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Sustaining Wild Species Lecture Outlines Chapter 11 Environment: The Science behind the Stories 4th Edition Withgott/Brennan This lecture will help you understand: • The scope of Earth’s biodiversity • Background extinction rates and mass extinctions • Causes of biodiversity loss • The benefits of biodiversity • Conservation biology • Conservation of species • Conservation above the species level Review: Explain the difference in genetic diversity, species richness, and ecosystem diversity. Levels of biological diversity (biodiversity) • Humans are reducing Earth’s diversity of life • Biodiversity = variety of life at all levels of organization – Species diversity – Genetic diversity – Population and community diversity Central Case: Saving the Siberian Tiger • Tigers are going extinct • The last Siberian tigers live in the Russian Far East mountains • They are hunted and poached, and their habitat was destroyed • International conservation groups are trying to save the species from extinction • Research, education, zoos, and captive breeding programs help Plate Tectonic, Earthquakes, and Volcanoes What does all this have to do with biodiversity? What is Biological Diversity? • What changes have occurred to change the biodiversity of the earth? – Background extinction – Mass extinction – Adaptive radiation • What is different today? Humans are causing this mass extinction • Humans have driven hundreds of species to extinction – Dodo bird, Carolina parakeet, passenger pigeon • Multitudes of others teeter on the brink of extinction – Whooping crane, Kirtland’s warbler, California condor The ivory-billed woodpecker may not be extinct People have hunted species to extinction Extinctions followed human arrival on islands and continents Importance of Biodiversity • Biologist estimate that for every 2,000 species that have ever lived, 1,999 of them are extinct today. • Currently species extinction is occurring at a rate of 100 to 1,000 times the natural rate of background extinction. Species diversity • Species - a set of individuals that share certain characteristics and can interbreed – Producing fertile offspring • Species diversity - the number or variety of species in a particular region – Richness = the number of species – Evenness (relative abundance) = the similarity in numbers between species • Speciation adds to species richness and Extinction reduces species richness Species diversity and evenness Compared with the boxed area at the top: Which area has greater species richness? Why? Which has reduced richness? Why? Subspecies: the level below a species • Subspecies = populations of species that occur in different areas and differ slightly from each other – Divergence stops short of separating the species – Subspecies are denoted with a third part of the scientific name Bengal tiger = Panthera tigris tigris Siberian tiger = Panthera tigris altaica Genetic diversity • Encompasses the differences in DNA among individuals • The raw material for adaptation to local conditions • Populations with higher genetic diversity can survive – They can cope with environmental change • Populations with low genetic diversity are vulnerable to environmental change or disease • Inbreeding depression = genetically similar parents mate and produce inferior offspring – Cheetahs, bison, elephant seals Ecosystem diversity • Ecosystem diversity = the number and variety of ecosystems – Including different communities and habitats in an area • May include habitats, communities, or ecosystems at the landscape level – Sizes, shapes, and connections among patches – Beaches, cliffs, coral reefs, ocean waters • An area with a variety of vegetation holds more biodiversity than the same size area with one plant type Some groups have more species than others • Species are not evenly distributed among taxonomic groups – Insects predominate over all other life-forms – 40% of insects are beetles • Groups accumulate species by: – Adapting to local conditions – Allopatric speciation – Low rates of extinction Insects outnumber all other species Measuring biodiversity is not easy • Out of the estimated 3–100 million species on Earth, 1.8 million species have been identified and described • Most widely accepted estimate of the number of species? – 14 million • It is very difficult to know how many species exist – Small organisms are easily overlooked – Many species look identical until thoroughly examined – Many remote spots on Earth remain unexplored • Entomologist Terry Erwin found 163 beetle species living on one tree species Biodiversity is unevenly distributed • Living things are not distributed evenly on Earth • Latitudinal gradient = species richness increases toward the equator Canada has 30–100 species of breeding birds, while Costa Rica has more than 600 species Latitudinal gradient has many causes… • Climate stability, high plant productivity, no glaciation – More niches, species coexistence • Diverse habitats increase species diversity and evenness – Tropical rainforests and drylands, ecotones • Human disturbance can increase habitat diversity – But only at the local level Importance of Biodiversity Economic: crop strains such as the winged bean plant (page 355), paper, fiber, dyes, lumber, oils Some potential new food sources Importance of Biodiversity Medical: drug source, testing for toxicity and drugs/vaccines • 80% of the world’s population relies on plants or plant extracts for medicines. • At least 40% of all pharmaceuticals come from the genetic resources of wild plants, mostly tropical developing countries. Example: anticancer drugs • Rosy periwinkle produces chemicals that are effective against certain cancers --- childhood leukemia (page 354) Organisms provide drugs and medicines • Wild species produce $150 billion/year of drugs • Taxol comes from the Pacific yew tree – Treats cancer • Every species that goes extinct is a lost opportunity to cure disease Species may go extinct before they can help Gastric brooding frogs went extinct in the 1980s—taking their medical secrets with them forever Importance of Biodiversity scientific knowledge: how life evolved and functions genetic engineering – the incorporation of genes from one organism into an entirely different species. *We have skills to transfer genes from one organism to another but we do not have the ability to make genes that encode for specific traits. Why destroy the genetic diversity when it may hold the solutions? Importance of Biodiversity Ecological services: nutrient cycling, pollination, soil fertility, oxygen production, climate moderation, waste recycling, detoxification, pest control, gene pool/evolution Remember Earth’s Capital???? Importance of Biodiversity Aesthetic and Recreational • Ecotourism: wildlife tourism • Americans spend 3 times more to watch wildlife than to go to movies or on professional sporting events Why Use the Precautionary Principle? Aldo Leopold said….“we have little understanding of the ecological roles of the world’s identified 1.75 million species and how to prevent the premature extinction of species as a result of our activities.” Estimates are that on average 50 - 200 species per day become extinct (above the background extinction rate) Keystone species A species that is crucial in determining the nature and structure of the entire ecosystem in which it lives; other species of a community depend on or are greatly affected by the keystone species, whose influence is much greater than would be expected by its relative abundance. These are most vulnerable to habitat loss. Why Use the Precautionary Principle? Ecosystems may lose their ability to support many forms of life because of the disappearance of local populations of key organisms Why Use the Precautionary Principle? Mathematical models indicate a time lag of several generations between habitat loss and extinction, primarily because habitat loss also removes potential colonization sites…. If this is true, biologist may be grossly underestimating the magnitude of the current biodiversity meltdown! Three Levels of Extinction Local Extinction (extirpation): when a species is no longer found in an area it once inhabited but is still found elsewhere in the world. Three Levels of Extinction Ecological Extinction: Where there are so few members of a species left that it can no longer play its ecological roles in the biological communities where it is found. Sea Otter Three Levels of Extinction Biological Extinction: Occurs when a species is no longer found anywhere on the earth. Biological extinction is FOREVER!!! Endangered vs. Threatened • What is the difference in the terms endangered and threatened? • Endangered: has so few individual survivors that the species could soon become extinct over all or most of its natural range. • Threatened: still abundant in its natural range but is declining in numbers and is likely to become endangered. Examples: grizzly bear, southern sea otter, American alligator Estimated extinction rate Current extinction rates are higher than normal • The current extinction rate is 100 to 1,000 times greater than the background rate • This rate will increase tenfold in future decades – Human population growth and resource consumption • The Red List = species facing high risks of extinction – Mammal species (21%), bird species (12%) – 17–74% of all other species • In the U.S., in the last 500 years, 237 animal and 30 plant species have been confirmed extinct – Actual numbers are undoubtedly higher Estimated Extinction Rates • Average annual extinction rate of Mammal and Bird species – 8000 B.C - A.D. 1600 1 species per 1000 – 1600 – 1900 1 species every 4 years – 1900 – 1975 1 species every year Estimated Extinction Rates • Extinction rate of All Species – 1975 – 1985 – 1990 – 2000 several hundred several thousand at least 10,000 20,000 – 50,000 Threatened Endangered Extinct Ten Characteristics of Extinction-Prone Species • • • • • found in limited areas small population size low population density large body size specialized niches and feeding habits --- Giant Panda (bamboo) • low reproductive rates Ten Characteristics of Extinction-Prone Species • fixed migrations Flyway – An established route that ducks, geese, and shorebirds follow during their annual migrations. Ten Characteristics of Extinction-Prone Species • feed at the top of long food chains or webs • have high economic value to people • need large territory : The California Condor (page 357) Snow Leopard Coat Three Root Causes of Extinction of Wildlife: • human population growth • economic systems that don’t value the environment • exploitation, degradation of wildlife habitats Human Activities Which Directly Increase the Wildlife Extinction Rate: • population growth • poverty • habitat loss Example: The dusky seaside sparrow found only in the marshes of St. Johns River in Fla. became extinct in 1987 due to human destruction of its habitat. What Type of Feedback Loop? Human Activities Which Directly Increase the Wildlife Extinction Rate: • habitat fragmentation • hunting/poaching (Carolina Parakeet, Prairie Dog) Habitat fragmentation • Habitat fragmentation = gradual, piecemeal degradation of habitat – Farming, roads, logging, etc. • Continuous habitats are broken into patches – Species needing that habitat disappear • Landscape-level strategies try to optimize areas to be preserved Habitat loss occurs in every biome • Habitat loss is responsible for declines for 83% of mammals and 85% of birds • 99% of U.S. prairies have been converted to agriculture – Grassland birds have declined 82–99% Critical population density • Animals must have minimum viable population size: below this number the species’ survival may be jeopardized because males and females have a difficult time finding each other. Problems are: – Death rate exceeds birth rate as population falls below its critical size – Remaining small population can easily be wiped out by fire, flood, disease Critical population density • Genetic diversity also decreases because the resulting smaller gene pool and inbreeding reduce population’s ability to respond to environmental changes through natural selection • An endangered species must number at least 10,000 and often more to maintain its evolutionary potential for survival. Human Activities Which Directly Increase the Wildlife Extinction Rate: • introduced species (alien species) Examples: Kudzu, Brown Tree Snake, Blue Water Hyacinth **Be familiar with examples of introduced species to the US ( Human Activities Which Directly Increase the Wildlife Extinction Rate: • uses as pets/ decorations • climate change/pollution Warming has been the greatest in the Arctic Because of melting ice, polar bears can’t hunt seals, so they were added to the endangered species list in 2008 Facts to Know • Species is considered extinct when it has not been seen for at least 50 years or when the last of a few monitored individuals die. • endemic species: Found no where else on earth • range: The area in which a particular species is found Causes and consequences of biodiversity loss Bioinformatics • Organizing and storing useful biological information about wild species using a data base • Provides computer tools to find, visualize, analyze, and communicate biological information . Biophilia An inherent affinity for the natural world (love of life) Facts to Know • Commercial extinction: Depletion of the population of a wild species used as a resource to a level at which it is no longer profitable to harvest the species. • Where is declining biological diversity the greatest problem? Florida, California, Hawaii Hawaii is #1 Biophilia E. O. Wilson popularized the notion of biophilia We have an emotional bond with other living things Facts to Know Biodiversity Hotspots: Describe relatively small areas of land that contain an exceptional number of endemic species and are at high risk from human activities. Support a great number of endemic species = species found nowhere else in the World. The area must have at least 1,500 endemic plant species (0.5% of the world total) There are 34 global biodiversity hotspots 2.3% of the planet’s land surface contains 50% of the world’s plant species and 42% of all terrestrial vertebrate species Human Causes of Species Endangerment Give an examples of: – habitat destruction, habitat fragmentation, or habitat degradation –invasive species (biological pollution) –pollution –overexploitation How Important is the Tropical Rainforest? • Cover 7% of the Earth’s surface but has as many as 50% of the Earth’s species inhabit them Tropical Deforestation and Degradation Primary causes – Rapid population growth – Poverty – Exploitive government policies – Exports to developed countries – Failure to include ecological services in evaluating forest resources Tropical Deforestation and Degradation Secondary causes – Roads – Cattle ranching – Logging – Tree plantations – Flooding from dams – Unsustainable peasant farming - Mining - Cash crops - Oil drilling What Happens When Tropical Rainforest Are Destroyed? • Birds that migrate from North America to the rain forest in Central America and the Caribbean have been declining in numbers faster than other migratory birds • The forest itself generates much of the rainfall in tropical rain forest. If half of the existing rain forest in the Amazon region of South America were to be destroyed, precipitation in the remaining forest would decrease. What Happens When Tropical Rainforest Are Destroyed? • As the land became drier, organisms adapted to moister conditions would be replace by organisms able to tolerate the drier conditions. Many endemic species would become extinct. • Disruption of the evolutionary process. – Tropical Rainforest have supplied the base of ancestral organism from which adaptive radiation occurs. – Are we eliminating nature’s ability to replace its species through adaptive radiation? Overfishing • Tragedy of the commons??? • Commercial fishing methods Bycatch • By-catch is the term used for the accidental capture of non-target species in fishing gear. Humpback whale entangled in a fishing net. By-catch Conservation Biology The scientific study of how humans impact organism and the development of ways to protect biological diversity. Conservation biology: the search for solutions • Conservation geneticists = study genetic attributes of organisms to infer the status of their populations • Minimum viable population size = how small a population can become before it runs into problems • Metapopulations = a network of subpopulations – Small populations are most vulnerable to extinction and need special attention Conservation Biology • What are the concepts that guide it? – Large habitats are more effective at safeguarding species than several habitat fragments – Large areas of habitat typically have the potential to support greater species richness. – It is better if areas of habitat for a given species are located close together rather than far apart. Conservation Biology – Areas that are inaccessible to humans are better than human accessible areas. – It is more effective and more economical to preserve intact ecosystems in which many species live than to work on preserving individual species one at a time. – Higher priority is given to preserving areas that are more biologically diverse than others. (Remember the Hot Spots?) Three Techniques of Conservation Biology 1. Ecosystem Approach • In situ conservation – Protecting habitats – Restoring damaged or destroyed habitats – Preserve balanced populations of species in their native habitat – Establish legally protected wilderness areas and wildlife reserves – Eliminate or reduce the populations of nonnative species Three Techniques of Conservation Biology 2. Species Approach • Identify endangered species and give them legal protection • Preserve and manage crucial habitats • Ex situ conservation – zoos, aquariums, botanical gardens, seed banks • Reintroducing endangered species to nature Three Techniques of Conservation Biology 3. Wildlife Management Approach • Manages game species by: – Using laws to regulate hunting – Establishing harvest quotas – Developing population management plans – Using international treaties to protect migrating game species such as waterfowl Wildlife Refuges • Teddy Roosevelt established Pelican Island off Florida’s Atlantic coast as the 1st wildlife refuge to protect the brown pelican (1903) • Now have 508 refuges, 85% are in Alaska • ¾ are wetlands for protection of migratory waterfowl Laws, Acts, and Organizations • • • • • CITES Lacey Act Endangered Species Act Wild Bird Conservation Act Magnuson Fisheries Management and Conservation Act CITES http://www.youtube.com/watch?v=C_Wpcb7G52I United States • Lacey Act (1900) – The Lacey Act prohibits the transportation of illegally captured or prohibited animals across state line. In 1900, illegal commercial hunting threatened many game species. The original Act was directed at the preservation of game and wild birds, making it a federal crime to poach game in one state with the purpose of selling it in another state. Endangered Species Act (1973) Endangered or threatened species cannot be hunted, killed, collected or injured in the United States. Endangered Species Act • Endangered Species Act (ESA) (1973) = the primary U.S. legislation for protecting biodiversity • It forbids the government and citizens from taking actions that destroy endangered species or their habitats – Or trading in products made from endangered species • The ESA’s goal is to prevent extinction – Stabilize declining populations – Enable populations to recover • In 2010, the U.S. had 1,010 species listed as endangered and 314 listed as threatened The Endangered Species Act • • • • 60% are plants and 40 % are animals. Hawaii leads this list (298+). Each year about 85 species are added to the list Requires all commercial shipments of wildlife and wildlife products enter or leave the country through one of nine designated ports. The Endangered Species Act • National Marine Fisheries Services (NMFS) identifies and list endangered and threatened ocean species. • U.S. Fish and Wildlife Service (USFWS) identifies and list all other endangered and threatened species. • Adding or removing a species from the list must be based on biology, not economic or political reasons The Endangered Species Act • Forbids federal agencies to carry out, fund, or authorize projects that would either jeopardize, destroy or modify the critical habitat. • Fines and jail sentences can be imposed on private lands to ensure protection of the habitats of endangered species. Wild Bird Conservation Act • Imposed a moratorium on importing rare bird species Magnuson Fisheries Management and Conservation Act • Gives the federal government authority to manage fisheries in the zone between 3 and 200 miles off the U.S. shore. There is no limit on the number of U.S. fishing vessels, but quotas can be imposed on the quantity of fish taken. The Convention on Biological Diversity • The Convention aims to: – Provide incentives to conserve biodiversity – Manage access to and use of genetic resources – Transfer technology (including biotechnology) – Promote scientific cooperation – Assess human effects on biodiversity – Promote biodiversity education and awareness – Provide funding for critical activities – Encourage nations to report on conservation efforts • Despite some successes, biodiversity is still being lost Protecting biodiversity: captive breeding • Captive breeding = individuals are bred and raised so they can be reintroduced into the wild – 65 plant and animal species exist only in captivity • Reintroductions can be controversial – Ranchers opposed reintroducing wolves to Yellowstone National Park – Fragmented habitat must be improved before releasing animals Biologists have raised condor chicks in captivity with the help of hand puppets that look like the heads of adult condors Protecting biodiversity: cloning • Cloning creates more individuals and saves species from extinction – DNA from an endangered species is inserted into an egg without a nucleus – The egg is inserted into a closely related species • Several mammal species have been cloned – But these efforts are not enough to recreate lost biodiversity • Without ample habitat and protection in the wild, having cloned animals in a zoo does little good Forensics protects threatened species • Forensic science (forensics) = analyzes evidence to identify or answer questions relating to a crime • Conservation scientists use forensics to protect species – Researchers use DNA to identify a species or subspecies and its geographic origin • Detecting illegal activity helps enforce laws protecting wildlife – For example, whale meat is analyzed in Asian markets – DNA from killed elephants shows many more were killed than the Zambian government admitted Umbrella species protect others • Conservation biologists use particular species as tools to conserve communities and ecosystems • Umbrella species = species that, when protected, also help protect other, less charismatic species – Often large species that need large amounts of habitat – Protecting their habitat automatically protects others • Flagship species = large and charismatic species used as spearheads for biodiversity conservation – The World Wildlife Fund’s panda bear • Some organizations are moving beyond the singlespecies approach to focus on whole landscapes Other Solutions • Biosphere Reserves • Reintroduction of endangered species Restoration ecology • Restoration ecology is the scientific study supporting the practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by human intervention and action. Restoration ecology • "Here is the means to end the great extinction spasm. The next century will, I believe, be the era of restoration in ecology" --E. O. Wilson, 1992 What Else Can We Do? • Increase Public Awareness • Support Research in Conservation Biology • Support Establishment of an International Park System • Control Pollution What Else Can We Do? • Give Economic Incentives –Fees for Medicinal Drugs –Ecotourism –Debt for Nature Swap –Payments to landowners for protecting endangered species or reduce their property tax Using innovative economic strategies • Debt-for-nature swap = a conservation organization pays off a portion of a developing country’s international debt • In exchange, the country promises to set aside reserves to: – Fund environmental education and – Better manage protected areas • The U.S.’s Tropical Forest Conservation Act – Paid $218 million in debt payments to 13 developing countries for conservation efforts • Conservation concession = conservation organizations pay nations to conserve, and not sell, resources