrease in Earth’s great variety of organisms

Conservation biologyIs a goal-driven science that seeks to counter the biodiversity crisis

THE BIODIVERSITY CRISIS: AN OVERVIEW

38.1 Human activities threaten Earth’s biodiversityBiodiversity includes

1. Genetic diversity, within and between populations

2. Species diversity3. Ecosystem diversity

We are experiencing a mass extinction

Named 1.8 million species 10-200 million species exist on Earth Current global extinction rate is 1,000

times higher than any time in the past 100,000 years.

Over half of the current plant and animal species will be extinct by the end on the 21st century

WE ARE EXPERIENCING A MASS EXTINCTION About 12% of the 9,946 known bird

species and 24% of the 4,763 known mammalian species are threatened with extinction

About 20% of the known freshwater fishes in the world have either become extinct in recent history or are threatened with extinction

Of the 20,000 known plant species in the US, 200 have become extinct since we started keeping records and 730 species are endangered or threatened

Human activities effect

Important ecosystem processes:

1. Trophic structure2. Energy flow3. Chemical cycling4. Natural

disturbances

WHY SHOULD WE CARE?

38.2 Biodiversity is vital to human welfare Intrinsic Value Biophilia Moral beliefs Food Fiber Medicines (25%) ecosystem services (O2, fertile soil) 33 TRILLION USD vs 18 TRILLION global

GNP

38.3 Habitat destruction, introduced species, and overexploitation are the major threats to biodiversity

Human Alteration of Habitat: Poses single greatest threat to

biodiversityAgricultureMiningUrban developmentForestryEnvironmental pollution

Introduced Species Can disrupt communities by competing with

or preying on native species Ex) Kudzo EX) Lake Victoria’s Nile Perch Hitchhiking seeds or insects, escaped exotic

pets, species transported as unknown “cargo”, agriculture or ornamentation

50,000 in US costing over 130 BILLION in damages and control efforts

Overexploitation of wildlife by harvesting Has threatened various animal and plant

species Rates of harvesting exceed the ability of

the populations to rebound Commercial Harvest Poaching Sport Hunting Illegal trade Whales, tigers, American bison, Galapagos

tortoises, and numerous fishes (NA bluefin tuna)

38.4 Pollution of the environment compounds our impact on other species

Effects of pollution includeAcid rainozone depletioneutrophicationdead zones

Chemical pesticidesAre concentrated by biological magnification

Herringgull eggs124 ppm

Lake trout4.83 ppm

Smelt1.04 ppm

Zooplankton0.123 ppm

Phytoplankton0.025 ppm

Con

cent

ratio

n of

PC

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38.5 Rapid global warming could alter the entire biosphereBurning of fossil fuelsIs increasing the amount of CO2 and other

greenhouse gases in the airThe increase of these gases in the atmosphereMay lead to global warming

EXTRA CREDIT: Watch An Inconvenient Truth

Write an essay about it: 2pgs double spaced

20 points!

CO

2 co

ncen

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(ppm

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Tem

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390

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1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

1.05

0.90

0.75

0.60

0.45

0.30

0.15

0

–0.15

–0.45

–0.30

Temperature

CO2

Year

Global warming:CO2 lets sunlight throughbut retains the heatradiated from Earth.

CO2 in theatmosphere

Human activities and naturalprocesses add CO2 to theatmosphere, increasing the effect.

Photosynthesis removesCO2 from the atmosphere,decreasing the effect.

CO2

CO2 CO2

Global warming may Change climate patterns, melt polar ice

caps, flood coastal regions Increase the rate of species loss

38.6 Two ways to study endangered populations are:

The small-population approach The declining-population approach Habitat degradation Often fragments populations, causing their numbers

to decline WHY?

The small-population approach Identifies the minimum viable

population size and focuses on preserving genetic variation

Extinction Vortex Loss of genetic variation How small is too small? Population Viability Analyses DEPENDS!

The declining-population approach Diagnoses and treats the causes of a

population’s decline Proactive Strategy1. Confirm species is in decline2. Study natural history3. Develop hypotheses for all possible

causes for decline4. Test most likely first 5. Apply results to management

strategies

38.7 Identifying critical habitat factors can guide conservation effortsPreserving critical habitatMay help endangered species recover

Conflicts may ariseBetween habitat preservation and

resource use by humans

Example: red-cockaded woodpecker NEEDS:

mature pine forests Dominated by long-leaf pines Low growth around trees

Destruction of forests fire management in what is left

Management Strategies:Protection of long-leaf pine forestUse of controlled burnsCreated nest cavities in unoccupied areas

for dispersal into new areas Single-Species Management

Can negatively effect other speciesEx) Migratory birdsTested managed vs. non-managed habitats

and compared bird speciesManaged areas had enhanced populations

of ALL bird species not just the woodpecker

Near extinction to a sustainable population