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Chapter 12

BIODIVERSITY:

PRESERVING

LANDSCAPES

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OUTLINE

• WORLD FORESTS

DEFORESTATION

OLD GROWTH

HARVEST METHODS

• GRASSLANDS

• PARKS AND PRESERVES

TERRESTRIAL

MARINE

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WORLD FORESTS

• A FOREST is any area where trees cover more than 10% of the land.

SAVANNAS - trees cover less than 20% of ground

CLOSED CANOPY - tree crowns cover most of ground

• Most remaining forests are in tropical and boreal (taiga) regions.

• Highest rates of forest loss in Africa and South America

• Largest tropical forest is the Amazon

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WORLD FORESTS ECOLOGICAL SERVICES

• CARBON SINK for carbon dioxide

• MOISTURE from transpiration contributes to

global rainfall. (water cycle)

• OLD GROWTH FORESTS - cover large areas

and have been undisturbed by humans long

enough that trees can live out a natural life

cycle and ecological processes are normal

Home to much of world’s biodiversity,

endangered species and indigenous people

¾ found in Russia, Canada, Brazil,

Indonesia, Papua New Guinea

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WORLD FORESTS ECOLOGICAL SERVICES

• Habitat for species which creates utilitarian uses:

camping, bird watching, hunting

• Cool air surrounding the forest by

evapotranspiration and shade

• Forests serve as watersheds

• Parts of biogeochemical cycles

(especially: nitrogen/carbon/water)

• Roots reduce runoff and decrease erosion

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GLOBAL LAND USE

Other: cities, arid

areas, tundra

& wetlands

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MAJOR FOREST TYPES

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UTILITARIAN FOREST USES

• WOOD AND PAPER

Developed countries provide less than half of industrial wood, but 80% of consumption.

Paper pulp is 1/5 of all wood consumption.

In developing countries fuel (wood/charcoal) accounts for 1/2 of global wood use.

One quarter of world’s forests are managed for wood production, much of it in single species monoculture forestry.

Many developing countries sell exotic woods (teak, mahogany) to developed countries.

Mining and rangeland use also damage forests

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FOREST MANAGEMENT

• FOREST MANAGEMENT: science of

maintaining a forest for sustainable harvests

• EVEN-AGED: all trees are same size/age

MONOCULTURE: single species which

increases pests and decreases

biodiversity, usually clearcut

• UNEVEN-AGED: trees are different

ages/sizes, usually different species.

Increases biodiversity, decreases pests &

erosion, trees are selectively cut

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TROPICAL FORESTS ARE BEING CLEARED

• Tropical forests occupy less than 10% of land

surface but contain half of all species.

• FAO estimates that 12.3 million ha are

deforested every yr, the equivalent of one

football field every second.

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CAUSES OF DEFORESTATION

• CONVERSION OF FOREST TO AGRICULTURE

Accounts for 2/3 of destruction in tropics

SLASH & BURN – aka: Milpa or Swidden

- cut/burn small areas & use for a few years

then let return to forest

- Slash & Burn can be sustainable if

populations are small and plots are left

alone for many years. Repeated cropping

over time leads to permanent damage.

- Usually multiple crops are grown at the

same time, harvested separately

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EFFECTS OF DEFORESTATION

• As forests are cleared, plant transpiration and

rainfall decrease.

• This leads to drought & erosion.

• Drought kills more vegetation.

• Fires become more numerous and extensive.

• More of the forest is then lost.

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FOREST PROTECTION

• Some places are being reforested (U.S. and China have had greatest gains.)

• About 12% of world’s forests are protected.

• With industrialization, countries become developed, deforestation decreases and forests are protected instead for other uses

• DEBT FOR NATURE SWAPS - conservation organizations/banks buy debt obligations, then offer to cancel the debt if the debtor country protects biologically important areas

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FORESTS HAVE COMPETING USES

• U.S. Forest Service managed for “multiple uses”

but many were conflicting e.g. bird watching and

dirt biking.

• OLD GROWTH FORESTS VS. LOGGING

Less than 10% of old growth forest remains in

U.S. and 80% of that is scheduled to be

logged.

Spotted owl vs. logging jobs

Compromise forest management plan allows

some logging, but protects some prime

habitat. May not be enough to save the salmon

and steelhead trout in northwestern rivers.

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OLD GROWTH FOREST • Temperate rainforest and the spotted owl.

• 2,000 owl pairs remain in the old growth forests

of the Pacific Northwest.

• Salmon & trout need pristine rivers to spawn

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HARVEST METHODS

• ALL HARVEST METHODS REQUIRE ROADS

Building roads to remove trees also allows

entry to forest by farmers, miners, hunters.

Lead to increased erosion, soil compaction, increased runoff of sediment into rivers

Sedimentation of rivers reduces biodiversity and decreases spawning

• CLEAR CUTTING – most popular with logging companies.

• Every tree in an area is cut regardless of size

• Increases erosion and decimates habitat

• Loss of recreational space

• Can be replanted or go through succession

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HARVEST METHODS

• SHELTERWOOD HARVESTING - mature trees are removed in a series of two or more cuts

• STRIP CUTTING - all the trees in a narrow corridor are harvested

• COPPICING – leaving stumps to regenerate (a few species can do this: oak, maple, ash)

• SEED TREE CUTTING – clear cutting but leaves a few trees to reproduce and drop seeds

• SELECTIVE CUTTING - only a small percentage of the mature trees are taken in each 10 to 20 year rotation (best method environmentally)

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HARVESTING – CLEAR CUTTING

Clear cutting (removal of all trees) in Washington’s

Gifford Pinchot National Forest.

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SELECTIVE HARVEST

COPPICING STRIP CUTTING

SHELTERWOOD HARVEST

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LOGGING ON PUBLIC LANDS?

• Some are calling for an end to all logging on

public lands.

Lands provide ECOLOGICAL SERVICES such

as clean water, rivers for fish, irrigation,

recreation. Worth $224 billion.

Federal government builds roads, manages

forests, fights fires and then sells the timber

to logging companies for less than their

costs. This is a subsidy for the logging

industry. Worth $4 billion.

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HISTORY OF US FORESTS

• 1897 – Forest Management Act – created

Forest Reserves for timber, mining & grazing

• 1905 – US Forestry Service forest reserves

are now national forests

• 1960 – Multiple Use Sustained Yield Act

replaced FMA. Requires forests to be

managed for lumber, recreation and wildlife

• USFS sells logging rights to timber

companies (highly subsidized)

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LOGGING ON PUBLIC LANDS?

• Timber companies claim logging produces

jobs, supports rural communities, keeps forests

healthy.

• Roads on public lands are another controversy.

Economists argue it opens up land for

motorized recreation and industrial uses.

Wildlife supporters see it as disruptive.

• Clinton protected 23.7 million ha of wilderness

from roads; Bush overturned this and ordered

expedited logging and mining. Obama

protected additional lands.... Trump?

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FIRE MANAGEMENT

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FIRE MANAGEMENT

• U.S. adopted a policy of aggressive fire control

in the 1930s.

• Recent studies indicate many biological

communities are fire-adapted and require

periodic burning for regeneration.

• Eliminating fires has caused woody debris to

accumulate over the years. Fires are now larger

and more severe.

• 40 million Americans now live in areas of high

wildfire risk.

• Collection of debris and small prescribed fires

can prevent large scale fires

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ECOSYSTEM MANAGEMENT

• Ecosystem management attempts to integrate

sustainable ecological, economic, and social

goals in a unified systems approach.

Managing across whole landscapes over ecological time

scales

Considering human needs and promoting sustainable

economic development

Maintaining biological diversity and ecosystem processes

Utilizing cooperative institutional arrangements

Generating meaningful stakeholder and public

involvement and facilitating collective decision making

Adapting management over time based on conscious

experimentation and routine monitoring.

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SUSTAINABLE FORESTRY

• Consumers can make better choices &

demand sustainable products

Home Depot – all wood is sustainably

raised and managed

Staples uses 30% recycled paper in many

of their products

• Forests can be used sustainably for other

products: nuts, fruits, mushrooms, latex

(rubber) and chicle (gum) that doesn’t

remove the trees

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GRASSLANDS

• Occupy about 1/4 of world’s land surface

(prairies, savannas, steppes, open woodlands)

• Frequently converted to cropland, urban areas, or other human use

• More threatened plants in rangelands than in any other American biome

• Can be used sustainably

PASTORALISTS move their animals to adjust to variations in rainfall and seasonal conditions. Reducing negative impact on land

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RANGELAND vs PASTURE

• RANGELANDS - have natural vegetation

managed by grazing, usually dry/poor for

agriculture

• PASTURES - have forage that is adapted for

livestock and managed, by seeding, mowing,

fertilization and irrigation.

• OVERGRAZING – results from too many

animals on the land for too long a period of

time. Plant roots die and soil compaction

occurs. Often overgrazed areas lead to

DESERTIFICATION

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OVERGRAZING

• 15% of US livestock feed on native grasslands.

• 90% of US grain crop (corn, alfalfa, oats) is used to feed livestock

• 75% of rangelands in the world are degraded; one-third of that is due to overgrazing.

• 55% of U.S. public lands are in poor condition due to overgrazing.

• Grazing fees charged for use of public lands are below market value and represent a hidden subsidy to ranchers.

• Ranchers claim that without a viable ranch economy, western lands would be further subdivided.

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NEW GRAZING METHODS

• ROTATIONAL GRAZING - encloses livestock in

a small area for a short time within a movable

electric fence to force them to eat vegetation

evenly and fertilize (manure) the area evenly.

• Can raise wild species such as bison or elk,

which forage more efficiently and fend off

predators, diseases and pests better than cattle

• Grazing multiple species together is beneficial

as each eats a different type or part of the plant.

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PARKS AND PRESERVES 12% OF EARTH’S LAND AREA IS PROTECTED.

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PARKS AND PRESERVES

• In the developing world, some parks exist only

on paper because they do not have money for

staff and management.

• Brazil has the largest protected area 19% of its

land. With more than 25% of the world’s

tropical forests, Brazil is especially important to

biodiversity.

• US has 16% of its land in “protected” status.

2/3 is sustainable use public lands

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PRESERVES NOT SAFE FROM

EXPLOITATION

• Excessive stock grazing in Greece

• Dam building in Columbia

• Oil drilling in the Amazon

• Mining & Logging – in Peru

• Coral reefs in Palau damaged by dynamite

fishing

• Eggs from endangered sea turtles are taken by

hunters in Indonesia

• Overuse by the public – Yellowstone, Zion,

Grand Canyon – very popular, but create issues

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OVERUSE OF NATIONAL PARKS IN U.S.

• Entertainment trumped nature protection.

• Fire suppression resulted in large fires.

• Traffic congestion

• Surrounding areas clear cut or mined

• Air pollution and smog

• Parks are profitable, but do not get to keep the money they generate.

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HISTORY OF US NATIONAL PARKS

• 1872 – President Grant established first

national park in the world – Yellowstone

• 1912 – US National Park System was created

• 1916 – National Park Service (Dept. of

Interior) was created. Stephen Mather was

first director.

• Currently there are 388 parks ranging from

national parks to historic sites, to memorials

and recreation areas

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WILDERNESS AREAS

• Areas of undeveloped land, undisturbed by

human activities that people can visit but can

not inhabit.

• 1964 – Wilderness Act – allows public areas to

be protected

WILDLIFE REFUGES

• 1901 – Theodore Roosevelt – started the

National Refuge System. 545 now exist.

• Managed for multiple use (camping, hiking,

fishing, hunting, mining, etc.)

• Arctic National Wildlife Refuge (ANWR) in

Alaska has been debated for oil drilling

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WORLD CONSERVATION STRATEGY

• Developed by the IUCN

Has 3 objectives:

Maintain essential ecological processes and

life support systems

Preserve genetic diversity essential to

improving cultivated plants and domestic

animals

Ensure that utilization of wild species and

ecosystems is sustainable.

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MARINE ECOSYSTEMS NEED PROTECTION

• Global fish stocks are becoming depleted and biologists are calling for protected areas where species can be sheltered.

20% of nearshore territory should be marine refuge area.

Refuge can replenish nearby areas.

• Coral reefs are threatened by rising temperatures, destructive fishing, coral mining and sediment runoff.

If conditions persist, all will be gone in 50 years.

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MARINE ECOSYSTEMS NEED PROTECTION

• Australia has the largest marine reserve in the

Great Barrier Reef.

• The U.S. 13 underwater parks such as the

Northwest Hawaiian Islands National Monument

and the Florida Keys

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CONSERVATION & ECONOMIC

DEVELOPMENT

• Struggle to save ecosystems cannot be divorced from struggle to meet human needs.

ECOTOURISM - tourism that is ecologically and socially sustainable

NATIVE PEOPLE have valuable ecological knowledge that can be used in ecosystem management.

UNESCO initiated “Man and Biosphere” program (MAB) calling for the establishment of BIOSPHERE RESERVES, protected areas divided into zones with different purposes.

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A MODEL BIOSPHERE RESERVE

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SIZE & DESIGN OF NATURE PRESERVES

• SLOSS debate - Is it

better to have Single

Large Or Several

Small reserves?

• Edge effects

• Corridors of natural

habitat essential

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SIZE & DESIGN OF NATURE PRESERVES

• One of the reasons that large preserves are

considered better than small reserves is that

they have more CORE HABITAT, area deep

within the interior of the habitat that has better

conditions for specialized species.

As human disturbance fragments the

ecosystem, habitat is broken into

increasingly isolated islands with less core

and more edge, supporting fewer species.

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LANDSCAPE ECOLOGY

• LANDSCAPE ECOLOGY - science that

examines the relationship between spatial

patterns and ecological processes such as

species movement or survival

Variables:

- Habitat size

- Shape

- Relative amount of core and edge

- Kinds of land cover surrounding habitat

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HOW SMALL CAN A HABITAT BE?