CHAPTER 11

Biodiversity and Conservation Biology

This lecture will help you understand:

• The scope of Earth’s biodiversity

• Ways to measure biodiversity

• Background rates and mass extinction

• Primary causes of biodiversity loss

• The benefits of biodiversity

• Conservation biology

• Island biogeography theory

• Biodiversity conservation efforts

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HOUSEKEEPING ITEMS

Any highlights from the video and/or the discussion on hunting? Thanks to Jasmine, Anthem, and Norranda in Section 1 for their assistance.

SOLUTIONS meeting Monday at 4 (250, Rm. 308) Did anyone go see “No Impact Man”? I put some material in the folder about sources for

local food, including some heirloom or heritage varieties.

We will do the quiz next week, but will do a review beforehand.

to start off today's lecture topic, a short video about a lion: http://www.youtube.com/watch?v=btuxO-C2IzE

Saving the Siberian tiger

“Except in pockets of ignorance and malice, there is no longer an ideological war between conservationists and developers. Both share the perception that health and prosperity decline in a deteriorating environment. They also understand that useful products cannot be harvested from extinct species.” – Edward O. Wilson, Harvard University Biodiversity Expert

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Saving the Siberian tiger

• The largest cat in the world remains only in the Russian Far East mountains

• Almost extinct from hunting, poaching and habitat destruction

• International conservation groups saved the species from extinction

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Biodiversity encompasses several levels• Biodiversity = sum total of all

organisms in an area

- Species diversity

- Genetic diversity

- Ecosystem diversity

FIGURE 9.19-6

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

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The taxonomy of species• Taxonomists = scientists who classify species using

physical appearance and genetics

- Domain- Kingdom- Phylum- Class- Order- Family- Genus- Species

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

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Genetic diversity

• All species consist of individuals that vary genetically from one another to some degree

• Encompasses the varieties in DNA among individuals within species and populations

• The raw material for adaptation to local conditions

• Populations with low genetic diversity are vulnerable

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

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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

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Some groups contain more species than others

• 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

FIGURE 9.4

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Insects outnumber all other species

FIGURE 9.5

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Biodiversity is unevenly distributed

• Latitudinal gradient = species richness increases towards the equator

• Plant productivity and climate stability play key roles

FIGURE 9.6 9-13

Latitudinal gradient has many causes

FIGURE 9.7

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Biodiversity loss and species extinction

• Canadian Species at Risk Act uses categorizes:

- 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

- Endangered = species in imminent danger of becoming extirpated or extinct

- Threatened = species likely to become endangered in the near future

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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

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Earth has experienced five previous mass extinction episodes• In the past 440 million years, mass extinctions have

eliminated at least 50% of all species

• Today’s mass extinction is caused by humans and humans will suffer as a result of it

FIGURE 9.89-17

Humans set the sixth mass extinction in motion years ago

Extinctions followed human arrival on islands and continents

FIGURE 9.9

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Current extinction rates are much 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 to 86% of all other species

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

- Actual numbers are undoubtedly higher

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Biodiversity loss is more than extinction

• The Living Planet Index quantifies degradation

- Between 1970 and 2003, the Index fell by 40%

FIGURE 9.109-20

There are several major causes of biodiversity loss

• Reasons for biodiversity losses are multifaceted and factors may interact synergistically

• Causes of population decline:

- Habitat alteration

- Invasive species

- Pollution

- Overharvesting

- Climate change

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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

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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

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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

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Overharvesting causes biodiversity loss

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

- The Siberian tiger (The 1989 political freedom in Soviet Union brought the freedom to hunt)

- Atlantic gray whale

- Sharks

- Gorillas

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Climate change causes biodiversity loss

• Global impact on habitat and biodiversity

• Greenhouse gases 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, as evolution has been about adaptation genetically over much more slowly-evolving time periods.

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Warming has been the greatest in the Arctic

FIGURE 9.13

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Biodiversity provides ecosystem services free of charge

• 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 to 54 trillion per year

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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

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

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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

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Organisms provide drugs and medicines• Each year

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

FIGURE 9.15 9-31

Biodiversity provides economic benefits through tourism and recreation

• Ecotourism is particularly beneficial in developing countries

- Costa Rica: rainforests

- Australia: Great Barrier Reef

- Belize: reefs, caves, and rainforests

• Incentive to preserve natural areas and reduce impacts on the landscape and on native species

• Too many visitors can degrade the outdoor experience and disturb wildlife

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People value and seek out connections with 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

- evidence suggest that lack of contact also exacerbates ADD and violence

FIGURE 9.16

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Do we have ethical obligations toward other species?

• Humans are part of nature and need resources to survive

• 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. This is reflected in “deep ecology” and the animal rights movement.

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Biophilia and nature deficit disorder

• What do you think of the concepts of biophilia and “nature deficit disorder”?

• Have you ever felt a connection to other living things that you couldn’t explain in scientific or economic terms?

• Do you think that an affinity for other living things is innately human?

• How could you determine whether or not most people in your community feel this way?

weighing

the issues

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Conservation biology arose in response to biodiversity loss

• Conservation biology = devoted to understanding the factors that influence the loss, protection, and restoration of biodiversity

- An applied and goal-oriented science

FIGURE 9.17

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Conservation biologists work at multiple levels

• Use field data, lab data, theory, and experiments to study impacts of humans on other organisms

• Design, test, and implement ways to mitigate impacts

• 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

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Island biogeography theory

• 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

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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

FIGURE 9.18

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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

FIGURE 9.19

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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

FIGURE 9.20

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Captive breeding, reintroduction, and cloning are single-species approaches

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

- Zoos and botanical gardens

• Some reintroductions require international cooperation

- Whooping cranes in Wood Buffalo Park (Canada) and gulf coast of Texas (U.S.)

• Some habitat is so fragmented, a species cannot survive once reintroduced

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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

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Fragmentation and biodiversity

Suppose a critic of conservation tells you that human development increases biodiversity, pointing out that when a forest is fragmented, new habitats, such as grassy lots and gardens, may be introduced to an area and allow additional species to live there.

• How would you respond?

weighing

the issues

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Umbrella species

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

- helps protect less-charismatic animals

• 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

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Both national and international conservation efforts are widely supported

• 2002: Species at Risk Act stresses cooperation with landowners and governments to avoid hostility

• COSEWIC (Committee on the Status of Endangered Wildlife in Canada) = expert committee that reports the status of species at risk

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

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Other approaches highlight areas of high biodiversity

• 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 1500 endemic plant species (0.5% of the world total)

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

FIGURE 9.22

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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

FIGURE 9.23

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Community- based conservation is increasingly popular

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

- Protecting land deprives people access to resources

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

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Innovative economic strategies are being employed

• 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

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Conclusion

• Loss of biodiversity threatens to 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 pragmatic benefits

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

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

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

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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

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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

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QUESTION: Review

Which of the following is the major cause of extinction?

a) Invasive speciesb) Pollutionc) Habitat lossd) Overharvesting

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QUESTION: Review

Biodiversity does all of the following, except…

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

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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

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QUESTION: ReviewA “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

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QUESTION: Interpreting Graphs and Data

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

a) Redondab) Montserratc) Puerto Ricod) Hispaniola

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