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Biodiversity •Three levels of Biodiversity •How many species are there? •What are the values of biodiversity? •What threatens biodiversity? •How do we protect biodiversity? •How do biologists estimate extinction rates? •How do humans affect extinction rates? What is Biodiversity? Three Levels: •Genetic Diversity- variety of different versions of the same genes within a species •Species Diversity- number of different kinds of organisms within a community or ecosystem •Ecological Diversity- richness and complexity of biological community (number of niches, trophic levels, ecological processes) How many Species Exist? • Nobody knows for suremillions still need to be studied • 1.7 million presently known • Estimates of actual number range from 1050 million • Most in the tropics (hot spots) Why are so many species unidentified and unstudied? • Biologists know most about large species – Smaller groups poorly studied • Biodiversity concentrated in tropics but most fieldwork concentrated in temperate regions • Biggest need is study of insects in tropical areas! What are the values of Biodiversity? Why do we care if it disappears? • Ecosystems and the species living in them have enormous economic value to humans – $33 trillion per year • This is known as Earth’s biological wealth • Wild species have many types of values besides dollar values Two Major Types of Species Value • Instrumental Value • Existence or use benefits another entity • Also called anthropocentric value • Intrinsic Value • Has value for its own sake • Does not have to be useful to have value • Arguments for intrinsic value in different religions • If all species created by God then all have value • We (humans) are in charge of God’s creation; it’s not here just for us but for him • Similar ideas found in Judaism, Islam Values of Biodiversity: Food & Agriculture •Ecologists estimate that up to 80,000 edible wild plants could be used by humans •Also may be useful as genetic material to improve domestic crops Values of Biodiversity: Drugs and Medicines •More than half of all prescriptions contain some natural ingredients •Value of these products is $30 billion per year •Indigenous people are rarely acknowledge or compensated for these products • Success stories include rosy periwinkle from Madagascar- used to make cancer drugs that treat childhood leukemia and Hodgkin’s disease • Many medicinal plants yet to be discovered Nature’s Pharmacy Nature’s Pharmacy Rauvolfia Rauvolfia sepentina, Southeast Asia Tranquilizer, high blood pressure medication Nature’s Pharmacy Foxglove Digitalis purpurea, Europe Digitalis for heart failure Nature’s Pharmacy Pacific yew Taxus brevifolia, Pacific Northwest Ovarian cancer Nature’s Pharmacy Cinchona Cinchona ledogeriana South America Quinine for malaria treatment Nature’s Pharmacy Rosy periwinkle Cathranthus roseus, Madagascar Hodgkin's disease, lymphocytic leukemia Nature’s Pharmacy Neem tree Azadirachta indica, India Treatment of many diseases, insecticide, spermicide Values of Biodiversity: Ecological Benefits •Organisms perform many services in their ecosystems: •Soil formation •Waste disposal •Air and water purification •Nutrient cycling •Pest control •Spaceship Earth- every species is a rivet…we don’t know which one will make the whole ship fall apart Values of Biodiversity: Aesthetic and Cultural Benefits •Outdoor Activities •Psychological and Emotional wellbeing •Spiritual •Economic Value • Ecotourism is a growing industry • Species can have value if they are beautiful, aweinspiring What Threatens Biodiversity? Natural Causes •99% of all species that ever existed have gone extinct •Mass extinctions have wiped out vast numbers of species many times before •Current rate of extinction is fastest it has ever been (1000-10,000x higher than natural rate) How Bad is It? • 12,259 species known by IUCN (World Conservation Organization) to be threatened with extinction • Sample of 47 common farmland and woodland birds monitored in 18 European countries show 71% decline from 19802002 • Two best-monitored groups of world’s animals are mammals and birds • Every 4th mammal (24%) and every 8th bird (12%) facing high risk of extinction • Across European continent – 42% of mammals threatened – 15% of birds threatened – 45% of butterflies, 30% of amphibians, 45% of reptiles, 52% of freshwater fish threatened Percentages of Various Types of Organisms Threatened with Extinction by Human Activities 34% (51% of freshwater species) Fish 24% Mammals 20% Reptiles Plants Birds 14% 12% Fig. 9-5, p. 188 Types of Species Extinction Local extinction Ecological extinction Biological extinction Some Prematurely Extinct Species Passenger pigeon Great auk Dodo Dusky seaside sparrow Aepyornis (Madagascar) Fig. 9-2, p. 185 Endangered and Threatened Species Endangered speciesin immediate danger of extinction over all or part of their range Threatened speciesnot in danger yet but vulnerable to becoming endangered Endangered and Threatened Species Grizzly bear (threatened) Mojave desert tortoise (threatened) Kirtland's warbler White top pitcher plant Swallowtail butterfly Humpback chub Arabian oryx (Middle East) Golden lion tamarin (Brazil) African elephant (Africa) Siberian tiger (Siberia) Endangered and Threatened Species West Virginia spring salamander Mountain gorilla (Africa) Giant panda (China) Pine barrens tree frog (male) Whooping crane Knowlton cactus Swamp pink Hawksbill sea turtle Blue whale El Segundo blue butterfly More Endangered and Threatened Species Florida manatee Devil's hole pupfish Ghost bat (Australia) Northern spotted owl (threatened) Snow leopard (Central Asia) Gray wolf Florida panther Symphonia (Madagascar) Black-footed ferret California condor Black lace cactus Black rhinoceros (Africa) Bannerman's turaco (Africa) Utah prairie dog (threatened) Oahu tree snail Characteristics of Extinction-prone Species Characteristic Examples Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros Specialized niche Blue whale, giant panda, Everglades kite Narrow distribution Many island species, elephant seal, desert pupfish Feeds at high trophic level Bengal tiger, bald eagle, grizzly bear Fixed migratory patterns Blue whale, whooping crane, sea turtles Rare Many island species, African violet, some orchids Commercially valuable Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Large territories California condor, grizzly bear, Florida panther Problems Estimating Extinction Rates Extinction not easily documented over time Many species remain unidentified Little is known about most identified species Estimating Extinction Rates Estimates from records and fossils Species-area relationship Models to estimate risks of extinction for a particular species Estimates of extinction rates can vary depending on available data and what assumptions are used Causes of Premature Extinction “HIPPO” Habitat destruction and fragmentation Invasive (alien) species Population growth (humans) Pollution Overharvesting Causes of Premature Extinction Habitat loss Overfishing Pollution Habitat degradation and fragmentation Climate change Commercial hunting and poaching Introducing nonnative species Predator and pest control Sale of exotic pets and decorative plants Secondary Causes •Population growth •Rising resource use •No environmental accounting •Poverty Basic Causes Fig. 9-7, p. 190 What Threatens Biodiversity? Habitat Destruction •Number one reason for the current increase in extinctions •Habitats most in danger include tropical and temperate forests, wetlands, and prairies Spotted Owl Reduced Ranges Indian Tiger Range 100 years ago Range today (about 2,300 left) Fig. 9-8a, p. 191 Reduced Ranges Black Rhino Range in 1700 Range today (about 2,400 left) Fig. 9-8b, p. 191 Reduced Ranges African Elephant Probable range 1600 Range today Fig. 9-8c, p. 191 Reduced Ranges Asian or Indian Elephant Former range Range today (34,000–54,000 left) Fig. 9-8d, p. 191 What Threatens Biodiversity? Habitat Fragmentation • Reduction of habitat into smaller, more scattered patches • Many species need large territories to exist • Divides population into small, vulnerable groups • Causes edge effect • Related to island biogeography What about World’s Ecosystems? • World’s forests house almost ½ global biodiversity • They are disappearing at rate of 0.8% per year • Estimated 80% of original forest that covered Earth has been cleared, damaged, or fragmented • Tropical forests vanishing at 4% per year • U.S. has lost more than 90% of its once species-rich wetlands • 1/3 of world’s coral reefs already gone, another 1/3 under threat What Threatens Biodiversity? Hunting and Fishing •Overharvesting is responsible for the depletion or extinction of many species •Examples include passenger pigeon, bison, whales •Overfishing continues to threaten many species Bison (above) and dodo (right) John James Audubon on the Passenger Pigeon: “The air was literally filled with pigeons; the light of noon-day was obscured as by an eclipse, the dung fell in spots, not unlike melting flakes of snow; and the continued buzz of wings had a tendency to lull my senses to repose…Before sunset I reached Louisville, distance from Hardensburgh 55 miles. The pigeons were still passing in undiminished numbers, and continued to do so for three days in succession.” What Threatens Biodiversity? Commercial Products and Live Specimens •Includes both live specimens (pet trade) and parts of species •Powdered rhino horn sells for $28,000 per kg Endangered Black Rhino •Other examples are tigers, elephants, tropical fish and birds, plants such as wild ginseng Confiscated Products From Endangered Species Fig. 9-18, p. 199 What Threatens Biodiversity? Predator and Pest Control / Invasive Spp. •Animals can be harmed because they are considered pests, or because they are victims of another pest control effort •Examples include prairie dogs, coyotes, bobcats •Invasive species (more than 4500 in the U.S.) include: •Zebra mussels •Purple loosestrife •Asian long-horned beetle •Kudzu •Round goby Deliberately Introduced Species Purple looselife European starling Marine toad Water hyacinth African honeybee (“Killer bee”) Japanese beetle Nutria Hydrilla Salt cedar (Tamarisk) European wild boar (Feral pig) Accidentally Introduced Species Sea lamprey (attached to lake trout) Formosan termite Argentina fire ant Zebra mussel Brown tree snake Asian long-horned beetle Eurasian muffle Common pigeon (Rock dove) Asian tiger mosquito Gypsy moth larvae Kudzu Fire Ant Invasion 1918 2000 Reducing Threats from Nonnative Species Prevention is best Identify the characteristics of nonnative species Identify vulnerable ecosystems Thoroughly inspect imports Establish appropriate international laws Discharge of ballast waters from ships What Threatens Biodiversity? Diseases •Examples include chestnut blight and distemper in black-footed ferret •When a new disease is introduced it may throw off the balance of the whole system Pollution •Often a greater threat in higher trophic levels because of bioaccumulation (marine mammals, birds of prey) •Common pollutants include pesticides and other toxic chemicals, and lead Biomagnification of DDT 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 0.000003 ppm, or 3 ppt Fig. 9-16, p. 1 Litter Kills Seals Fig. 9-19, p. 200 What Threatens Biodiversity? Genetic Assimilation •Rare species can become even more rare when they crossbreed with other species that are more numerous and more hearty. •Examples are wolves, trout, and salmon