C HAPTER 11 Sustaining Biodiversity: The Species Approach

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. Marsh Deer, Blue Whale, Lake Sturgeon Ecologically : Occurs when so few members of a species are left they no longer play its ecological role. Sea otter, California Spiny Lobster Globally (biologically) : Species is no longer found on the earth.

G LOBAL E XTINCTION Some animals have become prematurely extinct because of human activities. Figure 11-2

E NDANGERED AND T HREATENED S PECIES 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

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

E STIMATING EXTINCTION RATES 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. Red List The 2004 Red List contains 15,589 species at risk for extinction. 1 out of every 4 mammal species 1 out of every 7 plant species 1 out of every 8 bird speices Figure 11-5

Estimating extinction rates is difficult because Extinction takes a long time on a human time scale and documentation is limited Many species are not identified We know little about the species we have identified

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

IMPORTANCE OF WILD SPECIES Ecological services Control pests, store carbon, recycle nutrients Economic services Food, fuel, timber, paper, medicines Genetic information Recreational pleasure Ecotourism Biophilia= affinity for nature

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

HABITAT LOSS, DEGRADATION, AND FRAGMENTATION The greatest threat to a species is the loss, degradation, and fragmentation of where it lives. Figure 11-7

HABITAT LOSS, DEGRADATION, AND FRAGMENTATION Reduction in ranges of four wildlife species, mostly due to habitat loss and overharvest. Figure 11-8

W HICH SPECIES ARE MOST VULNERABLE ? Specialist K strategist- low reproductive rate Contain desirable characteristics video

C ASE S TUDY : A D ISTURBING M ESSAGE FROM THE B IRDS Human activities are causing serious declines in the populations of many bird species due to deforestation, introduction of nonnative species, nets in oceans, power lines, and buildings. Figure 11-9

INVASIVE SPECIES Many nonnative species provide us with food, medicine, and other benefits (like reduced soil erosion=kudzu) 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 Many invasive species have been introduced intentionally. Figure 11-11

INVASIVE SPECIES Many invasive species have been introduced unintentionally. Figure 11-11

INVASIVE SPECIES The Argentina fire ant was introduced to Mobile, Alabama in 1932 from South America. Most probably from ships. No natural predators. Zebra Mussels in the Great Lakes Figure 11-12

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

Fig , 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 of Successful 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 of Ecosystems Vulnerable to Invader Species

POPULATION GROWTH, POLLUTION, AND CLIMATE CHANGE Population growth, affluenza, and pollution have promoted the premature extinction of some species. Projected climate change threatens a number of species with premature extinction. Polar bears

P OLLUTION Each year pesticides: Kill about 1/5 th of the U.S. honeybee colonies. 67 million birds million fish. Threaten 1/5 th of the U.S.’s endangered and threatened species. Example of biomagnification of DDT in an aquatic food chain. Figure 11-15

OVEREXPLOITATION Some protected species are killed for their valuable parts or are sold live to collectors. Legal and illegal trade in wildlife species used as pets or for decorative purposes threatens some species with extinction. Burmese python

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

C ASE S TUDY : R ISING D EMAND FOR B USHMEAT IN A FRICA 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 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). Signed by 169 countries, lists 900 species that cannot be commercially traded.

T HE U.S. E NDANGERED S PECIES A CT 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 makes it illegal for Americans to engage in commerce associated with or hunt / kill / collect endangered or threatened species.

O THER ACTS / TREATIES TO PROTECT SPECIES National Marine Fisheries Service- id and protect threatened or endangered marine species US Fish and Wildlife Service- id and protect threatened or endangered terrestrial species

PROTECTING WILD SPECIES 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. 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).

Fig , p. 246 Do not buy furs, ivory products, and other materials made from endangered or threatened animal species. Do not buy wood and paper products produced by cutting remaining old- growth forests in the tropics. Do not buy birds, snakes, turtles, tropical fish, and other animals that are taken from the wild. Do not buy orchids, cacti, and other plants that are taken from the wild. Spread the word. Talk to your friends and relatives about this problem and what they can do about it. What Can You Do? Protecting Species