Chapter 10Biodiversity

10.1 What is biodiversity?10.2 Biodiversity at risk10.3 The future of biodiversity

Biodiversity – the variety of living things in an area;

Three levels of biodiversity:

1. Genetic diversity

2. Species diversity

3. Ecosystem diversity

When we talk about “biodiversity of the earth,” we usually mean species diversityGuess the number of species on the planet?Latest estimate: 8.7 million species

From Science Daily: “Furthermore, the study, published byPLoS Biology, says a staggering 86% of all species on land and 91% of those in the seas have yet to be discovered, described and catalogued.”

Benefits of Biodiversity

1. Biodiversity can affect the stability of ecosystems

When even one species is lost, it affects the entire ecosystem

Keystone species – species that are critical to the survival of an entire ecosystem

Example: sea otter

Benefits of Biodiversity

2. Healthy ecosystems provide good ecosystem services – the benefits that people obtain from ecosystems

Ecosystem Services: the benefits people obtain from ecosystems

RegulatingBenefits obtained from

regulation of ecosystem processes

• climate regulation• disease regulation

• flood regulation

ProvisioningGoods produced or provided

by ecosystems• food

• fresh water• fuel wood

• genetic resources

CulturalNon-material benefits from

ecosystems• spiritual

• recreational • aesthetic

• inspirational• educational

SupportingServices necessary for production of other ecosystem services

• Soil formation• Nutrient cycling

• Primary production

Benefits of Biodiversity

3. Humans need biodiversity for medical, industrial, and agricultural purposes

(existing uses and genetic information for new uses)

Foxglove

Digitalis purpurea, EuropeDigitalis for heart failure

Pacific yew

Pacific NorthwestOvarian cancer

Potential new food crops may be lost forever

Source: FAO

4. Ethics, aesthetics, and recreationE.O. Wilson: there is “spiritual, religious and

psychological value” in preserving biodiversity

Ecotourism – tourism that supports conservation and sustainable development of ecologically unique areas

Extinction – three types:

Local – species is extinct in one area, but still found in other locations

Ecological – so few left that it no longer plays its ecological role in the communities in which it is found

Biological extinction – completely gone from the planet

Biodiversity at Risk

Extinction is a natural process

• Extinction is irreversible: once a species is lost, it is lost forever

• 99.9% of all species that ever existed are now extinct

Earth has had five mass extinctions so far

Background extinction rate •“normal” rate of extinction that occurs naturally • background extinctions are usually unrelated • for example one estimate gives the background extinction rate for birds as 1 species lost per 400 yearsMass extinction events • when 50-95% of all species go extinct in a relatively short period of time• five events in Earth’s history have killed off massive numbers of species at once

Mass extinctions

• Biggest: end of Permian (250mya), loss of 95% of species• Most recent: K-T event at end of Cretaceous (65mya), asteroid struck

earth, led to extinction of dinosaurs

Extinction rates

Humans profoundly affect rates of extinction (causing 100 to 1000 extinctions per million species instead of the background extinction rate of 1-5 species per million)

Estimated annual extinction rate before humans: 0.0001%

Estimated annual extinction rate since humans: 0.1-1%

Scientists think that we are in the 6th mass extinction and this time, it is due to human activity

Passenger pigeon

Great auk Dodo Dusky seaside sparrow

Aepyornis(Madagascar)

Extinct species – due to human activities

Think about this…

Name some characteristics of species that make them especially likely to go extinct:

List is on the next slide….

Characteristic Examples

Low reproductive rate(K-strategist)

Specialized niche

Narrow distribution

Feeds at high trophic level

Fixed migratory patterns

Rare

Commercially valuable

Large territories

Blue whale, giant panda,rhinoceros

Blue whale, giant panda,Everglades kite

Many island species,elephant seal, desert pupfish

Bengal tiger, bald eagle,grizzly bear

Blue whale, whooping crane,sea turtles

Many island species,African violet, some orchids

Snow leopard, tiger, elephant, rhinoceros, rare plants and birds

California condor, grizzly bear, Florida panther

These are characteristics that increase the risk of extinction, along with examples of each

How do humans cause extinction?HIPPCO

1. Habitat destruction – may be complete destruction or habitat fragmentation

Habitat destruction is the number one threat to biodiversity

How do humans cause extinction?HIPPCO

2. Introduction of invasive species

Example: Mites, called Verroa destructor, introduced from Asia have seriously reduced the wild honeybee population in the U.S.

1918

2000

Spread of fire ants

Kudzu

• Fast-growing climbing vine from Asia

• Introduced to control erosion

European Starling• Released into New York

City in the late1800’s by a man who wanted to introduce to the U.S. all of the birds mentioned in Shakespeare

• Now widespread across North America

• Outcompetes many native birds, such as bluebirds, for nest holes

How do humans cause extinction?HIPPCO

3. Population growth – root of the problem?

Food for thought: What native species could live in these conditions?

How do humans cause extinction?HIPPCO

4. Pollution

Example: Use of DDT almost caused the extinction of the Bald Eagle and other predatory birds

Biomagnification

Also called biological magnification

Accumulation of pollutants in higher order trophic levels

How do humans cause extinction?HIPPCO

5. Climate change

polar bear – loss of sea ice bleaching of coral reefs

• Golden toads were discovered in 1964, in Monteverde, Costa Rica

• The mountainous cloud forest has a perfect climate for amphibians

• Extreme sexual dimorphism• Unfortunately, they became

extinct within 25 years • Causes: 1. Changes in habitat – drying of cloud

forest due to global warming, ENSO

2. Narrow window of time for reproduction – breed in temporary ponds which dried up early

3. Limited range

4. Disease Female

Males

How do humans cause extinction?HIPPCO

6. Overharvesting, hunting, poaching

Both legal and illegal collecting of organisms has had a negative impact

Areas of Critical Biodiversity

Biodiversity “hotspots”

1. High numbers of endemic species – means many organisms that live there are not found anywhere else in the world

2. Threatened by human activities

•Tropical rainforests•Coral reefs and coastal ecosystems•Islands

Global Biodiversity Hotspots

Concentration of rare species

Low Moderate High

Top Six Hot Spots

1 Hawaii2 San Francisco Bay area3 Southern Appalachians4 Death Valley5 Southern California6 Florida Panhandle

4

5

2

6

3

1

U.S. Biodiversity Hotspots

Efforts to Preserve Biodiversity

1. Efforts to save individual species

• Captive-breeding programs – California condor population went from 9 in 1986 to 58 in 2002

• Zoos, aquariums, parks, gardens – for many, there is now more emphasis on preservation and less on entertainment

• Gene banks and seed banks

Efforts to Preserve Biodiversity

2. Efforts to save habitats and ecosystems - more effective to save biodiversity this way (rather than focusing on one species); It is important to save the entire ecosystem, not just an isolated species

Example: Vermillion Darter

The vermilion darter is found only in the Turkey Creek drainage, a tributary of the Locust Fork of the Black Warrior River, Jefferson County, Alabama.

Efforts to Preserve BiodiversityIn Alabama, Forever Wild Land Trust acquires land that will be used for wildlife management areas, nature reserves, state parks and recreational areas

Provides areas of habitat for many species

Efforts to Preserve Biodiversity

3. Legal protection – exists in many countriesU.S. has Endangered Species Act (ESA), passed in 1973Main Provisions:• U.S. Fish and Wildlife Service (USFWS) compiles a list of

endangered and threatened species on land and in freshwater, National Marine Fisheries Service (NMFS) is responsible for marine species

• End./Thr. Species may not be killed, caught, sold (penalties include fines and jail, enforced mainly by USFWS, also Coast Guard)

• Fed. Govt. may not carry out projects that jeopardize listed species

• Dept. of Interior should designate and protect critical habitat necessary for survival of listed species

• USFWS must develop a recovery plan for each listed species

ESA terminologyEndangered species – a species that is likely to become extinct

unless some protective measures are enacted immediately

Threatened species – species with declining populations, likely to become endangered if not protected

Critical habitat – areas that are critical to the conservation of the species, may be where it lives or where it migrates

Alabama endangered species:

Green pitcher plant

Watercress darter

Gopher tortoise

Gray bat

Green sea turtle

Red-cockaded woodpecker

Successful recoveries• Species which increased in population size since being placed on the endangered list

include:• Bald Eagle (increased from 417 to 11,040 pairs between 1963 and 2007); removed

from list 2007 • Whooping Crane (increased from 54 to 436 birds between 1967 and 2003) • Kirtland's Warbler (increased from 210 to 1,415 pairs between 1971 and 2005) • Peregrine Falcon (increased from 324 to 1,700 pairs between 1975 and 2000);

removed from list • Gray Wolf (populations increased dramatically in the Northern Rockies, Southwest,

and Great Lakes) • Gray Whale (increased from 13,095 to 26,635 whales between 1968 and 1998);

removed from list • Grizzly bear (increased from about 271 to over 580 bears in the Yellowstone area

between 1975 and 2005); removed from list 3/22/07 • California’s Southern Sea Otter (increased from 1,789 in 1976 to 2,735 in 2005) • San Clemente Indian Paintbrush (increased from 500 plants in 1979 to more than

3,500 in 1997) • Red Wolf (increased from 17 in 1980 to 257 in 2003) • Florida's Key Deer (increased from 200 in 1971 to 750 in 2001) • Hawaiian Goose (increased from 400 birds in 1980 to 1,275 in 2003) • (increased from 3,500 in 1979 to 18,442 in 2004)

Controversy over ESA

• How successful has it been?• Does it trample individual rights by

prohibiting certain uses of critical habitat owned by private citizens (limits on logging, mining, development, etc.)?

• Does it hinder economic development by such prohibitions?

Efforts to Preserve Biodiversity

4. International efforts

IUCN – International Union for the Conservation of Nature and Natural Resources; organization that publishes the “red list” of endangered species, promotes preservation of species and habitats (http://www.iucnredlist.org/)

CITES treaty – first effort to stop killing of African elephants for ivory tusks, prohibits trade of many species

Efforts to Preserve Biodiversity

5. Private organizations

Examples: World Wildlife Fund, Nature Conservancy, Greenpeace International

Freshwater Land Trust– in Alabama, buys land to enhance water quality and preserve natural areas