Maintaining Terrestrial Biodiversity PP.ppt

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Human Impacts on Terrestrial Biodiversity

Human Population

Size and resource use

Human Activities

Agriculture, industry, economic production and consumption, recreation

Direct Effects

Degradation of natural ecosystems

Changes in numbers and distribution of species Alteration of natural chemical cycles and energy flows

Pollution of air, water and soil

Indirect Effects

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Types of US Public Lands

1. National Forest System

2. National Resource Lands

3. National Wildlife Refuges

4. National Park System

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National Forest System

• Forests and grasslands

• Managed by US Forest Service

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National Resource Lands

• Managed by the Bureau of Land Management

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National Wildlife Refuges

• Managed by US Fish and Wildlife Service

• Protect habitats and breeding areas for water fowl and big game • Some protect endangered species

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National Park System

• Managed by the

National Park Service

• Includes major parks

and national

recreation areas,

monuments,

parkways, trails, river,

seashores,

lakeshores

• Camping, hiking,

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National Wilderness Preservation System

• Lie within other types of public lands

• Managed by agencies in charge of those lands

• Only used for recreational activities such as

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Managing US Public Lands

Conservation Biologists say:

• Protecting biodiversity should be primary goal

• No government subsidies for extracting resources

• American people deserve fair compensation for extraction of resources

• All users or extractors of resources on Public Lands should be liable for any

environmental damage they cause

Developers and Extractors say: • Sell Public Lands/resources to

corporations or individuals at less than fair market prices • Slash federal funding for

regulatory administration of public lands

• Open all national parks, wildlife refuges, wilderness areas to oil drilling, development, etc

• Abolish National Park Service • Repeal ESA

• Redefine wetlands so 50% of them will no longer be

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Managing and Sustaining Forests

Major Types of Forests

1. Old-growth forest – uncut or regenerated, not

disturbed by human activities for >200 years.

Store-houses of biodiversity – many niches

2. Second-growth forest- results from secondary

succession. Develops after human activities or

natural forces.

3. Tree plantation (tree farm)- uniformly aged

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Types of Forest Management

1. Even-aged Management

(industrial forestry)

maintaining trees at about same

age/size. Harvested every 6-10

years

2. Uneven-aged management

variety of trees at many

ages/sizes – fosters natural

regeneration. Goal of

biodiversity/sustainability

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Harvesting Trees

• First step - road building

• Leads to increased erosion and

sedimentation of waterways

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Methods of Harvesting Trees

1. Selective cutting

2. Shelterwood cutting

3. Seed-tree cutting

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Selective Cutting

• Intermediate aged or matures trees in uneven-aged

forest are cut singly or in small group.

• Reduces crowding, encourages growth of younger trees

• Allows natural regeneration

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Shelterwood Cutting

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Seed-tree Cutting

• Harvests all of a stand’s trees in one cutting, but leaves a few uniformly distributed

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Clear Cutting

• Removes all trees from an area in a single cutting

• Advantages: higher timber yields, maximum economic return, can

reforest with genetically improved trees, needs less time to establish new stand of trees, best way to harvest tree plantations

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Strip Cutting

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Ecological/Economical Services of Forests

Ecological Services

1. Energy flow/chemical

cycling

2. Reduce soil erosion

3. Absorb and release

water

4. Purify water

5. Purify air

6. Influence climate

7. Carbon sink

8. Wildlife habitats

Economic Services

1. Fuelwood

2. Lumber

3. Pulp for paper

4. Mining

5. Livestock grazing

6. Recreation

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Harmful Effects of Deforestation

• Deforestation – temporary or permanent removal of large expanses of forest for agriculture or other uses.

• Decreased soil fertility from erosion, increased sedimentation, premature extinction of species with specialized niches, loss of

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Managing Forests More Sustainably

• Grow more timber on long rotations

• Use selective and strip cutting

• No clear cutting, seed-tree, or shelterwood cutting

• Reduce road building into uncut forest areas

• No fragmentation of remaining large blocks of forest

• Leave standing dead trees and fallen timber for wildlife

habitat and nutrient recycling

• Certify timber grown by sustainable methods

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Reducing Damage from Insects/Pathogens

• Inspect imported timber (to reduce nonnative species introductions) • Remove disease and infected trees

• Use conventional pesticides and biological controls to combat insects

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Fire Effects on Forests

Three types of fires affecting US forests:

1. Surface fires

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Surface Fire

• Burns undergrowth and leaf litter

• _{Spares most mature trees and allows}

wildlife to escape

• Ecological benefits include: help prevent

more destructive fires, release valuable

mineral nutrients, stimulate the

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Crown Fires

• Starts on the ground, but eventually burns whole trees and leaps from treetop to treetop.

• Usually occur in forests that have had no surface fires for several decades. Allows dead wood, leaves, and other flammable litter to build up.

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Ground Fire

• A surface fire that

goes underground

and burns partially

decayed leaves or

peat.

• Common in northern

peat bogs

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Reducing Damage from Forest Fires

1. Prevention: require

burning permits,

close all parts of a

forest during

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Smokey the Bear

Pros

• Prevented countless

forest fires

• Saved lives

• Prevented billions of

dollars in losses of

trees, wildlife, and

human structures

Cons

• Convinced public that

all forest fires are

bad/ should be

prevented

• Ecologists say

preventing all fires

increases likelihood of

destructive crown

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Reducing damage

2. Prescribed burning: set small surface

fires to clear out flammable small trees

and underbrush.

Requires careful planning/monitoring

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Reducing the need for timber and

papermaking

• Improve the efficiency of wood use – 60%

of wood consumed in US is wasted due to

excess packaging, over use of junk mail,

inadequate paper recycling, inefficient use

of construction materials

• Use kenaf (rapidly growing woody annual)

to make paper. Kenaf – nitrogen fixer,

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Tropical Deforestation

• Cover about 6% of

earth’s land area

• Being cut rapidly in

South America

(Brazil)

Asia, Africa

• Brazil’s original

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Importance of Tropical Rainforests

• Provides blueprint for

making most of

world’s prescription

drugs

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Causes of Tropical Deforestation

Primary Causes

• Population growth

• Poverty

• Harmful government subsidies

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Secondary Causes

• Oil drilling

• Mining

• Flooding from dams

• Tree plantations

• Cattle ranching

• Cash crops

• Farming

• Fires

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Reducing Tropical Deforestation

through Prevention

• Help settlers in tropical forests practice

sustainable agriculture/forestry

• Use strip cutting

• Sustainably harvest renewable resources

such as fruits and nuts

• Debt for nature swaps-developing countries

protect the forests in exchange for debt

reduction

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Reducing Tropical Deforestation Through

Restoration

• Reforestation – Neem

Tree

• Rehabilitation of

degraded areas

• Concentrate farming

and ranching on

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Why Neem Tree?

• Quickly reforests degraded land

• Supplies fuelwood and lumber in dry areas

• Provides natural alternative to toxic pesticides

• Medicinal – fights bacterial, viral and fungal infections,

strong spermicide (may help in development of male birth

control pill.)

• Ecologists urge caution in

planting outside native range – could become an invasive

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National Parks in US

Threats include:

• _{off-road vehicles, dirt bikes,}

snowmobiles destroy vegetation and

disrupt wildlife

• _{Introduction of nonnative species}

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Solutions for National Parks

• Add new park land near threatened parks

• Use shuttle buses for entering and touring

heavily used parks

• Raise entry fees for visitors and use funds

for park maintenance/management

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Nature Reserves

• Ecologists and Conservation Biologists believe

we should preserve biodiversity through a

worldwide network of protected areas.

• Examples: parks in Amazon River Basin,

reserves and national parks in Costa Rica

• Nature Conservancy uses private/corporate

donations to create private natural areas and

wildlife sanctuaries.

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