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CHAPTER 6. Wild Species and Biodiversity. An introduction to wildlife and biodiversity. Puffins are seabirds that live in cold coastal waters In Maine, hunting and predatory gulls almost wiped them out, despite protective laws Project Puffin brought birds from Newfoundland in the 1970s
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CHAPTER 6 Wild Species and Biodiversity
An introduction to wildlife and biodiversity Puffins are seabirds that live in cold coastal waters In Maine, hunting and predatory gulls almost wiped them out, despite protective laws Project Puffin brought birds from Newfoundland in the 1970s Chicks were installed on Eastern Egg Rock island Gulls were removed Painted decoys and tapes of puffin calls attracted birds The island now has 101 pairs of puffins Terns, petrels, and albatrosses have also been reintroduced
The value of wild species and biodiversity Ecosystem capital: all goods and services provided to humans by natural systems In 2008, capital loss from the world’s financial crisis = $1–1.5 trillion Capital loss from ecosystem degradation = $2–4.5 trillion The basis of ecosystem capital = ecosystems The basis of ecosystems = wild species To maintain ecosystem sustainability, you must save ecosystem integrity, resilience, processes, biodiversity
The value of wildlife Instrumental value: a species’ or organism’s existence or use benefits some other entity Food, shelter, source of income Usually anthropocentric: beneficiaries are humans We preserve species to enjoy the benefits they provide Intrinsic value: something has value for its own sake It does not have to be useful to us Do animals have rights? Or are they simply property? Many people believe only humans have intrinsic value There is no reason to preserve “insignificant” species
Species have value as sources for materials Most food comes from agriculture Wild populations have traits for competitiveness, resistance to parasites, tolerance to adverse conditions Agricultural populations have lost these traits A cultivar (cultivated variety): a highly selected strain of the original species Has minimal genetic variation Produces outstanding yields in specific conditions Can not adapt to other conditions
New food plants Potential for developing new cultivars is lost if wild populations are destroyed Out of the hundreds of thousands of plants species Humans use only 7,000 species Three species (wheat, maize, rice) provide 50% of global food demands Modern plants can not produce under many environmental conditions 30,000 plant species could be cultivated For example, every part of the winged bean is edible
Wood and other raw materials Animal husbandry, forestry, and aquaculture also select species from nature Three billion people use wood for heating and cooking Demand for wood is increasing Scientists are predicting a “timber famine” or “fuelwood crisis” Rubber, oils, nuts, fruits, spices, and gums also come from forests All are valuable for humans
Banking genes Genetic bank: living things are a bank of the gene pools of all living species Wild relatives of cultivated crops are being preserved England’s Millennium Seed Bank has 1 billion seeds Norway’s Svalbard Global Seed Vault holds seeds as a backup for other seed banks Zoos act as genetic banks for animals The United Kingdom’s Frozen Ark Project collects cells and DNA from species likely to go extinct Genetic diversity is preserved while we try to slow extinction
Species have value as sources for medicine Madagascar’s rosy periwinkle has revolutionized treatment of childhood leukemia and Hodgkin’s disease The Chinese star anise’s fruit is used in Tamiflu Paclitaxel from the Pacific yew tree treats ovarian, breast, and small-cell cancers Ethnobotany: studies relationships between plants and people 3,000 plants have anticancer properties The search for beneficial drugs has helped create parks Bioprospecting: studies indigenous people’s use of plants
Values support commercial interests Recreational and aesthetic values support commercial interests In 2006, 87.5 million U.S. adults participated in wildlife-centered recreation (e.g., bird-watching, hunting) Generated 2.6 million jobs and $108 million Ecotourism: tourists visit a place to observe wild species or unique ecological sites It is the largest foreign exchange-generating enterprise for many developing countries Environmental degradation affects commercial interests
Scientific value We learn basic laws of nature The way ecosystems and the world work Biota provides the nature we study But most scientific work is done to gain medicines, agricultural benefits, and other outcomes
A cautionary note Using wild species and biodiversity causes problems Little money from the rosy periwinkle’s success went back to Madagascar, a very poor country Large companies have patented ancient herbal remedies But indigenous people may not benefit Ecotourism may bring money to poor countries It increases pollution, harms wildlife, changes cultures Whale-watching boats disrupt whale feeding Tourist boats frighten flamingoes and reduce their feeding
The loss of instrumental value Biodiversity loss has tremendous negative effect on the world The Economics of Ecosystems and Biodiversity’s (TEEB) 2008 report detailed the economic and life-quality effects of biodiversity loss Loss of biodiversity and ecosystem services = $78 billion/yr Highest for the world’s poorest Such an outcome is morally wrong
Species have value for their own sake The usefulness (instrumental value) of species is obvious But it’s not enough to protect many species Some species have no obvious value Another strategy: emphasize the intrinsic value of species Extinction is an irretrievable loss of something valuable The existence of a species means it has a right to exist Living things have ends and interests of their own “Destroying species is like tearing pages out of an unread book” Humans have a responsibility to the natural world
Religious support for intrinsic value Jewish and Christian traditions show God’s concern for wild species God declared his creation was good and blessed it All wild things have intrinsic value and deserve care The Islamic Quran (Koran) says the environment is Allah’s creation and should be protected Native American religions have a strong environmental ethic Hindu philosophy has strong grassroots environmentalism Religions represent a potentially powerful force for preserving biodiversity
Biodiversity and its decline Biodiversity includes genetic diversity in species as well as the diversity of species, communities, and ecosystems Two measures calculate biodiversity The number of species How “even” the species are A habitat has low biodiversity if it is dominated by one species with few members of other species Diversity is higher if dominance of any one species is low
How many species? Most people are unaware of the great diversity of species Groups that are rich in species: flowering plants and insects Conspicuous or commercially important groups are more explored and described Birds, mammals, fish, trees Fully exploring biodiversity would require a major effort Estimates continue to rise as rain forests are explored
Most threatened species are in the tropics The tropics have almost unimaginable biodiversity 43 species of ants occur on one tree in Peru Equal to all ant fauna of the British Isles 300 species of trees on a 1-ha (2.5-acre) plot 1,000 species of beetles on one tree species in Panama Tropical forests are also experiencing the highest rate of deforestation The species inventory is so incomplete it’s almost impossible to assess extinction rates
Reasons for the decline Past extinctions were caused by climate change, plate tectonics and asteroid impacts Current threats to biodiversity are described by HIPPO Habitat destruction Invasive species Pollution Population Overexploitation
Biodiversity loss in the developing world Future losses in biodiversity will be greatest in the developing world Biodiversity is greatest So is human population growth Asia and Africa have lost two-thirds of their original natural habitat People’s desire for a better life Desperate poverty Global market for timber and other resources
Habitat change: conversion The greatest source of biodiversity loss (36%) Conversion, fragmentation, simplification, intrusion Species are adapted to specific habitats When the habitat changes, the species goes with it Conversion of natural areas to farms, housing, malls, marinas, industrial centers Forest cover has been reduced by 40% North American songbird declines are due to loss of winter habitat and fragmentation of summer habitat Croplands that replace grasslands support few species
Habitat change: fragmentation Natural landscapes have large patches of habitat connected to other similar patches Human-dominated landscapes consist of a mosaic of different land uses The patches contrast with neighboring patches Fragments of habitat support small numbers and populations of species Species become vulnerable to extinction Species that require large areas, grow slowly, or have unstable populations are also vulnerable
Fragmentation: edge Reducing habitat size increases edge Exposing species to predators and nest parasites Edge is beneficial to some species but not to others Kirtland’s warbler, an endangered species, depends on jack pines in Michigan Forests have been fragmented, creating edge Brown-headed cowbirds are nest parasites that lay their eggs in the warbler’s nest Edge also favors nest predators (crows, magpies, jays)
Habitat change: simplification and intrusion Simplification: humans simplify habitats Removing logs and trees changes forest microhabitats Streams are channelized (straightened), reducing fish and invertebrate species Intrusion: human structures Millions of migrating birds crash into telecommunication towers Cell phone tower lights affect birds migrating at night Up to a billion birds die each year by crashing into windows
Invasive species An exotic (alien) species: one that is introduced into an area from somewhere else Most don’t survive or don’t become pests Invasive species: thrives, spreads, and can eliminate native species by predation or competition Accidental introductions: the brown tree snake Entered Guam on cargo ships Within 50 years, it eliminated 9 of 12 bird species It has no natural enemies Wildlife officials are trying to prevent its spread
May I introduce… Species have been deliberately introduced Kudzu: to reclaim eroded or degraded lands Saltcedar in the American southwest to control erosion Horticultural desirables: the Brazilian pepper in Florida has fundamentally changed the Everglades Aquaculture: the farming of shellfish, seaweed, and fish Introducing parasites, seaweeds, invertebrates, pathogens Species escape and enter nearby waterways
Over time Humans have transplanted species throughout history European colonists brought weeds and plants to America Field, lawn, and roadside plants are exotics Animals have been introduced to North America House mouse, Norway rat, wild boar, starling, horse The house cat is one of the most destructive exotics Kills 1 billion small mammals and hundreds of millions of birds Species transplanted from North America cause problems Gray squirrels outcompete red squirrels in Europe
Invasive species and trophic levels Nonnative plants have different resistance mechanisms Make it harder for herbivores to eat Energy and materials may not pass up the food chain Norway maples were introduced to North America in 1756 They provide less food up the food chain for herbivores (caterpillars) and their predators (song birds)
Pollution kills or reduces populations Agricultural nitrogen and phosphorus enter the Mississippi River, creating a 10,000 square mile “dead zone” in the Gulf of Mexico It destroys or alters habitats Oil spills kill seabirds and sea mammals Pesticides (DDT) travel up the food chain and become more concentrated in higher consumers Sediments kill species in lakes, rivers, and bays Climate change is already impacting species
Pollution can spread disease Pathogen pollution: human wastes can spread pathogenic microorganisms to wild species Manatees have been killed by human papillomavirus, cryptosporidium, and microsporidium Deformities in amphibians result from the larval stage of a flatworm invading tadpoles High nutrient pollution led to large snail populations Snails are intermediate hosts of the flatworm
Population Human populations put pressure on species Direct use, habitat conversion, pollution Large numbers of humans use resources wild species need Even if each person uses small amounts of resources A small group of people can overuse resources People with highly consumptive resources have a disproportionate effect on the environment Different levels of consumption and numbers of people drive tensions between countries
Overexploitation: trade in exotics Overexploitation: overharvest of a particular species Removing individuals faster than they can reproduce Overuse of species harms ecosystems Driven by greed, ignorance, desperation, poor management Overcutting forests, overgrazing, overhunting, etc. Trade in exotics: much trade is illegal Illegal trade generates $12 billion/yr, the third largest source after drugs and guns Consumers pay huge prices for “luxuries” (e.g., polar bear rugs)
Illegal wildlife trade Some parrots sell for $10,000 A panda skin rug sells for $25,000 Shahtoosh shawls come from wool of the Tibetan antelope (chiru) A “must-have” luxury item for the wealthy It takes three dead antelopes to make one shawl 20,000 chiru were killed/year and their numbers plummeted Retraining Kashmiri weavers and providing them with other wools and public court cases made them less popular
Overexploitation: greed The prospect of extinction does not stop exploiters Huge profits drive poaching and the black market trade Exotic pets (fish, reptiles, birds) are taken from the wild Most do not survive the transition Do not buy wild-caught species The U.S. 1992 Wild Bird Conservation Act Stops wild capture of declining birds, upholds treaties, and supports sustainable breeding programs In 2007, the European Union (EU) prohibited importing wild birds
Consequences of losing biodiversity Biodiversity is essential for ecosystem goods and services Mangroves and coral reefs buffer against storms Ecotourism depends on biodiversity Energy flow and nutrient cycling are driven by species Keystone species: species whose role is vital to survival of other species Predators control herbivores Umbrella species: larger animals that need unspoiled habitat (wolves, elephants, tigers, moose, etc.)
K-strategists are at most risk Many declining species are K-strategists Long-living, large, older at first reproduction, high parental care Vulnerable to rapid environmental change Can decline even if they are common R-strategists are less likely to be harmed by humans Widely distributed, small, rapid reproduction, low parental care, ability to migrate Likely to become pest species
Moving forward What if humans cause a species to go extinct? The natural world is less beautiful or interesting There are glimmers of hope Species thought to be extinct aren’t New populations of rare species are discovered New protections emerge from a change in policy The EU’s concern over avian flu limits bird imports Scientific accomplishments and captive breeding Led to the first live rhinoceros birth from frozen semen
Saving wild species: conservation biology Scientists are at the front lines of protecting biodiversity They know what is out there and what is declining Stopping biodiversity losses requires laws and enforcement People need to look at the big picture Conservation biology: focuses on protection of populations and species Uses captive breeding, telemetry, and tracking devices Taxonomy: the cataloging and naming of species Understanding species and identifying those in trouble A lack of experts makes it hard to find solutions
