Conservation of Biodiversity

Chapter 40

Conservation biology • Biodiversity!!• Emerged in response to a crisis

– At least 10–20% of all species now living most likely will become extinct in the next 20–50 years

• Bioinformatics

Conservation biology

• Supports following ethical principles:– Biodiversity is desirable for the

biosphere and, therefore, for humans– Extinctions, due to human actions, are

undesirable– Complex interactions in ecosystems

support biodiversity and are desirable– Biodiversity from evolutionary

standpoint has value in and of itself, regardless of practical benefit

Biodiversity• Variety of life on Earth

– Between 10 and 50 million species may exist

• Extinction– Of the described species,

nearly 1,200 in the United States and 40,000 worldwide are in danger of extinction

• Endangered species

• Threatened species

Understanding Biodiversity• Genetic diversity

– variations among the members of a population • Ecosystem diversity

– dependent on interactions of species at a locale– Conserve species that play a critical role in an ecosystem– Saving an entire ecosystem can save many species

• Landscape diversity – interacting ecosystems within one landscape– Fragmentation reduces can disrupt seasonal behaviors

• Distribution of Biodiversity – Biodiversity not evenly distributed throughout the

biosphere– biodiversity hotspots

• contain unusually large concentrations of species

Disrupted ecosystem in Flat-head Lake, Montana

Direct Value of Biodiversity

• Wildlife Has Medicinal Value – Most prescription

drugs in the United States originally derived from living organisms

Direct Value of Biodiversity

• Wildlife Has Agricultural Value – Crops are derived

from wild plants that have been modified

– Biological pest controls are often preferable to chemical pesticides

Direct Value of Biodiversity

• Wildlife Has Consumptive Use Value– freshwater and marine

harvests depend on the catching of wild animals

– Provides a variety of other products that are sold in the marketplace worldwide

Indirect Value of Biodiversity

• Biogeochemical Cycles Dispose of Waste – Biodiversity contributes to workings of water, carbon,

phosphorus, and nitrogen cycles• Natural Areas Provide Fresh Water, Prevent Soil

Erosion, and Regulate Climate – Water-holding capacity of forests and wetlands reduces the

possibility of flooding – Intact ecosystems naturally retain soil and prevent erosion

• Ecotourism Is Enjoyed by Many– In U.S., people spend $4 billion each year on ecotourism

Wildlife Extinctions

• Habitat loss• Introduction of

alien species• Pollution• Overexploitation• Disease

1. Habitat loss

• 1,880 threatened and endangered species in U.S.

• 85% of cases• Focus on tropical rain forests

and coral reefs • Loss of habitat also affects

freshwater and marine biodiversity– Coastal degradation mainly due

to the large concentration of people living on or near the coast

– 60% of coral reefs have been or are on verge of destruction

2. Alien Species• Nonnative members brought

into new ecosystems through• Colonization

– Europeans brought various familiar species with them when they colonized new places

• Horticulture and agriculture – Aliens have escaped from

cultivated areas• Accidental transport

– Global trade and travel• Aliens on Islands

– Islands are particularly susceptible to environmental discord caused by the introduction of alien species

2. Alien Species

• Everglades National Park, Florida– Pythons– Caiman– Wooly rat– Monitor lizards

3. Pollution• Environmental change that

damages lives and health of organisms

• Acid deposition – sulfur dioxide from power

plants – nitrogen oxides in

automobile exhaust – converted to acids when

they combine with water vapor in the atmosphere

• Eutrophication – Overenrichment– algae blooms occur and

upon death, the decomposers break down the algae

• in so doing, they use up oxygen

3. Pollution• Ozone depletion

– Ozone shield absorbs most of the wavelengths of harmful ultraviolet (UV) radiation so they do not strike the Earth

• Organic chemicals – used in products ranging from

pesticides to dishwashing detergents, cosmetics, plastics, etc

• Global warming ****– A 1 meter rise in sea level

could inundate 25–50% of U.S. coastal wetlands

– Bleaching coral reefs

4. Overexploitation • Number of individuals taken from a

wild population so great that the population becomes severely reduced in number

• Positive feedback cycle – Smaller population– Greater incentive to capture few

remaining organisms• Poachers

• Overexploited 11 of 15 major oceanic fishing areas– Fish are a renewable resource – More efficient fishing fleets to

decimate fishing stocks

5. Diseases

• Due to encroachment of humans on habitat and other general interventions

• Pollution can weaken organisms – more susceptible to

disease• May be due to alien

species– Chytrid fungus

Conservation Techniques

• Habitat Preservation• Habitat Restoration

Habitat Preservation• Keystone species

– influence the viability of a community

– Extinction of a keystone species can lead to other extinctions and a loss of biodiversity

• Metapopulation– population subdivided into

several small, isolated populations

– Habitat fragmentation by humans

• Landscape Preservation– Landscape protection for

one species is often beneficial for other wildlife that share the same space

Habitat Restoration

• Restoration ecology – Subdiscipline of conservation biology– Seeks scientific ways to return ecosystems to

former state– Three principles have so far emerged:

• It is best to begin as soon as possible before remaining fragments of the original habitat are lost

• Once the natural history is understood, it is best to use biological techniques that mimic natural processes to bring about restoration

• Goal is sustainable development, ability of an ecosystem to maintain itself while providing services to human beings

Habitat Restoration

• The Everglades– Located in southern Florida– Beginning of 20th century,

settlers began to drain land to grow crops

– A restoration plan has been developed that will sustain the Everglades ecosystem, while maintaining the services society requires

– The Everglades is to receive a more natural flow of water from Lake Okeechobee

Global Climate Change

• Emissions of greenhouse gases are accelerating

• From 2000–2005 global CO2 emissions increased four times faster than in the preceding 10-year span

Climate Change

• In many plants and animals, life cycle events are triggered by– Warming temperatures – Day length

• As global temperatures warm, and day length remains steady, natural interactions may become out of sync– Plants may bloom before pollinators have emerged– Eggs may hatch before dependable food sources are

available

Human Impact on Biomes

• Sustainability • goal of developing, managing, and conserving Earth’s

resources

• meet the needs of people today without compromising the ability of future generations to meet their needs

20011975

Figure 18.39

The Greenhouse Effect and Global Warming

• Greenhouse gases– Include CO2, water vapor, and methane

– Are transparent to solar radiation– Absorb or reflect heat– Contribute to increases in global temperatures

Atmosphere

Sunlight

Some heatenergy escapesinto space

Radiant heattrapped bygreenhouse gases

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Looking to Our Future

– Emissions of greenhouse gases are accelerating.

– From 2000–2005 global CO2 emissions increased four times faster than in the preceding 10-year span.

– In addition, eating locally grown fresh foods may lower the greenhouse gas emissions that result from food processing and transportation.

Our future?

• carbon (ecological) footprint– amount of greenhouse gas emitted as the

result of the actions of a single individual – reduce our carbon footprints by:

• Reducing our use of energy• Driving less• Recycling