Chapter 11 Sustaining Biodiversity: The Species Approach

Core Case Study: The Passenger Pigeon - Gone Forever  Once the most numerous bird on earth.  In 1858, Passenger Pigeon hunting became a big business.  By 1900 they became extinct from over- harvest and habitat loss. Figure 11-1

SPECIES EXTINCTION  Species can become extinct: Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world. Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world. Ecologically: Occurs when so few members of a species are left they no longer play its ecological role. Ecologically: Occurs when so few members of a species are left they no longer play its ecological role. Globally (biologically): Species is no longer found on the earth. Globally (biologically): Species is no longer found on the earth.

Global Extinction  Some animals have become prematurely extinct because of human activities. Figure 11-2

Endangered and Threatened Species: Ecological Smoke Alarms  Endangered species: so few individual survivors that it could soon become extinct.  Threatened species: still abundant in its natural range but is likely to become endangered in the near future. Figure 11-3

Fig. 11-3, p. 224

 Some species have characteristics that make them vulnerable to ecological and biological extinction. SPECIES EXTINCTION Figure 11-4

SPECIES EXTINCTION  Scientists use measurements and models to estimate extinction rates. The International Union for the Conservation of Nature and Natural Resources (IUCN) publishes an annual Red List, listing the world’s threatened species. The International Union for the Conservation of Nature and Natural Resources (IUCN) publishes an annual Red List, listing the world’s threatened species.Red ListRed List The 2013 Red List contains approximately 20,000 species at risk for extinction. The 2013 Red List contains approximately 20,000 species at risk for extinction. Figure 11-5

SPECIES EXTINCTION  Percentage of various species types threatened with premature extinction from human activities. Figure 11-5

IMPORTANCE OF WILD SPECIES  We should not cause the premature extinction of species because of the economic and ecological services they provide.  Some believe that each wild species has an inherent right to exist. Some people distinguish between the survival rights among various types of species (plants vs. animals). Some people distinguish between the survival rights among various types of species (plants vs. animals).

HABITAT LOSS, DEGRADATION, AND FRAGMENTATION  Conservation biologists summarize the most important causes of premature extinction as “HIPPO”: Habitat destruction, degradation, and fragmentation Habitat destruction, degradation, and fragmentation Invasive species Invasive species Population growth Population growth Pollution Pollution Overconsumption Overconsumption

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: A Disturbing Message from the Birds  The majority of the world’s bird species are found in South America. Threatened with habitat loss and invasive species. Threatened with habitat loss and invasive species. Figure 11-10

INVASIVE SPECIES  Many nonnative species provide us with food, medicine, and other benefits but a a few can wipe out native species, disrupt ecosystems, and cause large economic losses. Kudzu vine was introduced in the southeastern U.S. to control erosion. It has taken over native species habitats. Figure 11-A

INVASIVE SPECIES  Prevention is the best way to reduce threats from invasive species, because once they arrive it is almost impossible to slow their spread. Figure 11-13

OVEREXPLOITATION OVERCONSUMPTION  Some protected species are killed for their valuable parts or are sold live to collectors.  Killing predators and pests that bother us or cause economic losses threatens some species with premature extinction.  Legal and illegal trade in wildlife species used as pets or for decorative purposes threatens some species with extinction.  Myanmar Animal Trade Myanmar Animal TradeMyanmar Animal Trade

OVEREXPLOITATION OVERCONSUMPTION  Rhinoceros are often killed for their horns and sold illegally on the black market for decorative and medicinal purposes. Figure 11-16

Case Study: Rising Demand for Bushmeat in Africa  Bushmeat hunting has caused the local extinction of many animals in West Africa.  Can spread disease such as HIV/AIDS and ebola virus. Figure 11-17

PROTECTING WILD SPECIES: LEGAL AND ECONOMIC APPROACHES  International treaties have helped reduce the international trade of endangered and threatened species, but enforcement is difficult. One of the most powerful is the 1975 Convention on International Trade of Endangered Species (CITES). One of the most powerful is the 1975 Convention on International Trade of Endangered Species (CITES). Signed by 169 countries, lists 900 species that cannot be commercially traded.Signed by 169 countries, lists 900 species that cannot be commercially traded.

Case Study: The U.S. Endangered Species Act  One of the world’s most far-reaching and controversial environmental laws is the 1973 U.S. Endangered Species Act (ESA). ESA forbids federal agencies (besides defense department) to carry out / fund projects that would jeopardize an endangered species. ESA forbids federal agencies (besides defense department) to carry out / fund projects that would jeopardize an endangered species. ESA makes it illegal for Americans to engage in commerce associated with or hunt / kill / collect endangered or threatened species. ESA makes it illegal for Americans to engage in commerce associated with or hunt / kill / collect endangered or threatened species.

Case Study: The U.S. Endangered Species Act  Biodiversity hotspots in relation to the largest concentrations of rare and potentially endangered species in the U.S. Figure 11-18

Endangered Species  Because of scarcity of inspectors, probably no more than 1/10 th of the illegal wildlife trade in the U.S. is discovered. Figure 11-19

Endangered Species  Congress has amended the ESA to help landowners protect species on their land.  Some believe that the ESA should be weakened or repealed while others believe it should be strengthened and modified to focus on protecting ecosystems.  Many scientists believe that we should focus on protecting and sustaining biodiversity and ecosystem function as the best way to protect species.

How Would You Vote? To conduct an instant in-class survey using a classroom response system, access “JoinIn Clicker Content” from the PowerLecture main menu for Living in the Environment.  Should the Endangered Species Act be modified to protect and sustain the nation's overall biodiversity? a. No. Protecting entire habitats will only further interfere with the rights of landowners. a. No. Protecting entire habitats will only further interfere with the rights of landowners. b. Yes. Protecting endangered habitats is more efficient and effective than saving individual species. b. Yes. Protecting endangered habitats is more efficient and effective than saving individual species.

PROTECTING WILD SPECIES: THE SANCTUARY APPROACH  Gene banks, botanical gardens and using farms to raise threatened species can help prevent extinction, but these options lack funding and storage space.  Zoos and aquariums can help protect endangered animal species by preserving some individuals with the long-term goal of reintroduction, but suffer from lack of space and money.

RECONCILIATION ECOLOGY  Reconciliation ecology involves finding ways to share places we dominate with other species. Replacing monoculture grasses with native species. Replacing monoculture grasses with native species. Maintaining habitats for insect eating bats can keep down unwanted insects. Maintaining habitats for insect eating bats can keep down unwanted insects. Reduction and elimination of pesticides to protect non-target organisms (such as vital insect pollinators). Reduction and elimination of pesticides to protect non-target organisms (such as vital insect pollinators).