Introduction of Exotic Species

Most species do not survive when introduced into different habitats because they have specialized habitat requirements. Others do well and most of our invasive species are very effective in competing for limited resources with native species.

OPTIMUM ENVIRONMENT

Species absent

Species absent

Optimal rangeAbundant species

Stress zone

Stress zone

Fewer species

Fewer species

Classic example of an invasive species – considered by some to be the biggest threat to biodiversity conservation (this is a western world view)

Pet parrots, Amazon Brazil, TROPICAL FORESTS Photo: K Vogt

Protecting biodiversity conflicts with indigenous community’s needs to survive and

obtain sufficient food for themselves

Environmental Conservation: Forests,Grasslands, Parks, and Nature Preserves

Chapter 6

Outline:

• Tropical Forests• Temperate Forests

Harvest Methods and Fire Management• Rangelands

Overgrazing and Land Degradation• Parks and Nature Preserves

History - Problems - Size and Design• Wilderness Areas• Wildlife Refuges

Forests, woodlands = 33% land area

Ice, rock, desert etc. = 32%

Range, Pastures = 23%

Ag = 10%

Built land = 2%

FAO 1999,WRI 1998-1999 GLOBE

~ 66% area in RESOURCE EXTRACTION

WORLD FORESTS

• Forests play vital ecological roles: Regulating climate, controlling water

runoff, providing food and shelter for wildlife, and purifying air.

• Provide valuable materials. Wood, paper-pulp.

• Scenic, cultural, and historic value.

World Forests

Forest Products

Forest Management

• Approximately 25% of world’s forests are actively managed for wood production. Sustainable harvest is key to

regeneration.- Many reforestation projects involve

Monoculture Forestry. Rapid growth and easier harvest.

Disrupts ecological processes.

Tropical Forests

• Although they occupy less than 10% of earth’s land surface, tropical rainforests are thought to contain: More than two-thirds of all higher plant

biomass. At least one-half of all plant, animal, and

microbial species in the world.

Tropical Forest Losses

Causes of Deforestation

• Thin, nutrient-poor tropical soils are usually worn out after a few years of cropping. Shifting cultivation often blamed for forest

destruction.- Can be sustainable where population

densities are low and individual plots are allowed to regenerate between cultivation periods.

Debt-for-Nature Swaps

• Banks, governments, and lending institutions hold nearly $1 trillion in loans to developing countries. Conservation organizations buy debt

obligations on the secondary market at a discount, and then offer to cancel the debt if the debtor country will agree to protect or restore an area of biological importance.

Temperate Forests

• Northern countries have a long history of liquidating forest resources. For many years, “multiple use” was the

official policy of the U.S. Forest Service.- Simultaneous uses.

Incompatibility ?

Old-Growth Forests

• Today, less than 10% of the old-growth forest in the United States remains intact. ??? 80% of what is left is scheduled to be

cut down in the near future (in text) ??? NO!!!

• Environmentalists sued U.S. Forest Service over logging rates in WA and OR in 1989. Protection of northern spotted owls. Timber industry claimed 40,000 jobs would

be lost.

Harvest Methods

• Clear-Cutting - Every tree in a given area is cut regardless of size. Fast and efficient, but wastes small trees,

increases erosion, and eliminates wildlife habitat.

• Shelterwood - Remove mature trees in series of cuts.

Harvest Methods

• Strip Cutting - Harvesting all trees in a narrow corridor.

• Selective Cutting - A small percentage of mature trees are taken in 10-20 year rotation. Can retain many characteristics of mature,

old-growth forests.

Loggings and Roads in National Forests

• Increasing number of people in the U.S. are calling for an end to all logging on federal lands. $4 Billion annual harvest vs. estimated

$224 Billion from recreation and ecological function.

• USFS builds roads in order for timber companies to extract trees. Hidden subsidy to timber industry.

Fire Management

• For more than 70 years, firefighting has been a high priority for forest managers. Many communities are fire-adapted. Accumulation of woody debris.

• Forest Service says 40% of all federal forest lands are at risk of severe fires. 68,230 fires burned 2.7 million ha in 2002.

- Firefighting costs of $1.6 Billion.• How to undo years of fuel build-up ?

Ecosystem Management

• 1990’s saw USFS shift from timber production to ecosystem management. Attempts to integrate sustainable

ecological, and social goals in a unified, systems approach.

• USFS is also using - ‘AdaptativeManagement’(trying new science, etc)

RANGELANDS

• Pasture and Open range occupy about 25% of the world’s land surface. More than 3 billion domestic livestock

producing meat and milk.• Attractive and frequently converted to

human-dominated landscapes.

Desertification?

New Approaches to Ranching

• Short-Duration Rotational Grazing Forces livestock to graze equally, trample

ground evenly, and fertilize with manure before moving on.

• Game Ranching Many wild species forage more efficiently,

resist harsh climates, and can fend off predators and pests better than domestic livestock.

PARKS AND NATURE PRESERVES

• Origins and History Historically, sacred groves were set aside

for religious purposes, and grounds preserved for royalty.

- Only in the past 130 years have we begun to preserve wild places for the sake of wildlife and scenic beauty.

Park Problems• Many parks have become islands of nature

surrounded and threatened by destructive land uses stemming from growing human populations crowding park boundaries.

Park rangers often spend more time on crime prevention and crowd control than natural history.

Mining and oil interests push to operate on private inholdings.

Marine Preserves

• Shelter marine organisms from destructive harvest methods. Coral reefs among most threatened marine

ecosystems.- 90% face threats from sea temperature

change, destructive fishing methods, coral mining, sediment runoff and other human disturbance.

Size and Design of Nature Preserves

• Single Large or Several Small (SLOSS) Ideally, a reserve should be large enough

to support viable populations of endangered species, keep ecosystems intact, and isolate critical core areas from external forces.

Conservation and Economic Development

• Tropics are suffering the greatest destruction and species loss in the world. Ecotourism can be more beneficial to

many countries over the long-term than extractive industries – BUT only if done ecologically and not as money making show only.

- Wildlife watching and outdoor recreation can be a welcome source of income for underdeveloped countries.

Indigenous Communities and Reserves

• Areas chosen for nature preservation are often traditional lands of indigenous people. 1986 UNESCO initiated its Man and

Biosphere Program (MAB).- Encourages division of protected areas

into zones with different purposes.

WILDERNESS AREAS

• 1964 - Wilderness Act defined wilderness: “An area of undeveloped land affected

primarily by the forces of nature, where man is a visitor who does not remain…”

Most areas meeting these standards are in the Western US and Alaska.

WILDLIFE REFUGES

• 1901 - President Teddy Roosevelt established 51 national wildlife refuges. Now 511 refuges encompassing 40 million

ha representing every major biome in NA.

Wildlife Refuges

• Over the years, a number of other uses have been allowed to operate within wildlife refuge boundaries. Oil and Gas Drilling Cattle Grazing Motor-boating, Camping

• Refuges also face threats from external sources - expanding human populations. Water Pollution

Summary:

• Tropical Forests• Temperate Forests

Harvest Methods and Fire Management• Rangelands

Overgrazing and Land Degradation• Parks and Nature Preserves

History - Problems - Size and Design• Wilderness Areas• Wildlife Refuges