Chapter 10: Sustaining Terrestrial Biodiversity

The Ecosystem ApproachCase Study: The Reintroduction of the Gray Wolf to Yellowstone

Why Should We Care About Biodiversity? Intrinsic Value Instrumental Value

Use Value: For the usefulness in terms of economic and ecological services.

Nonuse Value: existence, aesthetics, bequest for future generations.

Figure 10-3Figure 10-3

Types of Forests Old-growth forest: uncut or

regenerated forest that has not been seriously disturbed for several hundred years. 22% of world’s forest. Hosts many species with

specialized niches.

Figure 10-5Figure 10-5

Types of Forests

Second-growth forest: a stand of trees resulting from natural secondary succession.

Tree plantation: planted stands of a particular tree species.

Figure 10-6Figure 10-6

Animation: Hubbard Brook Experiment

PLAYANIMATION

Forest Benefits1. Influence local climates:

cooler and moister due to transpiration

2. Global biogeochemical cycles: provide a sink for CO2

3. Release O2

4. Roots hold soil: reduce erosion

5. Watershed protection: absorb, hold and slowly release water, controlling floods

6. Provide habitat for many organisms

Tropical Deforestation Agriculture Logging Mining Hydroelectric power development

Tropical Deforestation: Causes

Fig. 11-18 p. 212

Reducing Tropical Deforestation

Refer to Fig. 11-19 p. 213

Reducing poverty and population growth

Reduce illegal cutting

Debt-for-nature swaps

Sustainable tropical agriculture

Encourage protection of large tracts

Amazon Rainforest

Satellite image of deforestation in the Amazon region, taken from the Brazilian state of Para on July 15, 1986.

http://www.bsrsi.msu.edu/rfrc/index.html

Boreal Deforestation Alaska, Canada, Scandinavia, North Russia 11% of earth’s land area – world’s largest biome Frequently clear cut Primary source of industrial wood and wood

fiber Annual loss twice the Amazonian rainforest of

Brazil

Temperate Forests Have been holding steady or increasing in recent

years Biodiversity lower than in virgin forests Reasons include:

Secondary succession of abandoned farms Commercial planting Government protection

Results of Deforestation1. Threatens native people and cultures2. Decreased soil fertility3. Soil erosion4. Increased sedimentation in streams5. Formation of deserts in dry areas6. Unregulated water – droughts and floods7. Species extinction8. Migrating species affected9. Regional and global climate change10. Increased CO2 in atmosphere

Selective Cutting The hard maple forest is

managed under a selection system. Individual trees are harvested from stands on a 28 year cycle. Specific trees are retained in these stands for biodiversity and wildlife habitat purposes.

Selective Cutting

Clear cutting

Clear cutting

Ten year old clear cut – Tongass National Forest, AlaskaUS FS photo 1979

Western Red cedar stump, Washington USFS photo

Logging debris in creek, Umpqua National Forest, Oregon USFS photo

Planting after clear cut – Jack Pine

Tree Plantation – one species and even aged stand

Shelterwood Cutting

Shelterwood Cutting – Lake Superior

Strip Cutting Forestry in Idaho

Types and Effects of Forest Fires

Depending on their intensity, fires can benefit or harm forests. Burn away flammable ground material. Release valuable mineral nutrients.

Figure 10-13Figure 10-13

Kenya’s Green Belt Movement:Individuals Matter

Wangari Maathai founded the Green Belt Movement.

The main goal is to organize poor women to plant (for fuelwood) and protect millions of trees.

In 2004, awarded Nobel peace prize.

Figure 10-10AFigure 10-10A

The Green Belt Movement Wangari Maathai

talks about the Billion Tree Campaign Earth Focus: Wangari Maathai