32 terms

Chapter 6

Sustaining Biodiversity: The Ecosystem Approach

Terms in this set (...)

Forests vary in their make-up, age and origins
Old-growth or primary forests, second-growth forests, tree plantation, tree farm or commercial forests
Old growth or Primary Forest
attained great age without significant disturbance, 36% of world's forests are old growth
Second-growth forests
forest that has regrown after major disturbance (60%)
Tree-plantaion, tree farm, or commercial forest
privately owned and managed... 4% of the world's forests, may supply most of the industrial wood in the future
Monoculture tree plantations
planting of one species of a tree.. takes 25 years to fully grow
Forests provide important economic and ecological services
* support energy flow and chemical cycling
* reduce soil erosion
* absorb and release water
* purify water and air
* influence local and regional climate
* store atmospheric carbon
* habitats
* wood for fuel
* lumber
* pulp to make paper
* livestock grazing
* recreation
* employment
Unsustainable Logging
logging in an area where there aren't always enough trees to be cut / enough left after... can't continue at a steady rate and the trees will be all gone.
*MAJOR THREAT to forest ecosystems
* increased erosion
* sediment runoff into waterways
* habitat fragmentation
* loss of biodiversity
Invasion by
nonnative pests, disease, wildlife species
Major tree harvesting methods
selective cutting (cutting out trees that are either mature or defective, clear-cutting (most or all trees in an area are uniformly cut down) strip cutting (cutting down a strip of trees, selective section)
Natural Capital Degradation when it comes to forests
building roads into previously inaccessible forests
cutting down trees.. we have cut down almost half of the world's forests. tropical forests in Latin America, Indonesia, and Africa. Boreal forests in Alaska, Canada, Scandinavia, and Russia
Case Study: Many cleared forests in the US have grown back
forests of the eastern US decimated between 1620 and 1920 and have grown back naturally through secondary ecological succession in the eastern states, biologically simplified tree plantations reduce biodiversity
Tropical forests are disappearing rapidly
majority of loss since 1950 in Africa, Southeast Asia, South America, 98% will be gone by 2022, role of deforestation in species' extinction, secondary forest can grow back in 15-20 years
Causes of tropical deforestation are varied and complex
population growth, poverty of subsistence farmers, ranching, lumber, plantation farms: palm oil
begins with building roads, many forests burned, can tilt tropical forest to tropical savanna
Basic and Direct causes of destruction of tropical forests
* not valuing ecological services
*crop and timber exports
*government policies
*population growth

* roads
* settler farming
* cash crops
* cattle ranching
* logging
* tree plantations
How should we manage and sustain forests?
emphasize the economic value of their ecological services, remove government subsidies that hasten their destruction, protect old-growth forests, harvest trees no faster than they are replenished, plant trees
Solutions to more sustainable forestry
* identify and protect forest areas high in biodiversity
* rely more on selective cutting and strip cutting
* stop clear cutting on steep slopes
* stop logging in old-growth forests
* reduce road building in uncut forest areas
* put tree plantations only on deforested and degraded land
* certify timber grown by sustainable methods
* include ecological serves of forests in estimates of their economic value
Green Belt Movement 1977
* self-help group of women in Kenya
* success of tree planting
* 50,000 members planted 40 million trees
* women are paid for each tree that survives
* slows soil erosion
* shade and beauty
* combats global warming
* noble peace prize in 2004
Governments and Individuals Can Act to Reduce Tropical Deforestation
Reduce fuelwood demand
Practice small-scale sustainable agriculture and forestry in tropical forest
Debt-for-nature swaps
Conservation concessions
Use gentler logging methods
Buy certified lumber and wood products
National parks face many environmental threats
*1100 major national parks worldwide
*parks in developing countries have the greatest biodiversity and only 1% is protected against illegal poaching and logging and mining
Case Study: Stress on US Public Parks
* 58 major national parks in the US
* biggest issue is their popularity
- noise
- congestion
- pollution
- damage or destruction to vegetation and wildlife
* damage from nonnative species (boars, mountain goats, introduced plants, insects, worms)
* native species are sometimes killed or removed
* threatened islands of biodiversity (air-pollution)
* need billions in trail and infrastructure repairs
Solutions for National Parks
* integrate plans for managing parks and nearby federal lands
* add new parkland near threatened parks
* buy private land inside parks
* locate visitor parking outside parks and provide shuttle buses for people touring heavily used parks
* increase federal funds for park maintenance and repairs
* raise entry fees for visitors and use resulting funds for park management and maintenance
* seek private donations for park maintenance
* limit the number of visitors in crowded park areas
* increase the number of park rangers and their pay
* encourage volunteers to give visitor lectures and tours
Reintroducing the gray wolf to yellowstone national park
* grey wolves are keystone species
* in 1995 they were reintroduced, 116 wolves in park by 2009
* prey on eld and push them to a higher elevation
- regrowth of aspen, cottonwoods, and willows
- more beaver dams, more wetlands, more aspens
* reduced the number of coyotes
- fewer attacks on cattle
- more small mammals
Nature reserves occupy only a small part of the earth's land
* currently less than 13% but conservationists' goal is to protect 20%
* cooperation between government and private groups and concerned individuals
* nature conservancy
* land trust groups
Solution: A model biosphere
from center to outer: core area, research station, buffer zone 1, buffer zone 2, visitor education center, human settlements
Case Study: Costa Rica - A global conservation leader
* 1963-1983: cleared much of the forest
* 1986-2006: forests grew from 26% to 51%
- goal was to get the net carbon dioxide emissions to zero by 2021
* 1/4 of land in nature reserves and natural parks - global leader
* has national parks and buffer zones
* earns $1 billion per year in tourism
Protecting wilderness is an important way to preserve biodiversity
wilderness = land officially designated as having no serious disturbance from human actives
* wilderness act of 1964
* controversial...
Controversy over the wilderness act
* act protected undeveloped lands
* 2% of lower 48 protected, mostly in west
* 2009 = 2 million more acres get wilderness protection
* 50% increase in length of wild and scenic rivers
What is the ecosystem approach to sustaining biodiversity?
* identifying and protecting severely threatened areas (biodiversity hotspot), restoring damaged ecosystems, and sharing as much of the earth's land as possible with other species
4 point strategy to protect ecosystems
1. map global ecosystems; identify species
2. locate and protect most endangered ecosystems and species
3. restore degraded ecosystems
4. development must be biodiversity-friendly
* are new laws needed?
Protecting global biodiversity hot spots in an urgent priority
* 34 biodiversity hotspots are rich in plant species
* 2% of the earth's surface, but 50% of flowing plant species and 42% of terrestrial vertebrates
Three Big Ideas
1. The economic values of the important ecological services provided by the world's ecosystems are far greater than the value of raw materials obtained from those systems.

2. Terrestrial and aquatic ecosystems are being severely degraded by human activities that lead to habitat disruption and loss of biodiversity.

3. We can help to sustain the world's biodiversity by mapping it, protecting biodiversity hotspots, creating large terrestrial and aquatic reserves, and carrying out ecological restoration of degraded terrestrial and aquatic ecosystems.