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Transcript
Chapter 22 Sustaining Wild Species The Story of Martha Oh high above the trees and the reeds like rainbows they landed soft as moonglow in greens and reds they fluttered past the windows ah but nobody cared or saw til the hungry came in crowds with their guns and dozers and soon the peace was over God what were they thinking of? Oh on and on til dreams come true you know a piece of us all goes with you Oh the birds went down they fell and they faded to the dozens Til in a Cincinnati Zoo was the last one Yes all that remained was the last with a name of Martha Very proud, very sad, but very wise Oh as the lines filed by there were few who cared or could be bothered how could anyone have treated you harder and it was all for a dollar or more Oh on and on til dreams come true you know a piece of us all goes with you Oh and surrounded there by some of whom wept around her in a corner of the cage they found her she went as soft as she came so shy til the last song oh the passenger pigeon was gone... John Harold The last word in ignorance is the person who says of an animal or plant: “What good is it?...If the land mechanism as a whole is good, whether we understand it or not…Harmony with land is like harmony with a friend; you cannot cherish his right hand and chop off his left. Aldo Leopold Key Concepts Human effects on biodiversity Importance of biodiversity How human activities affect wildlife Management of wildlife 22.1 Human Impacts on Biodiversity A. Factors that increase biodiversity Physically diverse habitat Small - moderate environmental disturbances Evolution B. Factors that decrease biodiversity Environmental stress- *decrease habitats is greatest threat Large disturbances Extreme conditions Limitation of essential resources Introduction of alien species Geographic Isolation 1% Probably extinct 7% Critically imperiled 67% Secure or apparently secure 8% Imperiled 16% Vulnerable 1% Other Fig. 22.4, p. 554 How Serious is a Loss of Biodiversity? 1. 2. 3. Some argue that the threat is exaggerated… We don’t know how many species there are We don’t know the true value of all species in ecosystems Estimates are based on models that lack data Should We Focus on Sustaining Species or Ecosystems? A. Ecosystem Approach Major goal is to assure that there is enough protected land and water to provide habitat. B. Species-by-Species Approach Identify most at-risk species Understand the species Focus on protecting them C. SANCTUARY APPROACH - Creation of Refuges - Gene Banks/Botanical Gardens - Zoo/Aquariums * Egg Pulling * Captive Breeding The Species Approach Goal Protect species from premature extinction Strategies • Identify endangered species • Protect their critical habitats Tactics • Legally protect endangered species • Manage habitat • Propagate endangered species in captivity • Reintroduce species into suitable habitats The Ecosystem Approach Goal Protect populations of species in their natural habitats Strategy Preserve sufficient areas of habitats in different biomes and aquatic systems Tactics • Protect habitat areas through private purchase or government action • Eliminate or reduce populations of alien species from protected areas • Manage protected areas to sustain native species • Restore degraded ecosystems 22.2 Three Types of Extinction A. Local Extinction: Species is no longer found in an area it once was, but it is found in other areas. Ex. White tail deer was near a local extinction but has recovered to a large population size. *Roosevelt was most influential in increasing the White Tailed Deer population. B. Ecological Extinction: So few that it can no longer play its ecological role C. Biological Extinction: Species is no longer found anywhere on the earth Biological Extinction is Forever Irreversible loss of genes What are Endangered and Threatened Species? Endangered: So few individual survivors that the species can become extinct over all or part of its range Threatened or Vulnerable: Still abundant in its natural range and may become endangered Threatened and Endangered Species of Pennsylvania Links: PA GAME COMMISSION PA FISH AND BOAT COMMISSION US FISH AN WILDLIFE SERVICE Rare Species: Naturally small populations due to limited geographic range Locally depleted by human activities Vulnerable to extinction Characteristic Low reproductive rate (K-strategist) Specialized niche Narrow distribution Feeds at high trophic level Fixed migratory patterns Rare Commercially valuable Large territories Examples Blue whale, giant panda, rhinoceros Blue whale, giant panda, Everglades kite Many island species, elephant seal, desert pupfish Bengal tiger, bald eagle, grizzly bear Blue whale, whooping crane, sea turtles Many island species, African violet, some orchids Snow leopard, tiger, elephant, rhinoceros, rare plants and birds California condor, grizzly bear, Florida panther Background vs. Mass Extinction Background Extinction- A small, naturally occurring, low rate extinction. Fossil records show 1-14 species a year (Approximately 1 species / million) 0.0001% per year B. Mass ExtinctionA rise above the background rate, often catastrophic and global. Estimated to be five in the past 500 million years Geological Periods Number of families of marine animals Carboniferous Cretaceous Devonian Jurassic Silurian Triassic Tertiary Ordovician Permian Quaternary Cambrian 800 Mass extinctions 600 ? 400 200 0 570 505 438 360 408 286 208 245 Millions of years ago 144 65 0 2 Fig. 22.10, p. 558 Extinction of the Dinosaurs 22.3 Why Care About Biodiversity? The Earth’s Overall Biodiversity has 2 Types of Value: 1. 2. Instrumental Value: Usefulness to humans Intrinsic Value: Because they exist regardless of their value SIDE NOTE Biologists claim that species have medical and scientific value, ecological value, and economic value. Value of Nature Instrumental (human centered) Intrinsic (species or ecosystem centered) Utilitarian Goods Ecological services Non-utilitarian Existence Aesthetic Information Bequest Recreation Fig. 22.11, p. 561 Instrumental Values Utilitarian (Use) -Economic goods -Ecological Services -Information -Recreation Non-Utilitarian (Nonuse) -Existence -Aesthetic -Bequest Rauvolfia Rauvolfia sepentina, Southeast Asia Tranquilizer, high blood pressure medication Fig. 22.12a, p. 561 Foxglove Digitalis purpurea, Europe Digitalis for heart failure Fig. 22.12b, p. 561 Pacific yew Taxus brevifolia, Pacific Northwest Ovarian cancer Fig. 22.12c, p. 561 Cinchona Cinchonaledogeriana, South America Quinine for malaria treatment Fig. 22.12d, p. 561 Rosy periwinkle Cathranthus roseus, Madagascar Hodgkin's disease, lymphocytic leukemia Fig. 22.12e, p. 561 Neem tree Azadirachta indica, India Treatment of many Diseases acts as an insecticide Fig. 22.12f, p. 561 Habitat loss Causes of Premature Extinction Overfishing Habitat degradation Basic Causes Climate change • Population growth • Rising resource use • No environmental accounting • Poverty Introducing nonnative species Commercial hunting and poaching Pollution Predator and pest control Sale of exotic pets and decorative plants Fig. 22.13, p. 564 22.4 CAUSES FOR PREMATURE EXTINCTION A. Habitat loss and degradation -Greatest threat to wild species -In U.S. the major disturbances are… *agriculture *development *outdoor recreation *grazing *pollution Habitat Fragmentation –A large, continuous area of habitat is reduced in area and divided into a patchwork of isolated areas. Can result in loss of genetic diversity, create barriers, create limited habitats. Former range Range today (34,000–54,000 left) Asian or Indian Elephant Fig. 22.14d, p. 565 Range 100 years ago Range today (about 2,300 left) Fig. 22.14a, p. 565 Indian Tiger Range in 1700 Range today (about 2,400 left) * endangered* Black Rhino Fig. 22.14b, p. 565 Decline due to habitat loss, legal ivory trade, and poaching Probable range 1600 Range today (600,000 left) African Elephant 2. Harm by Nonnative Species -U.S. has 50,000 Nonnative species -49% of 1,200 endangered and threatened species are threatened by nonnative species. **Can decrease biodiversity. -Nonnative species catagories… fall into two A. Deliberately Introduced B. Accidentally Introduced A. Deliberately Introduced -Supply 98% of U.S. food -Can have detrimental affects w/no predators, parasites, or competition to control numbers. Example: Asian Carp KUDZU VINE: B. Accidentally Introduced Many times they are transported in shipping products Expansion of the fire ant in southern states. 1918 2000 Fig. 22.18, p. 570 Tiger Mosquitointroduced the West Nile disease Formosia termite -Control of Nonnative species begins with identifying characteristics that allow them to succeed Characteristics of Successful Invader Species • High reproductive rate, short generation time (rselected species) • Pioneer species • Long lived Characteristics of Ecosystems Vulnerable to Invader Species • Similar climate to habitat of invader • Absence of predators on invading species • Early successional species • High dispersal rate • Release growthinhibiting chemicals into soil • Generalists • High genetic variability • Low diversity of native species • Absence of fire • Disturbed by human activities 3. Commercial Hunting/Poaching -International trade of wild plant and animals is worth $10-$20 billion dollars per year. -1/4 of total is in illegal sales. Animals worth more if made an attraction for Ecotourism. Gorilla - $150,000 Chimp - $50,000 Rhino Horn - $13,000/lb. Bushmeat - $150 million /yr. Fig. 22.24, p. 576 This family of Gorillas was Slaughtered for Bush meat Orphans of the Slaughter Gorilla Hand: A Delicacy Poachers Use a Chain Saw to Remove a Rhino Horn POACHING A EGG Ivory Trade Profiting from Safaris 5min flash A Controversial Management Practice “Culling” 5min flash 4. Exotic Pets -25 Million U.S. households have exotic birds -Leads to a loss of Ecotourism -Use of Cyanide to capture tropical fish -Orchids and Cacti for decoration * The pet trade has depleted populations of birds, tropical fish, and mammals Using Chemicals to catch exotic fish 3min flash 5. Climate Change and Pollution -Increase in global warming -Introduction of pesticides/herbicides, etc. 6. Loss of Genetic Diversity -Decreased ability to reproduce and adapt to changing conditions Founder Effect Genetic Drift Inbreeding Bottleneck Effect 22.5 Solutions to Protecting Species A. International Treaties 1. CITES (1975 Convention on International Trade in Endangered Species) 800 species that can’t be traded 29,000 species regulated since they are at risk of becoming threatened LIMITED SUCCESS for CITES Difficult to enforce Small fines for those convicted Countries can exempt themselves Many countries that have not signed CITES B. National Laws 1. 2. LACEY ACT 1900: Prohibits transport of dead animals across state lines without a permit ENDANGERED SPECIES ACT: *Most species on listed on ESA have not recovered. Illegal to import or trade any product from an endangered or threatened species… Unless used for scientific purposes * 1st organism to be listed on ESA due to global climate change = Polar Bear Who Determines What is Protected? National Marine Fisheries Service: List and identify Ocean Species U.S. Fish and Wildlife Service: Identify all other endangered species. Also regulates the enforcement of the ESA and CITIES Treaty * Fines and imprisonment can be imposed to ensure the protection of endangered species 6 Hotspots for Endangered Species 2 4 3 5 Top Six Hot Spots 6 1 Hawaii 2 San Francisco Bay area 3 Southern Appalachians 4 Death Valley 5 Southern California 6 Florida Panhandle Concentration of rare species 1 Low Moderate High Fig. 22.23, p. 575 Charcoal Roadblock 4min http://www.youtube.com/watch?v=9cnPlj d_jJg&feature=player_embedded http://www.youtube.com/wat ch?v=tJ5nfgYJhD4 What Have Land Owners Done to Avoid the ESA? Some land owners have managed their land so less endangered species use it *The Bald Eagle was the first organism to be protected under the ESA Should We Weaken the ESA Concerns about the economic impacts… 1. Make protection on private land voluntary 2. Have the gov’t pay for lost land 3. Make it harder to list new species 4. Give the secretary of the interior the right to allow a species to become extinct 5. Can allow exemptions to states 6. Prohibit public lawsuits Should the ESA be Strengthened? 0.05% of projects have been blocked by ESA The act does allow for economic concerns “God Squad” – any federal project can be exempted from ESA to prevent economic loss Government will bargain with HCP’s Habitat Conservation Plans (HCP) Used as a compromise between the interests of land owners and the threatened species Owners are allowed to destroy some habitat or endangered species on private land… In exchange for taking measures to protect the species Protective Measures of HCP’s Set aside a part of the habitat as a preserve Pay to relocate to a suitable habitat Pay the government to buy suitable habitat elsewhere. What are the concerns with this type of plan? Removing Barriers of Protection Safe Harbor Agreement: Land owners voluntarily restore habitat on their land Candidate Conservation Agreement: Landowners volunteer to take steps to help declining populations not yet listed Should We Try to Protect all Species? Can’t possibly save all Focus on… 1. Most likely to succeed 2. Ones with the greatest amount of ecological value 3. The most useful in medicine * FOCUS ON KEYSTONE SPECIES Biome % of Area Disturbed Temperate broadleaf forests 94% Temperate evergreen forests 94% Temperate grasslands 72% Mixed mountain systems 71% Tropical dry forests 70% Subtropical and temperate rain forests 67% Cold deserts and semidesert 55% Mixed island systems 53% Warm deserts and semideserts 44% Tropical humid forests 37% Tropical grasslands 26% Temperate Boreal forests 18% Fig. 22.15, p. 566 Tundra 0.7% Type of Nonnative Organism Crop disease Annual Losses and damages $23.5 billion Crop weeds $23.5 billion Rats $19 billion Feral cats and outdoor pet cats $17 billion Crop insects Livestock diseases Forest insects and diseases $14 billion $9 billion $4.8 billion Zebra mussels $3 billion Common pigeon $1.1 billion Formosan termite $1.1 billion Fishes $1.1 billion Asian clam $1.1 billion Feral pigs $0.8 billion Starlings $0.8 billion Fire ant $0.6 billion Fig. 22.16, p. 566 Estimation of Extinction Risks 1. 2. 3. Population Viability Analysis (PVA) Risk assessment with math and stats Minimal Viable Population (MVP) Smallest # of individuals necessary to ensure the survival of a population Minimum Dynamic Area (MDA) Minimum area of habitat needed to maintain the MVP