Ch 11 - Wikispaces 11 Biodiversity and Conservation Biology ... Bengal tiger = Panthera tigris ... Copyright © 2008 Pearson Education, Inc.,

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

PowerPoint® Slides prepared by

Jay Withgott and Heidi Marcum

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Ch 11

Biodiversity and

Conservation Biology

Part 2: Environmental Issues

and the Search for Solutions


Central Case: Saving the Siberian tiger

• The largest cat in the world

• The Russian Far East mountains house the last remaining tigers

• Nearly became extinct due to hunting, poaching and habitat destruction

• International conservation groups saved the species from extinction

- Research, education, zoos, and captive breeding programs


Biodiversity encompasses several

levels

• Humans are reducing Earth’s diversity of life

• Biodiversity – sum total of all organisms in an area

- Split into three specific levels:

- Species diversity

- Genetic diversity

- Ecosystem diversity


Species diversity

• Species Diversity = the number or variety of species in the world or in a particular region

- Richness = the number of species

- Evenness or relative abundance = extent to which numbers of individuals of different species are equal or skewed

- Speciation generates new species and adds to species richness

- Extinction reduces species richness


The taxonomy of species

• Taxonomists = scientists who classify species

- Physical appearance and genetics determines a species

- Genera = related species are grouped together

- Families = groups of genera

• Every species has a two-part scientific name: genus and species


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

Siberian tiger =

Panthera tigris

altaica

Bengal tiger =

Panthera tigris

tigris


Genetic diversity• Encompasses the differences in DNA among

individuals within species and populations

• 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

- Disease

- Inbreeding depression = genetically similar parents mate and produce inferior offspring


Ecosystem diversity

• Ecosystem diversity = the number and variety of ecosystems

• Also encompasses differing communities and habitats

• Rapid vegetation change and varying landscapes within an ecosystem promote higher levels of biodiversity


Some groups contain more species than

others

• Species are not evenly distributed among taxonomic groups

- Insects predominate over all other life-forms

- 40% of all insects are beetles

• Groups accumulate species by

- Adaptive radiation

- 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, only 1.7 - 2 million species have been successfully catalogued

• Very difficult to identify species

- Many remote spots on Earth remain unexplored

- Small organisms are easily overlooked

- Many species look identical until thoroughly examined

• Entomologist Terry Erwin found 163 beetle species specialized on one tree species


Biodiversity is unevenly distributed

• Living things are distributed unevenly across Earth

• Latitudinal gradient = species richness increases towards 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, and no glaciation

• Tropical biomes support more species and show more species evenness

- Diverse habitats increase species diversity

• Human disturbance can increase habitat diversity

- But only at the local level


Biodiversity losses and species

extinction

• Extinction = occurs when the last member of a species dies and the species ceases to exist

• Extirpation = the disappearance of a particular population from a given area, but not the entire species globally

- Can lead to extinction


Extinction is a natural process

• Paleontologists estimate 99% of all species that ever lived are now extinct

• Background rate of extinction = natural extinctions for a variety of reasons

- 1 extinction per 1 to 10 million species for mammals and marine species

- 1 species out of 1,000 mammal and marine species would go extinct every 1,000 to 10,000 years


Earth has experienced five mass

extinctions

• In the past 440 million years, mass extinctions have eliminated at least 50% of all species

• After every mass extinction the biodiversity returned to or exceeded its original state


The current mass extinction is human

caused

• During this Quaternary period, we may lose more than half of all species

- Hundreds of human-induced species extinctions, and multitudes of others, teeter on the brink of extinction

• The current global extinction rate is 100 to 1,000 times greater than the background rate

- This rate will increase tenfold in future decades due to human population growth and resource consumption


People have hunted species to extinction for

millennia

Extinctions followed human arrival on islands and continents


Current extinction rates are higher than

normal

• The Red List = an updated list of species facing high risks of extinctions

- 23% of mammal species

- 12% of bird species

- 31 - 86% of all other species

• Since 1970, 58 fish species, 9 bird species, and 1 mammal species has gone extinct

- In the U.S., in the last 500 years, 236 animal and 17 plant species are confirmed extinct

- Actual numbers are undoubtedly higher


Biodiversity loss is more than extinction

• Decreasing numbers are accompanied by smaller species’ geographic ranges

• Genetic, ecosystem, and species diversity are being lost.

• The Living Planet Index summarizes trends in populations

- Between 1970 and 2003, the Index fell by 30%


Biodiversity loss has many causes

• Reasons for biodiversity losses are multifaceted, complex, and hard to determine

- Factors may interact synergistically

• Four primary causes of population decline are:

- Habitat alteration

- Invasive species

- Pollution

- Overharvesting

• Global climate change now is the fifth cause


Habitat alteration causes biodiversity loss

• The greatest cause of biodiversity loss

- Farming simplifies communities

- Grazing modifies the grassland structure and species composition

- Clearing forests removes resources organisms need

- Hydroelectric dams turn rivers into reservoirs upstream

- Urbanization and suburban sprawl reduce natural communities

- A few species (i.e., pigeons, rats) benefit from changing habitats


Habitat alteration has occurred in every

biome

Particularly in tropical rainforests, savannas, and tropical dry forests


Invasive species cause biodiversity loss

• Introduction of non-native species to new environments

- Accidental: zebra mussels

- Deliberate: food crops

• Island species are especially vulnerable

• Invaders have no natural predators, competitors, or parasites

• Cost billions of dollars in economic damage


Pollution causes biodiversity loss

• Harms organisms in many ways

- Air pollution degrades forest ecosystems

- Water pollution adversely affects fish and amphibians

- Agricultural runoff harms terrestrial and aquatic species

- The effects of oil and chemical spills on wildlife are dramatic and well known

• The damage to wildlife and ecosystems caused by pollution can be severe

- But it tends to be less than the damage caused by habitat alteration or invasive species


Overharvesting causes biodiversity loss

• Vulnerable species are large, few in number, long-lived, and have few young (K-selected species)

- The Siberian tiger is hunted without rules and regulations

- The early 1990s saw increased poaching because of powerful economic incentives

- Many other species affected: Atlantic gray whale, sharks, gorillas

Today the oceans contain only 10% of the large animals they

once did


Climate change causes biodiversity

loss

• Emissions of greenhouse gases warms temperatures

- Modifies global weather patterns and increases the frequency of extreme weather events

- Increases stress on populations and forces organisms to shift their geographic ranges

• Most animals and plants will not be able to cope


Warming has been the greatest in the Arctic

The polar bear is being considered for the endangered species list


Biodiversity loss has a variety of causes


Biodiversity provides free ecosystem

services

• Provides food, shelter, fuel

• Purifies air and water, and detoxifies wastes

• Stabilizes climate, moderates floods, droughts, wind, temperature

• Generates and renews soil fertility and cycles nutrients

• Pollinates plants and controls pests and disease

• Maintains genetic resources

• Provides cultural and aesthetic benefits

• Allows us to adapt to change

The annual value of just 17 ecosystem services = $16 - 54 trillion per

year


Biodiversity helps maintain ecosystem

function

• Biodiversity increases the stability and resilience of communities and ecosystems

- Decreased biodiversity reduces a natural system’s ability to function and provide services to our society

• The loss of a species affects ecosystems differently

- If the species can be functionally replaced by others, it may make little difference

- Extinction of a keystone species may cause other species to decline or disappear

• “To keep every cog and wheel is the first precaution of intelligent tinkering” (Aldo Leopold)


Biodiversity enhances food security

• Genetic diversity within crops is enormously valuable

- Turkey’s wheat crops received $50 billion worth of disease resistance from wild wheat

• Wild strains provide disease resistance and have the ability to grow back year after year without being replanted

• New potential food crops are waiting to be used

- Serendipity berry produces a sweetener 3,000 times sweeter than sugar


Some potential new food sources


Organisms provide drugs and medicines

• Each year pharmaceutical products owing their origin to wild species generate up to $150 billion in sales

- The rosy periwinkle produces compounds that treat Hodgkin's disease and leukemia


Biodiversity generates economic benefits

• People like to experience protected natural areas, creating economic opportunities for residents, particularly in developing countries

- Costa Rica: rainforests

- Australia: Great Barrier Reef

- Belize: reefs, caves, and rainforests

• A powerful incentive to preserve natural areas and reduce impacts on the landscape and on native species

• But, too many visitors to natural areas can degrade the outdoor experience and disturb wildlife


People value and seek out nature

• Biophilia = connections that humans subconsciously seek with life

- Our affinity for parks and wildlife

- Keeping of pets

- High value of real estate with views of natural lands

• Nature deficit disorder = alienation from the natural environment

- May be behind the emotional and physical problems of the young


Do we have ethical obligations to other

species?

• Humans are part of nature and need resources to survive

• But, we also have conscious reasoning ability and can control our actions

- Our ethics have developed from our intelligence and our ability to make choices

• Many people feel that other organisms have intrinsic value and an inherent right to exist


Conservation biology responds to

biodiversity loss• Conservation biology =

devoted to understanding the factors that influence the loss, protection, and restoration of biodiversity

- Arose as scientists became alarmed at the degradation of natural systems

- An applied and goal-oriented science


Conservation scientists work at multiple

levels

• Conservation biologists integrate evolution and extinction with ecology and environmental systems- Design, test, and implement ways to mitigate

human impacts• Conservation geneticists = study genetic attributes of

organisms to infer the status of their population• Minimum viable population = 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


Island biogeography

• Equilibrium theory of island biogeography = explains how species come to be distributed among oceanic islands

- Also applies to “habitat islands” – patches of one habitat type isolated within a “sea” of others

- Explains how the number of species on an island results from an equilibrium between immigration and extirpation

- Predicts an island’s species richness based on the island’s size and distance from the mainland


Species richness results from island size and

distance

• Fewer species colonize an island far from the mainland

• Large islands have higher immigration rates

• Large islands have lower extinction rates


The species-area curve

• Large islands contain more species than small islands

- They are easier to find and have lower extinction rates

- They possess more habitats


Small “islands” of forest rapidly lose

species

• Forests are fragmented by roads and logging

• Small forest fragments lose diversity fastest

- Starting with large species

• Fragmentation is one of the prime threats to biodiversity


Should conservation focus on endangered

species?

• Endangered Species Act (1973) (ESA) = forbids the government and private citizens from taking actions that destroy endangered species or their habitats

- To prevent extinction

- Stabilize declining populations

- Enable populations to recover

• As of 2007, the U.S. had 1,312 species listed as endangered or threatened


Despite opposition, the ESA has had

successes• Peregrine falcons, brown pelicans, bald eagles,

and others have recovered and are no longer listed

• Intensive management has stabilized other species

- The red-cockaded woodpecker

- 40% of declining populations are now stable

• These successes occur despite underfunding of the U.S. Fish and Wildlife Service and the National Marine Fisheries Service

- In recent years, political forces have attempted to weaken the ESA


The ESA is controversial

• Many Americans support protection of endangered species

• Opponents feel that the ESA values endangered organisms more than the livelihood of people

- Private land use will be restricted if an endangered species is present

- “Shoot, shovel, and shut up” = landowners conceal the presence of endangered species on their land

• But, the ESA has stopped few development projects

- Habitat conservation plans and safe harbor agreements = landowners can harm species if they improve habitat for the species in other places


Other countries have their own version of

the ESA

• Species at Risk Act (2002) = Canada’s endangered species law

- Stresses cooperation between landowners and provincial governments

- Criticized as being too weak

• Other nations’ laws are not enforced

- The Wildlife Conservation Society has to help pay for Russians to enforce their own anti-poaching laws


Protecting biodiversity

• Captive breeding – individuals are bred and raised with the intent of reintroducing them into the wild

- Zoos and botanical gardens

• Some reintroductions are controversial

- Ranchers opposed the reintroduction of wolves to Yellowstone National Park

- Some habitat is so fragmented, a species cannot survive


Protecting biodiversity

• Cloning – a technique to create more individuals and save species from extinction

- Most biologists agree that these efforts are not adequate to recreate the lost biodiversity

• Ample habitat and protection in the wild are needed to save species


Umbrella species

• Conservation biologists use particular species as tools to conserve communities and ecosystems

- Protecting the habitat of these umbrella species helps protect less-charismatic animals that would not have generated public interest

• 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 single species approach to focus on whole landscapes


International conservation efforts

• UN Convention on International Trade in Endangered Species of Wild Fauna and Flora (1973) (CITES) – protects endangered species by banning international transport of their body parts

• Convention on Biological Diversity (1992) –

- Seeks to conserve biodiversity

- Use biodiversity in a sustainable manner

- Ensure the fair distribution of biodiversity’s benefits

- By 2007, 188 nations had signed on

- Iraq, Somalia, the Vatican, and the U.S. did not join


Biodiversity hotspots

• Biodiversity hotspots –prioritizes regions most important globally for biodiversity

- 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)

- It must have lost 70% of its habitat due to human impact


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


Community- based conservation

• Protecting habitats makes good sense, but this affects people living in and near these areas

• Community-based conservation = conservation biologists actively engage local people in protecting land and wildlife

- Protecting land deprives people access to resources

- But, it can guarantee that these resources will not be used up or sold to foreign corporations and can instead be sustainably managed

• Many projects have succeeded

- But, others have not, due mainly to funding problems


Innovative economic strategies

• Debt-for-nature swap = a conservation organization pays off a portion of a developing country’s international debt

- In exchange for a promise by the country to set aside reserves

- Fund environmental education, and

- Better manage protected areas

• Conservation concession = conservation organizations pay nations to conserve, and not sell, resources


Conclusion

• Loss of biodiversity will result in a mass extinction

• Primary causes of biodiversity loss are:

- Habitat alteration, invasive species, pollution, overharvesting of biotic resources, and climate change

• Human society cannot function without biodiversity’s benefits

• Science can help save species, preserve habitats, restore populations, and keep natural ecosystems intact


QUESTION: ReviewWhich level is NOT included in the concept of biodiversity?

a) Speciesb) Geneticsc) Ecosystemsd) All of the above are included in this concept


QUESTION: Review

What happens when a species experiences “inbreeding depression”?

a) The species becomes too large for the resource baseb) Genetically similar parents mate and produce inferior

offspringc) Genetically similar parents mate and produce

superior offspringd) The number and variety of species increases


QUESTION: Review

According to the concept of “latitudinal gradient,” which of the following happens?

a) Species richness increases towards the equatorb) Species richness decreases towards the equatorc) Species richness decreases over timed) Countries like Canada have many more species than

expected


QUESTION: Review

Which of the following is the major cause of extinction?

a) Invasive speciesb) Pollutionc) Habitat lossd) Overharvesting


QUESTION: Review

Biodiversity does all of the following, except…

a) Provide ecosystem servicesb) Decrease food securityc) Maintain ecosystem functiond) Provide aesthetic benefits


QUESTION: Review

According to the theory of island biogeography, which island would have the highest species richness?

a) A large island, close to the mainlandb) A large island, far from the mainlandc) A small island, close to the mainlandd) A small island, far from the mainland


QUESTION: Review

A “biodiversity hotspot” is…?

a) An area located near the equatorb) An area that supports few, but large, speciesc) An area that contains naturally high numbers of

peopled) An area that contains a large number of endemic

species


QUESTION: Weighing the Issues

If a pharmaceutical company produces a medicine from a plant found in Costa Rica that will earn millions of dollars, who should reap the financial benefits?

a) The company, because it produced the drugb) Costa Rica, because it had the plant that produced the drugc) Taxpayers, because they fund lots of research through their

tax dollarsd) Both the company and Costa Rica, because both played a vital

part


QUESTION: Weighing the Issues

Have you ever personally experienced evidence of

the biophilia hypothesis?

a) Yes, I frequently feel a connection to other living things and nature

b) Yes, sometimes, on a particularly lovely dayc) Maybe, but I’m not sure d) Definitely not, unless I was earning money

from using nature


QUESTION: Interpreting Graphs and Data

Where would ecotourists go to view the maximum species richness on these islands?

a) Redonda

b) Montserrat

c) Puerto Rico

d) Hispaniola


QUESTION: Interpreting Graphs and Data

Which biome lost the most area by 1950; which biome lost the most area in recent decades?

a) Temperate

grassland; tropical

dry forest

b) Desert; savanna

c) Chaparral; tundra

d) Temperate

grassland; desert

Documents

Ch 11 - Wikispaces 11 Biodiversity and Conservation Biology ... Bengal tiger = Panthera tigris ... Copyright © 2008 Pearson Education, Inc.,