chapter 11 sustaining biodiversity: the species approach

Chapter 11Chapter 11

Sustaining Biodiversity: Sustaining Biodiversity: The Species ApproachThe Species Approach

Core Case Study: Core Case Study: The Passenger Pigeon - Gone The Passenger Pigeon - Gone

ForeverForever Once the most Once the most

numerous bird on earth.numerous bird on earth. In 1858, Passenger In 1858, Passenger

Pigeon hunting became Pigeon hunting became a big business.a big business.

By 1900 they became By 1900 they became extinct from over-extinct from over-harvest and habitat harvest and habitat loss.loss.

Figure 11-1Figure 11-1

SPECIES EXTINCTIONSPECIES EXTINCTION

Species can become extinct: Species can become extinct: LocallyLocally: A species is no longer found in an area : A species is no longer found in an area

it once inhabited but is still found elsewhere in it once inhabited but is still found elsewhere in the world.the world.

EcologicallyEcologically: Occurs when so few members of a : Occurs when so few members of a species are left they no longer play its ecological species are left they no longer play its ecological role.role.

Globally (biologically)Globally (biologically): Species is no longer : Species is no longer found on the earth.found on the earth.

Global ExtinctionGlobal Extinction

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


Endangered and Threatened Species: Endangered and Threatened Species: Ecological Smoke AlarmsEcological Smoke Alarms

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

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


Fig. 11-3, p. 224

Some species Some species have have characteristics characteristics that make them that make them vulnerable to vulnerable to ecological and ecological and biological biological extinction.extinction.

SPECIES SPECIES EXTINCTIONEXTINCTION



Scientists use measurements and models to Scientists use measurements and models to estimate extinction rates.estimate extinction rates. The International Union for the Conservation of The International Union for the Conservation of

Nature and Natural Resources (IUCN) publishes Nature and Natural Resources (IUCN) publishes an annual an annual Red List, listing the world, listing the world’’s threatened s threatened species.species.

The 2013 Red List contains approximately The 2013 Red List contains approximately 20,000 species at risk for extinction.20,000 species at risk for extinction.


http://www.iucnredlist.org/


Percentage of various species types Percentage of various species types threatened with premature extinction from threatened with premature extinction from human activities.human activities.


IMPORTANCE OF WILD SPECIES IMPORTANCE OF WILD SPECIES We should not cause the premature We should not cause the premature

extinction of species because of the extinction of species because of the economic and ecological services they economic and ecological services they provide.provide.

Some believe that each wild species has an Some believe that each wild species has an inherent right to exist.inherent right to exist. Some people distinguish between the survival Some people distinguish between the survival

rights among various types of species (plants vs. rights among various types of species (plants vs. animals).animals).

HABITAT LOSS, DEGRADATION, HABITAT LOSS, DEGRADATION, AND FRAGMENTATIONAND FRAGMENTATION

Conservation biologists summarize the most Conservation biologists summarize the most important causes of premature extinction as important causes of premature extinction as ““HIPPOHIPPO””: : Habitat destruction, degradation, and Habitat destruction, degradation, and

fragmentationfragmentation Invasive speciesInvasive species Population growthPopulation growth PollutionPollution OverconsumptionOverconsumption

Fig. 11-8a, p. 230

Range 100 years ago

Indian Tiger

Range today(about 2,300 left)

Fig. 11-8b, p. 230

Range in 1700

Black Rhino

Range today(about 3,600 left)

Fig. 11-8c, p. 230

Probable range 1600

African Elephant

Range today

Fig. 11-8d, p. 230

Range today(34,000–54,000 left)

Asian or Indian Elephant

Former range

Case Study: Case Study: A Disturbing Message from the BirdsA Disturbing Message from the Birds

The majority of the The majority of the worldworld’’s bird species s bird species are found in South are found in South America.America. Threatened with habitat Threatened with habitat

loss and invasive loss and invasive species.species.


INVASIVE SPECIESINVASIVE SPECIES

Many nonnative Many nonnative species provide us species provide us with food, medicine, with food, medicine, and other benefits and other benefits but a a few can wipe but a a few can wipe out native species, out native species, disrupt ecosystems, disrupt ecosystems, and cause large and cause large economic losses.economic losses.

Kudzu vine was introduced in Kudzu vine was introduced in the southeastern U.S. to the southeastern U.S. to control erosion. It has taken control erosion. It has taken over native species habitats.over native species habitats.

Figure 11-AFigure 11-A

INVASIVE INVASIVE SPECIESSPECIES

Prevention is the Prevention is the best way to reduce best way to reduce threats from threats from invasive species, invasive species, because once they because once they arrive it is almost arrive it is almost impossible to slow impossible to slow their spread.their spread.


OVEREXPLOITATIONOVEREXPLOITATIONOVERCONSUMPTIONOVERCONSUMPTION

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

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

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

Myanmar Animal Trade

OVEREXPLOITATIONOVEREXPLOITATIONOVERCONSUMPTIONOVERCONSUMPTION

Rhinoceros are often Rhinoceros are often killed for their horns killed for their horns and sold illegally on and sold illegally on the black market for the black market for decorative and decorative and medicinal purposes.medicinal purposes.


Case Study: Case Study: Rising Demand for Bushmeat in AfricaRising Demand for Bushmeat in Africa

Bushmeat Bushmeat hunting has hunting has caused the local caused the local extinction of extinction of many animals in many animals in West Africa.West Africa.

Can spread Can spread disease such as disease such as HIV/AIDS and HIV/AIDS and ebola virus.ebola virus.


PROTECTING WILD SPECIES: PROTECTING WILD SPECIES: LEGAL AND ECONOMIC LEGAL AND ECONOMIC

APPROACHESAPPROACHES International treaties have helped reduce the International treaties have helped reduce the

international trade of endangered and international trade of endangered and threatened species, but enforcement is threatened species, but enforcement is difficult.difficult. One of the most powerful is the 1975 Convention One of the most powerful is the 1975 Convention

on International Trade of Endangered Species on International Trade of Endangered Species (CITES).(CITES).• Signed by 169 countries, lists 900 species that cannot Signed by 169 countries, lists 900 species that cannot

be commercially traded.be commercially traded.

Case Study: Case Study: The U.S. Endangered Species ActThe U.S. Endangered Species Act

One of the worldOne of the world’’s most far-reaching and s most far-reaching and controversial environmental laws is the 1973 controversial environmental laws is the 1973 U.S. Endangered Species Act (ESA).U.S. Endangered Species Act (ESA). ESA forbids federal agencies (besides defense ESA forbids federal agencies (besides defense

department) to carry out / fund projects that department) to carry out / fund projects that would jeopardize an endangered species.would jeopardize an endangered species.

ESA makes it illegal for Americans to engage in ESA makes it illegal for Americans to engage in commerce associated with or hunt / kill / collect commerce associated with or hunt / kill / collect endangered or threatened species.endangered or threatened species.

Case Study: Case Study: The U.S. Endangered Species ActThe U.S. Endangered Species Act

Biodiversity hotspots in relation to the largest Biodiversity hotspots in relation to the largest concentrations of rare and potentially concentrations of rare and potentially endangered species in the U.S.endangered species in the U.S. Figure 11-18Figure 11-18

Endangered SpeciesEndangered Species

Because of Because of scarcity of scarcity of inspectors, inspectors, probably no probably no more than 1/10more than 1/10thth of the illegal of the illegal wildlife trade in wildlife trade in the U.S. is the U.S. is discovered.discovered.


Endangered SpeciesEndangered Species

Congress has amended the ESA to help Congress has amended the ESA to help landowners protect species on their land.landowners protect species on their land.

Some believe that the ESA should be Some believe that the ESA should be weakened or repealed while others believe it weakened or repealed while others believe it should be strengthened and modified to should be strengthened and modified to focus on protecting ecosystems.focus on protecting ecosystems.

Many scientists believe that we should focus Many scientists believe that we should focus on protecting and sustaining biodiversity and on protecting and sustaining biodiversity and ecosystem function as the best way to ecosystem function as the best way to protect species.protect species.

How Would You Vote?How Would You Vote?

To conduct an instant in-class survey using a classroom response To conduct an instant in-class survey using a classroom response system, access system, access ““JoinIn Clicker ContentJoinIn Clicker Content”” from the PowerLecture main from the PowerLecture main menu for Living in the Environment. menu for Living in the Environment.

Should the Endangered Species Act be Should the Endangered Species Act be modified to protect and sustain the nation's modified to protect and sustain the nation's overall biodiversity?overall biodiversity? a. No. Protecting entire habitats will only further a. No. Protecting entire habitats will only further

interfere with the rights of landowners.interfere with the rights of landowners. b. Yes. Protecting endangered habitats is more b. Yes. Protecting endangered habitats is more

efficient and effective than saving individual efficient and effective than saving individual species.species.

PROTECTING WILD SPECIES: THE PROTECTING WILD SPECIES: THE SANCTUARY APPROACHSANCTUARY APPROACH

Gene banks, botanical gardens and using Gene banks, botanical gardens and using farms to raise threatened species can help farms to raise threatened species can help prevent extinction, but these options lack prevent extinction, but these options lack funding and storage space.funding and storage space.

Zoos and aquariums can help protect Zoos and aquariums can help protect endangered animal species by preserving endangered animal species by preserving some individuals with the long-term goal of some individuals with the long-term goal of reintroduction, but suffer from lack of space reintroduction, but suffer from lack of space and money. and money.

RECONCILIATION ECOLOGYRECONCILIATION ECOLOGY

Reconciliation ecology involves finding ways Reconciliation ecology involves finding ways to share places we dominate with other to share places we dominate with other species.species. Replacing monoculture grasses with native Replacing monoculture grasses with native

species.species. Maintaining habitats for insect eating bats can Maintaining habitats for insect eating bats can

keep down unwanted insects.keep down unwanted insects. Reduction and elimination of pesticides to protect Reduction and elimination of pesticides to protect

non-target organisms (such as vital insect non-target organisms (such as vital insect pollinators).pollinators).

chapter 11 sustaining biodiversity: the species approach

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