land use: forests and grasslands. world land use
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World Forests Why important?
Provide habitats and food for wildlife Control water runoff Regulate the climate Purify the air
Amount of Forests Left About 3.8 billion ha (1 ha= 10,000 square
meters) Covers around 29% of earth’s land surface
Closed Canopy: Tree crowns are spread over 20% or more of the ground (80% of total forests)
Open Canopy: Tree crowns are spread less than 20% of the ground (20% of total forests)
Old Growth Forests Old Growth Forest: Forests free from
disturbance long enough to have mature trees, physical conditions, species diversity, and other characteristics of equilibrium ecosystems
In danger due to increase human activity in forests
Less than 50% of forests today retain old growth features
Forest Products Industrial timber has become the major
use of wood in the modern word 3.7 billion metric tons sold per year
Fuelwood represents the other half of wood harvested by humans Supplies the main source of heating and
cooking to third world countries
Forest Management Forest Management involves planning
for sustainable harvests, with particular attention paid to forest regeneration
25% of world’s forests are scientifically managed for wood production
Monoculture Forestry Saves money and labor leading to high profits Promotes the spread of disease and pest
infestations
Tropical Forests Rich biodiversity Contains at least ½ of the earth’s plant,
animal, and microbial species
Tropical Forest Disappearance Between 1990 and 2000, 9-12 million ha
of tropical forest was lost Tropical forest cover decreases at around
0.8% each year Most tropical forests are lost in Africa Fueled by Cattle ranching, fruit
plantations, mining, and illegal logging
Alternatives Milpa/Swidden Agriculture
“Slash and Burn” Prevents erosion, infestation, and tree loss Form of Mixed Perennial Polyculture
Forest Protection Tropical forest reservations are being set
up worldwide Debt-for-Nature Swaps
People in developed countries can aid the preservation of forests
Hope is to reduce debt and preserve wildlife at the same time
Temperate Forests Like tropical forests, temperate forests are
also facing danger because of deforestation
Harvesting Methods Most popular method in U.S. and Canada
is clear-cutting An alternative to this is Selective Cutting
Fire Management Many ecosystems are reliant upon periodic
fires for regeneration Trying to prevent fires in the these
ecosystems will slow its growth, and will also cause bigger fires by building up debris
U.S. government has stopped trying to fight some fires, and are letting them naturally burn Salvage Logging
Grasslands 2nd to forests in amount used and altered
by humans Grasslands have been reduced by 1/3
since the spread of agriculture Pasture: enclosed or managed grasslands Rangeland: unfenced, natural prairie and
open woodland
Management Traditional ranchers can avoid overgrazing
or overusing the land Currently, management is allowing
overgrazing to occur Desertification
Range Conditions in the U.S. Most of livestock do not graze on public
rangelands Lack of enforcement on rangelands led to
overgrazing 55% of U.S. rangelands are in “poor to very
poor” conditions
Rotational Grazing Rotational Grazing simulates the actual
nature of wild grazing animals More healthy for the rangeland Some U.S. rangelands now require
rotational grazing
Land Ownership In most countries, most of the land is
owned by a small percentage of the people Has causes political and social unrest in some
countries Land Reform is an attempt to distribute
land to a greater amount of people May improve environmental conditions
Indigenous Land Rights Use 25% of land on earth Indigenous people often take better care
of their land than modern societies do Indigenous people often have their natural
resources taken away by modern societies
HALFTIME QUESTIONS!!!!!!!!!! What is the difference between a pasture and a rangeland? Name some advantages and disadvantages to selective
cutting Describe the “slash and burn” process Which countries are the largest producers of industrial
timber? What is fuel wood? Which continent experiences the most forest lost per year? What are some important roles that forests play in the
environment? What are some problems with monoculture forestry? Why is trying to prevent forest fires sometimes harmful to
some ecosystems? BONUS: What is one ha equal to in meters?
History of Parks In ancient times, parks were for only the
rich and powerful Public Parks were created in the 1800’s First National Park: Yellowstone National
ParkNational Parks have now spread all over the
world
National Parks One or more ecosystems that are not
altered by human activity Sites have scientific, educational, and
recreational value Humans can enter only for scientific,
educational, and recreational, and must not disturb the nature
Parks are protected by the national government
Wilderness Areas and Wildlife Refuges Wilderness: An area of undeveloped land
affected primarily by the forces of nature; an area where human are visitors and do not remain
Environmentalists push for more wilderness areas, industrialists want less wilderness
Wildlife Refuges Originally sanctuaries for wildlife Now 550 National Refuges in U.S. Now hunting is allowed Other damaging human activities are also
allowed
Global Nature Preservation World Conservation Strategy: A proposal for
maintaining essential ecological processes, preserving genetic diversity, and ensuring that utilization of species and ecosystems is suitable
4% of earth’s land designated as parks, refuges, and reserves
Europe has highest amount of protected sites Pacific has least amount of sites Amount of actual protection in these areas varies
Marine Preservation Over harvesting is depleting the oceans or
resources Ecosystems like coral reefs are being
destroyed at a rapid rate Scientists have called for increased
amounts of marine refuges Marine refuges shown to be very effective
Landscape Ecology Landscape Ecology: The study of the
reciprocal effects of spatial pattern on ecological processes. A study in which the landscape history shapes the features of the land and the organisms that inhabit it as well as our reaction to, and interpretation of, the land.
Considers humans an important part of most landscapes
Patchiness Ecosystems often have patches or certain
types of biotic and abiotic factors Patches shift with time Boundaries of these patches are important
Restoration Ecology Seeks to repair or reconstruct ecosystems
damaged or altered by humans Different degrees of restoration
Restoration Rehabilitation Remediation Reclamation Re-creation
Methods of Restoration Removing foreign organisms Planting organisms that original inhabited
the area Bringing back animals that originally
inhabited the area Letting nature heal itself
Preserving Wetlands 1990’s: Laws passed punishing any who
drain, fill, or damage wetlands with pollutants
Destruction of wetlands has greatly decreased
2001: Laws were then changed so that only around 20% of wetlands were protected
Wetland Migration: creating new wetlands to make up for those lost
Floodplains Floodplains are Low lands along
riverbanks, lakes, and coastlines that are subjected to periodic inundation.
Human have begun developing on floodplains
Has caused disruption in the ecosystem
Ecosystem Management Integration of ecological, political, and
social goals to try to solve the environmental problems
Goals: All levels of the environment must be managed Stop political boundaries Routine data collection Adaptive management Humans in nature Organizational change Values
Works Cited Cunningham, William P., Mary Ann Cunningham,
and Barbara Woodworth Saigo. Environmental Science a Global Concern. 9th ed. New York: McGraw, 2007. Print.
http://auth.mhhe.com/biosci/pae/environmentalscience/olc_linkedcontent/cunningham06es/cs6_15.htm
http://auth.mhhe.com/biosci/pae/environmentalscience/olc_linkedcontent/cunningham06es/cs6_05.htm
http://www.fws.gov/Refuges/