Chapter 12 Biodiversity: The Species Approach

What are the three types of species extinction?

The three levels of species extinction are local, ecological, and biological.1. Local extinction occurs when a species disappears from an area in which it once

inhabited, but is found elsewhere in the world.2. Ecological extinction occurs when the number of members of a particular species

is so low that they cannot fulfill their ecological roles in their biological communities.

3. Biological extinction occurs when a species has disappeared from the earth.

How do we classify Organisms headed for extinction?How do we classify Organisms headed for extinction?

EndangeredEndangered species are so few in number that the species could soon become extinct over species are so few in number that the species could soon become extinct over all or part of its natural range.all or part of its natural range.

Threatened/vulnerableThreatened/vulnerable species are still abundant in their natural range but, because of loss species are still abundant in their natural range but, because of loss in numbers, is likely to become endangered in the near future. in numbers, is likely to become endangered in the near future.

(E.O. Wilson states) “The first species to go tend to be the big, slow, and tasty and whose (E.O. Wilson states) “The first species to go tend to be the big, slow, and tasty and whose valuable parts can be sold.”valuable parts can be sold.”

The The passenger pigeonpassenger pigeon represents lost natural capital, primarily because of overhunting and represents lost natural capital, primarily because of overhunting and habitat destruction directly attributable to man. habitat destruction directly attributable to man.

A survey in 2000 (Natural Conservancy) found that about one-third of 21,000 animal A survey in 2000 (Natural Conservancy) found that about one-third of 21,000 animal and plant species in the U.S. are vulnerable to premature extinction.and plant species in the U.S. are vulnerable to premature extinction.

Determining Extinction

Estimates of the current rate of species extinction are based on information about habitat destruction and species-area relationship, use of models such as:

(1) population viability analysis (PVA), estimates of (2) minimum viable population (MVP), estimates of (3) minimum dynamic area (MDA), and differing assumptions about the earth's total number of species, their distribution, and the rates of tropical deforestation.

Characteristics of species that are prone to extinctionCharacteristics of species that are prone to extinction

• Low reproductive rate (K-strategist)-Low reproductive rate (K-strategist)- Blue whale, giant panda, rhinoceros Blue whale, giant panda, rhinoceros• Specialized niche–Specialized niche– Blue whale, giant panda, Everglades kite Blue whale, giant panda, Everglades kite• Narrow distributionNarrow distribution – many island species, elephant seal, desert pupfish – many island species, elephant seal, desert pupfish• Feeds at a high trophic level-Feeds at a high trophic level- Bengal tiger, bald eagle, grizzly bear Bengal tiger, bald eagle, grizzly bear• Fixed migratory patterns-Fixed migratory patterns- Blue whales, whooping cranes, sea turtles Blue whales, whooping cranes, sea turtles• RareRare- Many island species, African violet, some orchids- Many island species, African violet, some orchids• Commercially valuable-Commercially valuable- Snow leopard, tiger, elephant, rhinoceros, rare plants Snow leopard, tiger, elephant, rhinoceros, rare plants

and birdsand birds• Large territories-Large territories- California condors, grizzly bears, Florida panthers California condors, grizzly bears, Florida panthers

What is the impact of human activities on extinction?

• Currently, the rate of extinction is estimated to be 1,000–10,000 times the Currently, the rate of extinction is estimated to be 1,000–10,000 times the rate before mankind existed.rate before mankind existed.

• Using estimated extinction rates, 20% of the world’s present plant and Using estimated extinction rates, 20% of the world’s present plant and animal species will be gone by 2030; 50% would vanish by 2099.animal species will be gone by 2030; 50% would vanish by 2099.

Factors influencing greater extinction ratesFactors influencing greater extinction rates• Species loss and biodiversity loss will likely increase because of exponential Species loss and biodiversity loss will likely increase because of exponential

population growth.population growth.

• Biologically diverse areas’ (hot spots) rate of extinction may be as high as 25–Biologically diverse areas’ (hot spots) rate of extinction may be as high as 25–50%. The extinction rate in these “hot spots” deserves special attention.50%. The extinction rate in these “hot spots” deserves special attention.

• Possible colonization sites for new species are being eliminated, degraded, Possible colonization sites for new species are being eliminated, degraded, and simplified by human activities so that new species cannot arise. By and simplified by human activities so that new species cannot arise. By reducing this rate of speciation, we are creating a speciation crisis. reducing this rate of speciation, we are creating a speciation crisis.

Solution? - A precautionary strategy to prevent a significant decrease in the Solution? - A precautionary strategy to prevent a significant decrease in the genetic, species, ecological, and functional diversity of the earth is necessary.genetic, species, ecological, and functional diversity of the earth is necessary.

Why should we preserve wild species?

• Wild species have value—economic and ecological—which are important to Wild species have value—economic and ecological—which are important to the earth.the earth.

• We are destroying species biodiversity more quickly than new species can We are destroying species biodiversity more quickly than new species can evolve. evolve. It will take 5 million years for speciation to rebuild the animals and It will take 5 million years for speciation to rebuild the animals and plants we will destroy in 100 years. We should preserve species for their plants we will destroy in 100 years. We should preserve species for their instrumental value.instrumental value.

• Instrumental value-Instrumental value- usefulness of a species to us in the form of economic or usefulness of a species to us in the form of economic or ecological servicesecological services

Examples: Mountain Gorillas

Thailand Species Trade

Sharks

What are some of the economic and ecological benefits?

• Medicinal propertiesMedicinal properties are found in many plants and some animals. are found in many plants and some animals.• Genetic informationGenetic information in species helps them adapt and produce new species. This in species helps them adapt and produce new species. This

information can be used to develop food and medicines for people. Wild species information can be used to develop food and medicines for people. Wild species provide a bank of genetic information.provide a bank of genetic information.

• Recreational valueRecreational value is provided by plants and animals. is provided by plants and animals.• Eco-tourism generatesEco-tourism generates money to help poor countries; preserving plants and money to help poor countries; preserving plants and

animals is much more economically wise than destroying them.animals is much more economically wise than destroying them.– A male lion skin is worth $1,000; a male lion living for 7 years produces A male lion skin is worth $1,000; a male lion living for 7 years produces

$515,000 in tourist dollars.$515,000 in tourist dollars.

– Bats, often targeted for destruction by man, feed on crop-damaging insects, Bats, often targeted for destruction by man, feed on crop-damaging insects, pollinate flowers, as well as distribute plants by excreting undigested seeds. pollinate flowers, as well as distribute plants by excreting undigested seeds. Bats are keystone species in the tropics.Bats are keystone species in the tropics.

Some of the economic and ecological benefits of present species have not even been Some of the economic and ecological benefits of present species have not even been identified; we are destroying our chance for a a future.identified; we are destroying our chance for a a future.

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Secondary factors leading to premature extinction

HIPPO – Habitat destructions and fragmentation, Invasive (alien) species, Population growth, Pollution and Overharvesting

Habitat destruction and fragmentation

Species are more vulnerable to extinction when their habitats are divided and in to smaller more isolated patches

Invasive SpeciesInvasive Species

Solution:Solution:

Prevention is the best way to reduce the threats from nonnative species because Prevention is the best way to reduce the threats from nonnative species because once they have arrived it is difficult and expensive to slow their spread.once they have arrived it is difficult and expensive to slow their spread.

• Deliberate or accidental Deliberate or accidental introduction of nonnative introduction of nonnative species can trigger species can trigger ecological disruptions that ecological disruptions that lead to premature lead to premature extinction of native extinction of native species. Once a nonnative species. Once a nonnative species gets established in species gets established in an ecosystem, its an ecosystem, its wholesale removal is wholesale removal is virtually impossible. The virtually impossible. The best strategy is to prevent best strategy is to prevent nonnative species from nonnative species from being introduced and being introduced and becoming established.becoming established.

Invasive SpeciesInvasive Species

Figure 12-11 Natural capital degradation:expansion of the Argentina fire ant in southern states,1918-2000. This invader is also found in Puerto Rico, New Mexico, and California, (Data from U.S. Department of Agriculture)

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Figure 12-10 Kudzu taking over a house and a truck. This vine can grow 5 centimeters (2 inches) per hour and is now found from east Texas to Florida and as far north as southeastern Pennsylvania and Illinois. Kudzu was deliberately introduced into the United States for erosion control, but it cannot be stopped by being dug up or burned. Grazing by goats and repeated doses of herbicides can destroy it, but goats and herbicides also destroy other plants, and herbicides can contaminate water supplies. Recently, scientists have found a common fungus (Myrotheciurn verrucaria) that can kill kudzu within a few hours, apparently without harming other plants.

Kudzu

Fire Ants

Impact of Population Growth

Deer populations have exploded in the suburbs due to invasion of their habitats Deer populations have exploded in the suburbs due to invasion of their habitats by humans.by humans.

1.1. Deer are edge species; they live in the woods and feed in more open Deer are edge species; they live in the woods and feed in more open areas.areas.

2.2. Deer kill more people in the U.S. than any other wild species due to Deer kill more people in the U.S. than any other wild species due to collisions between deer and vehicles.collisions between deer and vehicles.

3.3. No easy answers are available for reducing the deer population; each No easy answers are available for reducing the deer population; each proposed remedy is generally expensive and time consuming.proposed remedy is generally expensive and time consuming.

4.4. Researchers are experimenting with various possible methods of birth Researchers are experimenting with various possible methods of birth control to decrease the population.control to decrease the population.

Poaching and Hunting

At least one-fourth of the international At least one-fourth of the international trade in wild plants and animals trade in wild plants and animals involves the illegal sale of endangered involves the illegal sale of endangered or threatened species or their parts. or threatened species or their parts. Most demand for illegal wildlife comes Most demand for illegal wildlife comes from wealthy consumers, but illegal from wealthy consumers, but illegal hunting for bushmeat as a source of hunting for bushmeat as a source of protein for local people and for protein for local people and for restaurants in many parts of the world restaurants in many parts of the world is a growing problem.is a growing problem.

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Planet in Peril Video Clip

To poachers, a To poachers, a live live mountain gorillamountain gorilla is worth $150,000, a is worth $150,000, a pandapanda pelt pelt $100,000 (only $100,000 (only about 1,500 pandas are left in the wild), a about 1,500 pandas are left in the wild), a chimpanzeechimpanzee $50,000, and an $50,000, and an Imperial Imperial Amazon macawAmazon macaw $30,000. A $30,000. A rhinocerosrhinoceros horn horn is worth as much as $28,600 per is worth as much as $28,600 per kilogram ($13,000 per pound) because of its use in dagger handles in the Middle kilogram ($13,000 per pound) because of its use in dagger handles in the Middle East and as a fever reducer and alleged aphrodisiac in China—the world's largest East and as a fever reducer and alleged aphrodisiac in China—the world's largest consumer of wildlife—and other parts of Asia.consumer of wildlife—and other parts of Asia.

Protecting Wild Species- Legal ApproachProtecting Wild Species- Legal Approach• The 1975 The 1975 CConvention on onvention on IInternational nternational TTrade in rade in EEndangered ndangered SSpecies pecies

(CITES)(CITES) has helped to reduce international trade in many threatened has helped to reduce international trade in many threatened animals. The animals. The CConvention on onvention on BBiological iological DDiversity (CBD)iversity (CBD) binds signatory binds signatory governments to reversing the decline in biodiversity, but it has not been governments to reversing the decline in biodiversity, but it has not been ratified by the United States and some other key governments.ratified by the United States and some other key governments.

• In the United States, In the United States, The Lacey Act of 1900The Lacey Act of 1900 prohibits the transport of live or prohibits the transport of live or dead animals or their parts across state lines without a permit. The dead animals or their parts across state lines without a permit. The Endangered Species Act of 1973 (ESA)Endangered Species Act of 1973 (ESA) prohibits the import or trading of prohibits the import or trading of products made from an endangered or threatened species.products made from an endangered or threatened species.

ESA ControversyESA Controversy

There is controversy over whether the government should compensate There is controversy over whether the government should compensate private property owners who suffer financial losses when it restricts how private property owners who suffer financial losses when it restricts how they can use their land because of the presence of threatened or they can use their land because of the presence of threatened or endangered species.endangered species.

Congress has amended the Endangered Species Act to help landowners Congress has amended the Endangered Species Act to help landowners protect endangered species on their land. protect endangered species on their land. Safe-harbor agreementsSafe-harbor agreements and and voluntary candidate conservation agreementsvoluntary candidate conservation agreements

Examples of successful recovery plans include those for the American alligator, the Examples of successful recovery plans include those for the American alligator, the gray wolf, the bald eagle, and the peregrine falcon. gray wolf, the bald eagle, and the peregrine falcon. Bad newsBad news. . About half of current About half of current recovery plans exist only on paper, mostly because of political opposition and recovery plans exist only on paper, mostly because of political opposition and limited funds.limited funds.

U.S. Biological hot spots and recovery plansU.S. Biological hot spots and recovery plans

Protecting Wild Species: The Sanctuary Approach The sanctuary approach is being used to protect wild species.The sanctuary approach is being used to protect wild species.

• 542 federal refuges protect wildlife, but the habitats are deteriorating due to 542 federal refuges protect wildlife, but the habitats are deteriorating due to invasive species, pollutants, and little operational or maintenance funding.invasive species, pollutants, and little operational or maintenance funding.

• About one-fifth of U.S. endangered and threatened species have habitats in the About one-fifth of U.S. endangered and threatened species have habitats in the refuge system.refuge system.

• Human overuse by hunters, fishermen, and off-road vehicle traffic has hurt the Human overuse by hunters, fishermen, and off-road vehicle traffic has hurt the refuges.refuges.

• Gene banks, botanical gardens, and farms can be used to raise threatened species Gene banks, botanical gardens, and farms can be used to raise threatened species and help protect species from extinction, but funding is inadequate.and help protect species from extinction, but funding is inadequate.

• Raising some threatened or endangered species on farms can take some of the Raising some threatened or endangered species on farms can take some of the pressure off them and perhaps offer some for commercial sale.pressure off them and perhaps offer some for commercial sale.

• Zoos and aquariums can help protect some endangered animal species as well, Zoos and aquariums can help protect some endangered animal species as well, but they are both notoriously underfunded. but they are both notoriously underfunded.

• More than three-fourths of the refuges are concentrated along major bird migration More than three-fourths of the refuges are concentrated along major bird migration corridors.corridors.

Major Migratory Flyways

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Reconciliation Ecology

• Reconciliation Ecology – the science of inventing, establishing and maintaining new habitats to conserve species diversity in place where people live, work or play.

• Michael L. Rosenzweig (Win-Win Ecology: How Earth’s Species Can Survive in the Midst of Human Enterprise) identifies the real challenge for biodiversity: to sustain wild species in the human-dominated portion of nature.

• Rosenzweig advocates that we implement reconciliation ecology: learn to share the spaces we dominate with other species. It is the science of inventing, establishing, and maintaining new habitats to conserve species diversity where people live out their lives.

Reconciliation Ecology

There are several ways to implement reconciliation ecology.1. Maintain diverse yards using native plants, which attract

certain species.2. Share responsibility for supporting bio-diverse yards and

gardens.3. Apply reconciliation ecology to local plant and animal life (for

example, bluebirds project).4. Planting rooftop gardens can support a variety of species,

provide insulation, reduce evapotranspiration, conserve water, and cool cities.

5. Golden Gate Park in San Francisco is a good example of reconciliation ecology; it was transformed from sand dunes to park by humans.

6. Government land, college campuses, and schools could be used for reconciliation ecology laboratories.