Sustaining Biodiversity: The Species Approach

Sustaining Biodiversity: The Species Approach1Core Case Study: The Passenger Pigeon: Gone ForeverPassenger pigeon hunted to extinction by 1900

Commercial hunters used a "stool pigeon

Geological record shows five mass extinctions

Human activities: hastening more extinctions?

2Figure 9.1Lost natural capital: passenger pigeons have been extinct in the wild since 1900 because of human activities. The last known passenger pigeon died in the U.S. state of Ohios Cincinnati Zoo in 1914.

3What Role Do Humans Play in the Premature Extinction of Species?We are degrading and destroying biodiversity in many parts of the world, and these threats are increasing.

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.4

The extinction of the Passenger Pigeon had two major causes: commercial exploitation of pigeon meat on a massive scale[25]and loss of habitat.[77] Human Activities Are Destroying and Degrading BiodiversityHuman activity has disturbed at least half of the earths land surfaceFills in wetlandsConverts grasslands and forests to crop fields and urban areas

Degraded aquatic biodiversity6Extinctions Are Natural but Sometimes They Increase SharplyBackground extinction- The ongoing extinction of individual species due to environmental or ecological factors such as climate change, disease, loss of habitat, or competitive disadvantage in relation to other species. Background extinction occurs at a fairly steady rate over geological time and is the result of normal evolutionary processes, with only a limited number of species in an ecosystem being affected at any one time.

Background extinction rate, also known as normal extinction rate, refers to the standard rate ofextinctionin earths geological and biological history before humans became a primary contributor to extinctions. This is primarily the pre-human extinction rates during periods in between majorextinction events.

7Mass extinction: causesPoorly understood, but involve global changes in environmental conditions.

Levels of species extinctionLocal extinction, or extirpation- Local extinction, orextirpation, is the condition of aspecies(or othertaxon) which ceases to exist in the chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions.Ecological extinction-is defined as the reduction of a species to such low abundance that, although it is still present in the community, it no longer interacts significantly with other species.[1]Ecological extinction stands out because it is the interaction ecology

Biological extinction- extinctionis the end of anorganismor of a group of organisms (taxon), normally aspecies.

Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (2)Habitat destructionOver-hunting (extirpation, poaching, etc) Pollution of water, land, and air (global warming appears to be causing harm to some species, especially amphibians).Habitat fragmentation (isolating tiny populations, preventing animals from finding mates).

9Animal Species Prematurely Extinct Due to Human Activities

10Endangered and Threatened Species Are Ecological Smoke AlarmsEndangered species so few individual survivors that could be soon become extinct.International Union for the Conservation of Nature (IUCN), or the World Conservation Union.Since 1960, published Red ListIn 2007, listed 16, 306 animals and plants that are in danger of extinction60% higher than in 1995.

Threatened species - threatened speciesare any species which are vulnerable toendangermentin the near future.

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Grizzly bearKirklands warblerKnowlton cactusFlorida manateeAfrican elephantUtah prairie dogSwallowtail butterflyHumpback chubGolden lion tamarinSiberian tigerGiant pandaBlack-footed ferretWhooping craneNorthern spotted owlBlue whaleMountain gorillaFlorida pantherCalifornia condorHawksbill sea turtleBlack rhinocerosFigure 9.4Endangered natural capital. Some species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the worlds species and roughly 1,300 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger.Fixed migratory patternsBlue whale, whooping crane, sea turtle

Feeds at high trophic levelBengal tiger, bald eagle, grizzly bear

Narrow distributionElephant seal, desert pupfish

Commercially valuableSnow leopard, tiger, elephant, rhinoceros, rare plants and birds

Low reproductive rate (K-strategist)Blue whale, giant panda, rhinocerosCharacteristicExamples

RareAfrican violet, some orchids

Large territoriesCalifornia condor, grizzly bear, Florida panther

Specialized nicheBlue whale, giant panda, Everglades kite

Figure 9.5Characteristics of species that are prone to ecological and biological extinction.

Figure 9.6Endangered natural capital: percentage of various types of species threatened with premature extinction because of human activities (Concept 9-1A

14Science Focus: Estimating Extinction Rates Is Not EasyThree problemsHard to document due to length of timeOnly 1.8 million species identifiedLittle known about nature and ecological roles of species identified

Document little changes in DNASuggests species survive for 1 to 10 million years before going extinct.

Use speciesarea relationshipOn average, 90% loss of habitat results in a 50% loss of species living in that habitat.

Mathematical models

159-2 Why Should We Care about Preventing Premature Species Extinction?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.

It will take 5-10 million years for natural speciation to rebuild the biodiversity we are likely to destroy during your lifetime.16Figure 9.7Natural capital degradation: endangered orangutans in a tropical forest. In 1900, there were over 315,000 wild orangutans. Now there are less than 20,000 and they are disappearing at a rate of over 2,000 per year because of illegal smuggling and clearing of their forest habitat in Indonesia and Malaysia to make way for oil palm plantations. An illegally smuggled orangutan typically sells for a street price of $10,000. According to 2007 study by the World Wildlife Fund (WWF), projected climate change will further devastate remaining orangutan populations in Indonesia and Malaysia. Question: How would you go about trying to set a price on the ecological value of an orangutan?17Figure 9.8Natural capital: natures pharmacy. Parts of these and a number of other plant and animal species (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the worlds 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.

18Figure 9.9Many species of wildlife, such as this endangered scarlet macaw in Brazils Amazon rain forest, are a source of beauty and pleasure. These and other colorful species of parrots can become endangered when they are removed from the wild and sold (sometimes illegally) as pets.

19Science Focus: Using DNA to Reduce Illegal Killing of Elephants for Their Ivory1989 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? 20Are We Ethically Obligated to Prevent Premature Extinction?Intrinsic value, or existence value Species have an inherent right to exist and play their ecological roles, regardless of their usefulness to us.

Edward O. Wilson: biophilia phenomenon

Biophobia

219-3 How do Humans Accelerate Species Extinction?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. 22Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO (1)Habitat destruction, degradation, and fragmentationInvasive (nonnative) speciesPopulation and resource use growthPollutionClimate changeOverexploitation

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Figure 9.11Natural capital degradation: reductions in the ranges of four wildlife species, mostly as the result of habitat loss and hunting. What will happen to these and millions of other species when the worlds human population doubles and per capita resource consumption rises sharply in the next few decades? Question: Would you support expanding these ranges even though this would reduce the land available for people to grow food and live on? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)24Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO (2)Globally, habitat loss, greatest in temperate biomes, pace picking up in tropics.

Endemic speciesHawaii, the extinction capital of America63% of species at risk.

Habitat islands

Habitat fragmentation

The Bali Mynah is distributed and endemic to the island of Bali, where it is the island's only surviving endemic species. This rare bird was discovered in 1910 and is one of the world's most critically endangered birds. In fact, it has been hovering immediately aboveextinctionin the wild for several years.One in every eight bird species (12%) is threatened with extinction. Three-fourths live in forests.NumbersLocationReason(s)75% of birds speciesSumatras lowland forestsLumber and palm plantations, used for biofuels115 bird speciesBrazilBurning/clearing of rainforests for farms and ranches; 93% loss of Atlantic coastal rainforest; clearing of savannah-like cerrado for soybean plantations30% of bird species, 70% of grassland speciesNorth AmericaHabitat loss and fragmentation of breeding habitat; replaced by roads and other developments.28% of speciesWorldwideIntroduction of non-native bird-eating species52 of 388 parrot speciesWorldwidePet trade23 SeabirdsWorldwideBycatch from commercial fishing; pollution40% of waterbirdsWorldwideLoss of wetlandsCase 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 threatsOil spillsPesticidesHerbicidesIngestion of toxic lead shotgun pellets

27Case Study: A Disturbing Message from the Birds (3)Greatest new threat: Climate change

Environmental indicatorsLive in every climate and biomeRespond quickly to environmental changesEasy to track

Economic and ecological services

28Figure 9.12Distribution of bird species in North America and Latin America. Question: Why do you think more bird species are found in Latin America than in North America? (Data from The Nature Conservancy, Conservation International, World Wildlife Fund, and Environment Canada).

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Cerulean warblerSpragues pipitBichnells thrushBlack-capped vireoGolden-cheeked warblerFlorida scrub jayCalifornia gnatcatcherKirtland's warblerHenslow's sparrowBachman's warblerFigure 9.13The 10 most threatened species of U.S. songbirds. Most of these species are vulnerable because of habitat loss and fragmentation from human activities. An estimated 12% of the worlds known bird species may face premature extinction due mostly to human activities during this century. (Data from National Audubon Society)Science Focus: Vultures, Wild Dogs, and Rabies: Unexpected Scientific ConnectionsVultures poisoned from diclofenac in cow carcasses

More wild dogs eating the cow carcasses

More rabies spreading to people

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Figure 9.14Some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States.

Case Study: The Kudzu VineImported from Japan in the 1930s to control soil erosion.

The vine that ate the South

Could there be benefits of kudzu? 34Kudzu Taking Over an Abandoned House in Mississippi, U.S.

35Some Accidentally Introduced Species Can Also Disrupt EcosystemsArgentina fire ant: 1930sPesticide spraying in 1950s and 1960s worsened conditions Wiped out competitor ant species and made them more pesticide resistant.

Burmese python 36Figure 9.16The Argentina fire ant, introduced accidentally into Mobile, Alabama, in the 1930s from South America (green area), has spread over much of the southern United States (red area). This invader is also found in Puerto Rico, New Mexico, and California. Question: How might this accidental introduction of fire ants have been prevented? (Data from S. D. Porter, Agricultural Research Service, U.S. Department of Agriculture)

37Figure 9.17Some general characteristics of successful invader species and ecosystems vulnerable to invading species. Question: Which, if any, of the characteristics on the right-hand side could humans influence?

38Figure 9.18Individuals Matter: ways to prevent or slow the spread of harmful invasive species. Questions: Which two of these actions do you think are the most important? Why? Which of these actions do you plan to take?

39Other Causes of Species Extinction (1)Population growth

Overconsumption

Pollution

Climate change40Other Causes of Species Extinction (2)PesticidesDDT: Banned in the U.S. in 1972

Bioaccumulation

Biomagnification

41Figure 9.20Polar bear with seal prey on floating ice in Svalbard, Norway. Polar bears in the Arctic are likely to become extinct sometime during this century because global warming is melting the floating sea ice on which they hunt seals.

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Illegal Killing, Capturing, and Selling of Wild Species Threatens BiodiversityPoaching and smuggling of animals and plantsAnimal partsPetsPlants for landscaping and enjoyment

When commercially valuable species become endangered, black market prices soar.

Prevention: research and education43Figure 9.21White rhinoceros killed by a poacher for its horn in South Africa. Question: What would you say if you could talk to the poacher of this animal?

44The hyacinth macaw, Anodorhynchus hyacinthinus, may be worth $10 000 to an exotic bird collector, but worth $165 00 in tourist revenues left in the wild.

Figure 9.22Bush meat, such as this severed head of a lowland gorilla in the Congo, is consumed as a source of protein by local people in parts of West Africa and sold in the national and international marketplace. You can find bush meat on the menu in Cameroon and the Congo in West Africa as well as in Paris, London, Toronto, New York, and Washington, D.C. It is often supplied by poaching. Wealthy patrons of some restaurants regard gorilla meat as a source of status and power. Question: How, if at all, is this different from killing a cow for food?

469-4 How Can We Protect Wild Species from Premature Extinction? (1)We can use existing environmental laws and treaties and work to enact new laws designed to prevent species extinction and protect overall biodiversity.

We can help to prevent species extinction by creating and maintaining wildlife refuges, gene banks, botanical gardens, zoos, and aquariums. 479-4 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. 48Confiscated Products Made from Endangered Species

49Gene Banks, Botanical Gardens, and Wildlife Farms Can Help Protect SpeciesGene or seed banksPreserve genetic material of endangered plants

Botanical gardens and arboretaLiving plants

Farms to raise organisms for commercial sale

50Zoos and Aquariums Can Protect Some Species (1)Techniques for preserving endangered terrestrial speciesEgg pullingCaptive breedingArtificial inseminationEmbryo transferUse of incubatorsCross-fostering

51Zoos and Aquariums Can Protect Some Species (2)Limited space and funds

Critics say these facilities are prisons for the organisms52What Can You Do? Protecting Species

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