Sustaining Biodiversity:  The Ecosystem Approach

Chapter 6


Human Activities and Biodiversity

Global Biodiversity Status

Importance of Biodiversity

•  Intrinsic value

•  Instrumental value

•  Existence value

•  Aesthetic value

•  Bequest value


Solutions for Protecting Biodiversity


US Public Lands


Ecological and economic services of forests

Logging in U.S. National Forests


Helps meet country’s timber needs

Cut areas grow back

Keeps lumber and paper prices down

Provides jobs in nearby communities

Promotes economic growth in nearby communities



Provides only 4% of timber needs

Ample private forest land to meet timber needs

Has little effect on timber and paper prices

Damages nearby rivers and fisheries

Recreation in national forests provides more local jobs and income for local  communities than logging

Decreases recreational opportunities



Higher timber yields

Maximum economic return in shortest time

Can reforest with genetically improved fast-growing trees

Short time to establish new stand of trees

Needs less skill and planning

Best way to harvest tree plantations

Good for tree species needing full or moderate sunlight for growth



Reduces biodiversity

Disrupts ecosystem processes

Destroys and fragments some wildlife habitats

Leaves moderate to large openings

Increases soil erosion

Increases sediment water pollution and flooding when done on steep slopes

Eliminates most recreational value for several decades


Sustainable Forestry

•Longer rotations

•Selective or strip cutting

•Minimize fragmentation

•Leave wildlife snags and logs

•Improved road building techniques

•Certify sustainable grown

•Include ecological services in estimating economic value


Green Tree Retention:
Dispersed vs Aggregated

Pros and cons of each?

Tropical Deforestation: Consequences

•Rapid and increasing

•Loss of biodiversity

•Loss of resources (e.g., medicines)

•Contributes to global warming



Managing and Sustaining National Parks

•Inadequate protection

•Often too small to sustain biodiversity

•Invasions by nonnative species

•Too many human visitors

•Traffic jams and air pollution

•Better pay for park staff


Establishing, Designing, and Managing Nature Reserves

•Include moderate to large tracts of land

•Involve government, private sector and citizens

•Biosphere reserves

•Adaptive ecosystem management

•Protect most important areas (“hot spots”)

•Wilderness areas


Managing Fisheries

Fishery Regulations

Set catch limits well below the maximum sustainable yield

Improve monitoring and enforcement of regulations

Economic Approaches

Sharply reduce or eliminate fishing subsidies

Charge fees for harvesting fish and shellfish from publicly owned offshore waters

Certify sustainable fisheries

Protected areas

Establish no-fishing areas

Establish more marine protected areas

Rely more on integrated coastal management

Consumer Information

Label sustainably harvested fish

Publicize overfished and threatened species



Use wide-meshed nets to allow escape of smaller fish

Use net escape devices for seabirds and sea turtles

Ban throwing edible and marketable fish back into the sea


Restrict coastal locations for fish farms

Control pollution more strictly

Depend more on herbivorous fish species

Nonnative Invasions

Kill organisms in ship ballast water

Filter organisms from ship ballast water

Dump ballast water far at sea and replace with deep-sea water


Ecological Restoration: Basic Principles

•Mimic nature

•Recreate lost niches

•Rely on pioneer species

•Control nonnative species

•Reconnect small patches


Dr. Wangari Maathai
and Kenya’s Green Belt Movement

•founded in 1977

•responding to needs identified by rural women: lack of firewood, clean drinking water, balanced diets, shelter and income.

•raise and plant tree seedlings

•50,000 members

•6,000 village nurseries

•30 million trees

•2004 Nobel Peace Laureate

•“sustainable development, democracy and peace are indivisible”





Sustaining Biodiversity: The Species Approach

Chapter 7

Species Extinction

•Local extinction

•Ecological extinction

•Biological extinction

Endangered and Threatened Species

•Endangered species

•Threatened (vulnerable) species

Characteristics of Extinction Prone Species

Problems Estimating Extinction Rates

•Extinction not easily documented over time

•Many species remain unidentified

•Little is known about most identified species


Causes of Premature Extinction of Wild Species

Importance of Wild Species

•Rebuilding biodiversity is slow

•Instrumental value

•Genetic information


•Ecological value

•Intrinsic value

Pharmaceuticals from plants

Habitat Loss and Degradation

ΨGreatest threat to species


ΨHabitat destruction

ΨInvasive species

ΨPopulation (humans) growth




Threats from Nonnative Species

Intentionally introduced species

Accidentally introduced species

Other Extinction Threats

•Hunting and Poaching

•Predators and Pest Control

•Exotic Pets and Decorative Plants

•Climate Change and Pollution

Bioaccumulation and Biomagnification

•Persistent (non-biodegradable) toxins build up in an animal over time = bioaccumulation

•Become more concentrated at higher trophic levels = biomagnification

Protecting Wild Species:  The Research and Legal Approaches

•International Treaties:  CITES and CBD

•U.S. National Laws:  

•Lacey Act

•Endangered Species Act

•Habitat recovery plans

Endangered Species Act

•Private versus public poverty rights

•Win-win compromises

•Weaken or strengthen the Act?

Protecting Wild Species:  The Sanctuary Approach

•Wildlife refuges and protected areas

•Gene banks, botanical gardens, and farms

•Zoos and Aquariums


Reconciliation Ecology

•Establishing and maintaining new habitats

•Being good neighbors to wildlife

•Reward voluntary conservation efforts

Conservation: What Can I Do?