Chapter 18

Conservation of BiodiversityMonday, May 16, 16

The 6th Mass Extinction

© Extinction- when there are no longer any of the species in the world.

© We are currently losing approximately 50,000 species per year.

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Genetic Diversity

© Scientists want to conserve genetic diversity so that the species can survive environmental change and inbreeding will not occur.

© Inbreeding occurs when individuals with similar genotypes, generally relatives, breed with each other.

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Categories of Endangerment

© Extinct- no known species exist today© Threatened- species with a high risk of

extinction in the future© Near-threatened- species that are likely to

become threatened in the future© Least concern- species are widespread and

abundant

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Global Extinction

Ø Some animals have become prematurely extinct because of human activities.

Figure 11-2Monday, May 16, 16

Endangered and Threatened Species: Ecological Smoke Alarms

Ø Endangered species: so few individual survivors that it could soon become extinct.

Ø Threatened species: still abundant in its natural range but is likely to become endangered in the near future.

Figure 11-3Monday, May 16, 16

Fig. 11-3, p. 224

Hawksbill sea turtle

Giant panda Black-footed ferret

Whooping crane

Northern spotted owl

Blue whale

Mountain gorilla Florida panther

California condor

Black rhinoceros

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Fig. 11-4, p. 225

Low reproductive rate(K-strategist)

Specialized niche

Narrow distribution

Feeds at high trophic level

Fixed migratory patterns

Rare

Commercially valuable

Large territories

Characteristic

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

Examples

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HIPCO

© H- Habitat Loss© I- Invasive Species© P- Pollution© C- Climate

Change© O- Overharvested

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Habitat Loss© For most species the greatest cause of decline and

extinction is habitat loss.© Most habitat loss is due to human development

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Types of Forests

Ø Old-growth forest: uncut or regenerated forest that has not been seriously disturbed for several hundred years.l 22% of world’s forest.l Hosts many species with

specialized niches.

Figure 10-5Monday, May 16, 16

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Types and Effects of Forest Fires

Ø Depending on their intensity, fires can benefit or harm forests.l Burn away flammable ground material.l Release valuable mineral nutrients.

Figure 10-13Monday, May 16, 16

Solutions: Controversy Over Fire ManagementØ To reduce fire damage:

l Set controlled surface fires.l Allow fires to burn on public lands if they don’t

threaten life and property. l Clear small areas around property subject to fire.

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Why Should We Care about the Loss of Tropical Forests?

Ø About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests.

Figure 10-18Monday, May 16, 16

Invasive Species

© Alien species (exotic species)- species that live outside their historical range.

© Invasive species- when alien species spread rapidly across large areas.

© Ex- Kudzu Vine, Zebra Mussel, Silver Carp

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INVASIVE SPECIES

Ø Many invasive species have been introduced intentionally.

Figure 11-11Monday, May 16, 16

INVASIVE SPECIES

Ø Many invasive species have been introduced unintentionally.

Figure 11-11Monday, May 16, 16

INVASIVE SPECIES

Ø Hydrilla in Arkansas

Solution?Pakistani Fly

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Fig. 11-13, p. 236

• Climate similar to habitat of invader

• Absence of predators on invading species

• Early successional systems

• Low diversity of native species

• Absence of fire

• Disturbed by human activities

Characteristics ofSuccessful

Invader Species

• High reproductive rate, short generation time (r-selected species)

• Pioneer species

• Long lived

• High dispersal rate

• Release growth-inhibiting chemicals into soil

• Generalists

• High genetic variability

Characteristics ofEcosystems Vulnerable

to Invader Species

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Fig. 11-14, p. 236

• Do not allow wild animals to escape.

• Do not spread wild plants to other areas.

• Do not dump the contents of an aquarium into waterways, wetlands, or storm drains.

• When camping use wood near your campsite instead of bringing firewood from somewhere else.

• Do not dump unused bait into the water.

• After dogs visit woods or the water brush them before taking them home.

• After each use clean your vehicle, mountain bike, surfboard, kayaks, canoes, boats, tent, hiking boots, and other gear before heading for home.

• Empty all water from canoes, kayaks, dive gear, and other outdoor equipment before heading home.

• Plant a variety of trees, shrubs, and other plants in your yard to reduce losses from invasive species.

• Do not buy plants from overseas or swap them with others using the Internet.

What Can You Do?

Invasive Species

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Pollution

© Threats to biodiversity can come from toxic contaminants such as pesticides, heavy metals, acids, and oil spills.

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PollutionØ Each year pesticides:

l Kill about 1/5th of the U.S. honeybee colonies.

l 67 million birds.l 6 -14 million fish.l Threaten 1/5th of the

U.S.’s endangered and threatened species.

Example of biomagnification of DDT in an aquatic food chain.

Figure 11-15Monday, May 16, 16

Fig. 11-15, p. 237

DDT in water 0.000003 ppm, or 3 ppt

DDT in fish-eating birds (ospreys)

25 ppm

DDT in large fish (needle fish) 2 ppm

DDT in small fish (minnows) 0.5 ppm

DDT in zooplankton 0.04 ppm

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Climate Change

© The concern is how climate change will affect temperature and precipitation around the world, and how this will impact biodiversity.

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Overharvesting© When individuals of a species are removed at a rate

faster than the population can replace them.© Ex- dodo, American bison, passenger pigeon.

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OVEREXPLOITATION

Ø Some protected species are killed for their valuable parts or are sold live to collectors.

Ø Killing predators and pests that bother us or cause economic losses threatens some species with premature extinction.

Ø Legal and illegal trade in wildlife species used as pets or for decorative purposes threatens some species with extinction.

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Overfishing and Extinction: Gone Fishing, Fish Gone

Ø About 75% of the world’s commercially valuable marine fish species are over fished or fished near their sustainable limits.l Big fish are becoming scarce.l Smaller fish are next.l We throw away 30% of the fish we catch.l We needlessly kill sea mammals and birds.

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Fig. 12-A, p. 255

Fish farming in cage

Trawler fishing

Spotter airplane

Sonar

Trawl flapTrawl lines

Purse-seine fishing

Trawl bagFish school

Drift-net fishingLong line fishing

Lines with hooks

Fish caught by gills

Deep sea aquaculture cage

Float Buoy

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Lacey Act

© One  of  the  earliest  laws  in  the  U.S.  to  control  the  trade  of  wildlife.

© First  passed  in  1900,  the  act  prohibited  the  transport  of  illegally  harvested  game  animals,  primarily  birds  and  mammals,  across  state  lines.    

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CITES

© Convention on International Trade in Endangered Species of Wild Fauna and Flora

© Developed in 1973 to control the international trade of threatened plants and animals.

© Today, CITIES is an international agreement between 175 countries of the world.

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Red List

© The IUCN keeps a list of threatened species, known as the red list.

© Each country has its own way to monitor and regulate the import and export of animals on the list.

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Conservation Legislation© Marine Mammal Protection Act- prohibits the

killing of all marine mammals in the U.S. and prohibits the import or export of any marine mammal body parts.

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Endangered Species Act

© Endangered Species Act- first passed in 1973, it authorizes the U.S. Fish and Wildlife Service to determine which species can be listed as threatened or endangered and prohibits the harming of these species.

© Trading these species is also illegal.© The act also authorizes the government to

purchase habitat that is critical to the species.

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Convention on Biological Diversity

© In 1992, nations came together and made a treaty to protect biodiversity.

© The treaty had three objectives: conserve biodiversity, sustainably use biodiversity, and equitably share the benefits that emerge from the commercial use of genetic resources such as pharmaceutical drugs.

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Size, Shape and Connectedness

© When designing and managing protected areas we must consider how close to another area they should be, how large the area is, and the amount of edge habitat the area contains.

© Edge habitat- the area where two different communities come together, typically forming an abrupt transition. Ex. A grassy field meeting a forest.

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Biosphere Reserves

© Protected areas consisting of zones that vary in the amount of permissible human impact.

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NATURE RESERVESØ Large and medium-sized reserves with buffer

zones help protect biodiversity and can be connected by corridors.

Ø Costa Rica has consolidated its parks and reserves into 8 megareserves designed to sustain 80% if its biodiversity.

Figure 10-10BMonday, May 16, 16

Fig. 10-B, p. 213

Cordillera Volcanica Central

Pacific Ocean

CostaRica

Caribbean SeaNigaragua

Panama

La Amistad

Llanuras deTortuguero

Guanacaste

Arenal

BajoTempisque

Peninsula Osa

Pacifico Central

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