Sustaining Ecosystems

Chapter 10

Big Bad Wolf

• Listed as endangered on lower 48 states due to hunting, poisoning, trapping by hunters and ranchers

• Now its role is evident – culled bison, elk, etc., kept down coyote population, provide meat for scavengers

• Reintroducing wolves has had positive effects saving vegetation the herds would strip clean

Collapse in Yellowstone?

• Natural regulation – hands off approach• Elk have flourished from 3,000 to 20,000• Trees not growing b/c elk eat shoots• No trees hurts beavers• Fewer beavers less dams• Less dams, less sediment build up and meadow

production• Yellowstone may allow elk to be hunted again

Ecotourism

• The Belize river is an example of successful ecotourism

• Farmers allow strips of jungle to connect preserves allowing monkeys a need corridor

• Visitors come to see the monkeys

• Locals make money supplying visitors with room and board

Public lands in the US

• 42% public land – most of any nation, but most is in Alaska (73%)

• Classified into 3 areas– Multiple use lands– Moderately restricted use lands– Restricted use lands

Multiple use lands

• National forest system managed by the US forest service

• To be managed under sustainable yield and multiple use principle (except 15% wilderness)

• Timber harvests, grazing, recreation, wildlife conservation, mining, OHVs, hunting, oil extraction, farming, and fishing

Multiple use lands

• National resource lands

• Managed by BLM (bureau of land management) in western US

• Emphasis on providing domestic supply of energy and strategic minerals

• Also preserves rangeland for grazing

Moderately restricted-use lands• National wildlife refuges (508)• Managed by US fish and wildlife• 24% is designated wilderness (no vehicles,

mining, etc.)• Most protect habitats for game animals• Some areas allow oil extraction, mining,

logging, hunting, grazing and military activities if DoI approve

Restricted use lands

• National park system (375)• Managed by nation park service• Goal is to preserve scenic and historic

heritage, protect habitats, provide recreation• About 49% designated wilderness• Cars only on paved roads, in nation

recreation areas some mining, oil, hunting is allowed

Restricted use lands

• National wilderness preservation system (630)

• Managed by NPS, NFS, FWS, and BLM

• Only open to hiking, camping, etc.

• Banned – roads, logging, grazing, mining, buildings, commerce, etc.

Preservation vs conservation• Preservation – keep habitats intact, primary

goal is maintaining biodiversity and sustainability

• Conservation – use land for economic gain including mining, logging, grazing

• They try to be sustainable, but have not succeeded so far

Rangelands

• Grasslands suitable for cattle

• 3 billion ruminants (can digest cellulose) mostly cattle, sheep and goats

• Grasses grow from base of plant (potentially renewable if base is left intact)

• Rangelands currently being degraded by desertification

Overgrazing

• Leads to soil compaction

• Allows invasive species into rangeland

• Lowers water holding capacity of soil

• Exposes soil to erosion

• Major cause of desertification in arid and semi-arid lands

Riparian zones

• Thin strips of lush vegetation along streams

• Prevents flooding by storing and releasing water slowly

• Provides habitat (food, water, shade, nests)

• 65-75% of wildlife in western US depends on riparian zones

• Cattle tend to trample riparian zones

Types of forest

• Tropical, temperate, and polar

• identified by climate

• about half the world’s forests are in the tropics

• more than 60% of the remaining forests reside in only 7 countries: US, Brazil, Canada, Russia, China, Indonesia, and Congo (Zaire)

Emergent

Canopy

Understory

Floor

Subsoil

Birds, invertebrates,bats

Birds, reptiles,amphibians,lichens, mosses

Shade-tolerant plants, birds, squirrels,lizards, chipmunks

Rotting debris,worms, insects,bacteria

Nematodes,microrganisms

Bole

Snag

Fig. 23.6, p. 592

Losing forests

• At least 2 million sq. kilometers of forest lost between 1990 and 1995 (three times the size of Texas)

• Each year 160,000 sq. km lost

• As populations increase, rate of loss increases

• At least 107 countries reported a net loss of forest between 1990 and 1995

Virgin forests, 1620

Fig. 23.13a, p. 600

Virgin forests, 1998

Fig. 23.13b, p. 600

Annual Deforestation Rates

More than 1% loss

0.5–1% loss

0–0.5 loss

Stable or increased forest

No data

Fig. 23.8, p. 594

Types of forest succession

• Old growth forest - rich biodiversity, untouched for several hundred years, large number of niches, large number of standing dead trees (snags), fertile soil

• US lost 95-98% of its old growth forests

Types of forest succession

• Second growth forest - trees resulting from succession after clear cut

• about 40% tropics second growth

• most of US is second growth

• second growth are undisturbed long enough to reach a climax community, but lack diversity, typically tree farms

Economic importance

• Worth $300 billion a year• each year US consumes enough wood to fill 2

million boxcars• Worldwide 55% of the wood is used for fuel• one third of the wood is used as lumber• since 1950 the demand for wood has doubled

and paper increased five fold• demand is expected to double again by 2010

Ecological importance

• Forest slow flow of water out of a watershed• Allows aquifer to recharge/reduces runoff

and erosion• influence climate - transpiration increases

air moisture and thus more rain/cooler in that area (tropics)

• remove CO2• buffer against noise, air pollutants

What’s a tree worth?

• One tree is worth about $196,250

• This is the amount of money in services the tree provides to the planet

• Air filtration, oxygen production, soil fertility, erosion control, water recycling, humidity control, habitats

• A tree is typically sold for $590

Emergent

Canopy

Understory

Floor

Subsoil

Birds, invertebrates,bats

Birds, reptiles,amphibians,lichens, mosses

Shade-tolerant plants, birds, squirrels,lizards, chipmunks

Rotting debris,worms, insects,bacteria

Nematodes,microrganisms

Bole

Snag

Fig. 23.6, p. 592

Tree products

• There are over 20 categories of products from trees– lumber– charcoal– drugs– oils– dyes– nuts/fruits

Norther spotted owl

• What is the importance of the spotted owl?

• By being listed as threatened by fish and wildlife, its habitat, old growth douglas fir, must be protected

• Logging is opposed to this because of the large loss of revenue

Canada’s link to forestry

• Largest exporter of timber $30 billion

• 10% of jobs directly related

• lost 60% old growth

• 90% involves clear cutting

• one half of the remaining temperate forest in Canada, scheduled for clear cut

• losing an acre every 12 seconds

Tropical forest loss

• Being cut at an alarming rate

• rate is increasing with population growth and economic demand

• South America most severe, but rate of loss is higher in Southeast Asia and Central America

Madagascar

• Fourth largest island (off east side of Africa)• 160,000 species unique to the island• slash and burn has devoured habitat• cut forests allowed massive erosion• most eroded country in the world• will lose at least half its biodiversity• trying to reform using reforestation, but

population scheduled to double (2025)

MADAGASCAR

INDIANOCEAN

Existing rain forest

Former rain forest

Southern spiny desert

Western tropical deciduous forest

Fig. 23.17, p. 607

How bad is it?

• If current trends in rain forest degradation remain…

• estimated 20% forest species gone by 2022

• 50% by 2042

• worst extinction in 65 million years

• way to go humans!!

Sustainable forestry

• By harvesting nuts, berries, resins, dyes, oils, etc. over the course of 50 years would yield greater profit than would harvesting the lumber

• But it is long term gain vs. being able to harvest trees now and move to a new area (more profit b/c you cut more trees)

Selective CuttingFig. 23.11a, p. 596

Shelterwood Cutting

Cut 1

Cut 2

Fig. 23.11b, p. 596

Seed-Tee CuttingFig. 23.11c, p. 596

Clear-Cutting

Fig. 23.11d, p. 596

Strip Cutting

Uncut Cut Cut Cut Uncut

6–10 years ago

3–5 years ago 1 year ago

Fig. 23.11e, p. 596

Cause of tropical deforestation• Population growth, poverty, govt. policy

• landless poor use forest for food/money

• govt. makes timber cheap to boost economy

• finance roads, mines, logging, oil, and dams

• creates needs for small shops, lodging

• business moves in, need for housing

• half of deforestation from inexperienced farmers trying to farm new land

How to help biodiversity

• Preserve more land in the world 6% now should be 10% minimum

• Reserves should be at least 3,900 sq miles• Set up biosphere reserves (5 or more)

– Core (no human activity)– Buffer zone (research activity)– Buffer zone 2 (limited human

activity/tourism)• Create corridors between reserves

Further protection

• National Wild and scenic rivers system– River cannot be altered or developed

• National Trails System– Not enough funding or management

to successfully maintain currently

Best defense

• Educate yourself• Educate others• Support charities like Sierra Club, Nature

Conservancy, World Wildlife Fund, Audubon Society, etc.

• Get out and enjoy the outdoors while helping to protect it

• Remember, it’s your world, don’t let others ruin it!

Good Job Everyone!

• No go out and hug a tree!!