Sustaining Biodiversity: The Species Approach Chapter 9
Core Case Study: The Passenger Pigeon: Gone Forever Passenger pigeon hunted to extinction by 1900 Commercial hunters used a "stool pigeon” Archeological record shows five mass extinctions Human activities: hastening more extinctions?
Passenger Pigeon
9-1 What Role Do Humans Play in the Premature Extinction of Species? Concept 9-1A We are degrading and destroying biodiversity in many parts of the world, and these threats are increasing. Concept 9-1B Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on the earth (the background rate), and by the end of this century, the extinction rate is expected to be 10,000 times the background rate.
Human Activities Are Destroying and Degrading Biodiversity Human activity has disturbed at least half of the earth’s land surface Fills in wetlands Converts grasslands and forests to crop fields and urban areas Degraded aquatic biodiversity
Extinctions Are Natural but Sometimes They Increase Sharply Background extinction Extinction rate Mass extinction: causes? Levels of species extinction Local extinction Ecological extinction Biological extinction
Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (1) Premature extinctions due to Habitat destruction Overhunting
Conservative estimates of extinction = % Growth of human population will increase this loss Rates are higher where there are more endangered species Tropical forests and coral reefs, wetlands and estuaries—sites of new species—being destroyed Speciation crisis Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (2)
Animal Species Prematurely Extinct Due to Human Activities
Fig. 9-2, p. 185 Passenger pigeon Great aukDodoGolden toadAepyornis (Madagascar)
Effects of a 0.1% Extinction Rate
Fig. 9-3, p. 186 Number of species existing Effects of a 0.1% extinction rate 5 million5,000 extinct per year 14 million 14,000 extinct per year 50 million 50,000 extinct per year 100 million 100,000 extinct per year Number of years until one million species are extinct
Endangered and Threatened Species Are Ecological Smoke Alarms Endangered species Threatened species, vulnerable species Characteristics of such species
Endangered Natural Capital: Species Threatened with Premature Extinction
Fig. 9-4, p. 187 Grizzly bear Kirkland’s warbler Knowlton cactus Florida manatee African elephant Utah prairie dog Swallowtail butterfly Humpback chub Golden lion tamarin Siberian tiger Giant panda Black-footed ferret Whooping crane Northern spotted owl Blue whale Mountain gorilla Florida panther California condor Hawksbill sea turtle Black rhinoceros
Characteristics of Species That Are Prone to Ecological and Biological Extinction
Fig. 9-5, p. 188 Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros Specialized niche Blue whale, giant panda, Everglades kite Narrow distribution Elephant seal, desert pupfish Feeds at high trophic level Bengal tiger, bald eagle, grizzly bear Fixed migratory patterns Blue whale, whooping crane, sea turtle Rare African violet, some orchids Commercially valuable Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Large territories California condor, grizzly bear, Florida panther CharacteristicExamples
Fig. 9-5, p. 188 Stepped Art Fixed migratory patterns Blue whale, whooping crane, sea turtle Feeds at high trophic level Bengal tiger, bald eagle, grizzly bear Narrow distribution Elephant seal, desert pupfish Commercially valuable Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros CharacteristicExamples Rare African violet, some orchids Large territories California condor, grizzly bear, Florida panther Specialized niche Blue whale, giant panda, Everglades kite
Percentage of Various Species Threatened with Premature Extinction
Fig. 9-6, p. 189 Fishes 34% (51% of freshwater species) Amphibians 32% Mammals 25% Reptiles 20% Plants 14% Birds 12%
Science Focus: Estimating Extinction Rates Is Not Easy Three problems Hard to document due to length of time Only 1.8 million species identified Little known about nature and ecological roles of species identified Document little changes in DNA Use species–area relationship Mathematical models
9-2 Why Should We Care about Preventing Premature Species Extinction? Concept 9-2 We should prevent the premature extinction of wild species because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness to us.
Species Are a Vital Part of the Earth’s Natural Capital Instrumental value Use value Ecotourism: wildlife tourism Genetic information Nonuse value Existence value Aesthetic value Bequest value Ecological value
Natural Capital Degradation: Endangered Orangutans in a Tropical Forest
Natural Capital: Nature’s Pharmacy
Fig. 9-8, p. 190 Pacific yew Taxus brevifolia, Pacific Northwest Ovarian cancer Rosy periwinkle Cathranthus roseus, Madagascar Hodgkin's disease, lymphocytic leukemia Rauvolfia Rauvolfia sepentina, Southeast Asia Anxiety, high blood pressure Neem tree Azadirachta indica, India Treatment of many diseases, insecticide, spermicide Foxglove Digitalis purpurea, Europe Digitalis for heart failure Cinchona Cinchona ledogeriana, South America Quinine for malaria treatment
Endangered Scarlet Macaw is a Source of Beauty and Pleasure
Science Focus: Using DNA to Reduce Illegal Killing of Elephants for Their Ivory 1989 international treaty against poaching elephants Poaching on the rise Track area of poaching through DNA analysis of elephants Elephants damaging areas of South Africa: Should they be culled?
Are We Ethically Obligated to Prevent Premature Extinction? Intrinsic value: existence value Edward O. Wilson: biophilia phenomenon Biophobia
Science Focus: Why Should We Care about Bats? Vulnerable to extinction Slow to reproduce Human destruction of habitats Important ecological roles Feed on crop-damaging nocturnal insects Pollen-eaters Fruit-eaters Unwarranted fears of bats
ABC Video: Bachelor pad at the zoo
ABC Video: Hsing Hsing dies
ABC Video: Penguin rescue
9-3 How do Humans Accelerate Species Extinction? Concept 9-3 The greatest threats to any species are (in order) loss or degradation of its habitat, harmful invasive species, human population growth, pollution, climate change, and overexploitation.
Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO Habitat destruction, degradation, and fragmentation Invasive (nonnative) species Population and resource use growth Pollution Climate change Overexploitation
Causes of Depletion and Premature Extinction of World Species
Fig. 9-10, p. 193 NATURAL CAPITAL DEGRADATION Underlying Causes Population growth Rising resource use Undervaluing natural capital Poverty Direct Causes Habitat loss Pollution Commercial hunting and poaching Habitat degradation and fragmentation Climate change Sale of exotic pets and decorative plants Introduction of nonnative species Overfishing Predator and pest control Causes of Depletion and Premature Extinction of Wild Species
Natural Capital Degradation: Reduction in the Ranges of Four Wildlife Species
Fig. 9-11a, p. 194
Indian Tiger Range 100 years ago Range today
Fig. 9-11b, p. 194
Black Rhino Range in 1700 Range today
Fig. 9-11c, p. 194
African Elephant Probable range 1600 Range today
Fig. 9-11d, p. 194
Asian or Indian Elephant Former range Range today
Fig. 9-11, p. 194 Stepped Art Indian Tiger Range 100 years ago Range today Black Rhino Range in 1700 Range today African Elephant Probable range 1600 Range today Asian or Indian Elephant Former range Range today
Science Focus: Studying the Effects of Forest Fragmentation on Old-Growth Trees Tropical Biologist Bill Laurance, et al. How large must a forest fragment be in order to prevent the loss of rare trees?
Case Study: A Disturbing Message from the Birds (1) Habitat loss and fragmentation of the birds’ breeding habitats Forests cleared for farms, lumber plantations, roads, and development Intentional or accidental introduction of nonnative species Eat the birds
Case Study: A Disturbing Message from the Birds (2) Seabirds caught and drown in fishing equipment Migrating birds fly into power lines, communication towers, and skyscrapers Other threats Oil spills Pesticides Herbicides Ingestion of toxic lead shotgun pellets
Case Study: A Disturbing Message from the Birds (3) Greatest new threat: Climate change Environmental indicators Economic and ecological services
Distribution of Bird Species in North America and Latin America
Fig. 9-12, p. 195 Number of bird species
The Ten Most Threatened Song Birds in the United States
Fig. 9-13, p. 196 Cerulean warblerSprague’s pipitBichnell’s thrush Black-capped vireo Golden-cheeked warbler Florida scrub jayCalifornia gnatcatcher Kirtland's warblerHenslow's sparrow Bachman's warbler
Science Focus: Vultures, Wild Dogs, and Rabies: Unexpected Scientific Connections Vultures poisoned from diclofenac in cow carcasses More wild dogs eating the cow carcasses More rabies spreading to people
Some Deliberately Introduced Species Can Disrupt Ecosystems Most species introductions are beneficial Food Shelter Medicine Aesthetic enjoyment Nonnative species may have no natural Predators Competitors Parasites Pathogens
Some Harmful Nonnative Species in the United States
Fig. 9-14a, p. 199
Deliberately Introduced Species Purple loosestrife European starling African honeybee (“Killer bee”) NutriaSalt cedar (Tamarisk) Marine toad (Giant toad) Water hyacinthJapanese beetle Hydrilla European wild boar (Feral pig)
Fig. 9-14b, p. 199
Accidentally Introduced Species Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Eurasian ruffe Common pigeon (Rock dove) Formosan termite Zebra mussel Asian long- horned beetle Asian tiger mosquito Gypsy moth larvae
Fig. 9-14, p. 199 Stepped Art Deliberately introduced species Purple loosestrife European starling African honeybee (“Killer bee”) NutriaSalt cedar (Tamarisk) Marine toad (Giant toad) Water hyacinth Japanese beetle Hydrilla European wild boar (Feral pig) Accidentally introduced species Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Eurasian ruffe Common pigeon (Rock dove) Formosan termite Zebra mussel Asian long- horned beetle Asian tiger mosquito Gypsy moth larvae
Case Study: The Kudzu Vine Imported from Japan in the 1930s “ The vine that ate the South” Could there be benefits of kudzu?
Kudzu Taking Over an Abandoned House in Mississippi, U.S.
Some Accidentally Introduced Species Can Also Disrupt Ecosystems Argentina fire ant: 1930s Pesticide spraying in 1950s and 1960s worsened conditions Burmese python
Argentina Fire Ant Accidentally Introduced into Mobile, Alabama, U.S.
Prevention Is the Best Way to Reduce Threats from Invasive Species Prevent them from becoming established Learn the characteristics of the species Set up research programs Try to find natural ways to control them
Characteristics of Invader Species and Ecosystems Vulnerable to Invading Species
What Can You Do? Controlling Invasive Species
Other Causes of Species Extinction (1) Population growth Overconsumption Pollution Climate change
Other Causes of Species Extinction (2) Pesticides DDT: Banned in the U.S. in 1972 Bioaccumulation Biomagnification
Bioaccumulation and Biomagnification
Fig. 9-19, p. 202 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 DDT in water ppm, or 3 ppt
Fig. 9-19, p. 202 Stepped Art DDT in water ppm, or 3 ppt DDT in small fish (minnows) 0.5 ppm DDT in zooplankton 0.04 ppm DDT in fish-eating birds (ospreys) 25 ppm DDT in large fish (needle fish) 2 ppm
Case Study: Where Have All the Honeybees Gone? Honeybees responsible for 80% of insect- pollinated plants Dying due to? Pesticides Parasites Bee colony collapse syndrome
Case Study: Polar Bears and Global Warming Environmental impact on polar bears Less summer sea ice PCBs and DDT 2007: Threatened species list
Polar Bear with Seal Prey
Illegal Killing, Capturing, and Selling of Wild Species Threatens Biodiversity Poaching and smuggling of animals and plants Animal parts Pets Plants for landscaping and enjoyment Prevention: research and education
White Rhinoceros Killed by a Poacher
Individuals Matter: Jane Goodall Primatologist and anthropologist 45 years understanding and protecting chimpanzees Chimps have tool-making skills
Rising Demand for Bush Meat Threatens Some African Species Indigenous people sustained by bush meat More hunters leading to local extinction of some wild animals
Bush Meat: Lowland Gorilla
Animation: Humans affect biodiversity
Active Figure: Habitat loss and fragmentation
Video: Bird species and birdsongs
9-4 How Can We Protect Wild Species from Premature Extinction? (1) Concept 9-4A We can use existing environmental laws and treaties and work to enact new laws designed to prevent species extinction and protect overall biodiversity. Concept 9-4B We can help to prevent species extinction by creating and maintaining wildlife refuges, gene banks, botanical gardens, zoos, and aquariums.
9-4 How Can We Protect Wild Species from Premature Extinction? (2) Concept 9-4C According to the precautionary principle, we should take measures to prevent or reduce harm to the environment and to human health, even if some of the cause-and- effect relationships have not been fully established, scientifically.
International Treaties Help to Protect Species 1975: Convention on International Trade in Endangered Species (CITES) Signed by 172 countries Convention on Biological Diversity (BCD) Focuses on ecosystems Ratified by 190 countries (not the U.S.)
Case Study: The U.S. Endangered Species Act (1) Endangered Species Act (ESA): 1973 and later amended in 1982, 1983, and 1985 Identify and protect endangered species in the U.S. and abroad Hot Spots Habitat Conservation Plan (HCP) colony
Case Study: The U.S. Endangered Species Act (2) Mixed reviews of the ESA Weaken it Repeal it Modify it Strengthen it Simplify it Streamline it
Confiscated Products Made from Endangered Species
Science Focus: Accomplishments of the Endangered Species Act (1) Species listed only when serious danger of extinction Takes decades for most species to become endangered or extinct More than half of the species listed are stable or improving Budget has been small
Science Focus: Accomplishments of the Endangered Species Act (2) Suggested changes to ESA Increase the budget Develop recovery plans more quickly Establish a core of the endangered organism’s survival habitat
We Can Establish Wildlife Refuges and Other Protected Areas 1903: Theodore Roosevelt Wildlife refuges Most are wetland sanctuaries More needed for endangered plants Could abandoned military lands be used for wildlife habitats?
Gene Banks, Botanical Gardens, and Wildlife Farms Can Help Protect Species Gene or seed banks Preserve genetic material of endangered plants Botanical gardens and arboreta Living plants Farms to raise organisms for commercial sale
Zoos and Aquariums Can Protect Some Species (1) Techniques for preserving endangered terrestrial species Egg pulling Captive breeding Artificial insemination Embryo transfer Use of incubators Cross-fostering
Zoos and Aquariums Can Protect Some Species (2) Limited space and funds Critics say these facilities are prisons for the organisms
What Can You Do? Protecting Species
Case Study: Trying to Save the California Condor Largest North American bird Nearly extinct Birds captured and breed in captivity By 2007, 135 released into the wild Threatened by lead poisoning
The Precautionary Principle Species: primary components of biodiversity Preservation of species Preservation of ecosystems