HUMAN IMPACTS: LAND USE
More land is needed to grow food, to build roads and factories, and even to provide parks and recreation areas.
As the human population grows, we require more resources to make the things we need or want.
Definition: The loss of natural areas and habitats due to human
development.
A. Habitat Loss
A. Habitat Loss
As the human population increases, our use of land decreases the space and resources available for other species.
Deforestation is the burning or cutting of forests for human uses. This results in widespread habitat destruction.
Cause:
Effect:
Loss of biodiversity:
increase predationdecreased dispersalloss of ‘core’ habitat, increase in ‘edge’
A. Habitat Loss
Solution:
A. Habitat Loss
Protection of wild land
Wise land use
B. Habitat Fragmentation
Definition:
Sectioning or breaking up a natural landscape into smaller pieces. This reduces habitat sizes and isolates small sections of habitat.
Habitat fragmentation disrupts the ecosystem and the ability of animals to move through natural areas (for food or shelter).
B. Habitat Fragmentation
Definition:
Cause: Effect : Solution:
B. Habitat Fragmentation
Building of roads
Other development
Loss of biodiversity Better land planning.
Habitat corridors.
C. Habitat Degradation
Definition: A decrease in the quality of habitats due to poor land-use.
C. Habitat Degradation
1. Thermal (heat) pollution:
Cause
When industries or power plants use water to cool their machines, they release their warmed water into a river or lake.
Effect
Because warm water does not hold as much dissolved oxygen as cold water, the oxygen level in the lake drops and species may suffocate.
Solution
Regulate emissions of heat.
C. Habitat Degradation
2. Sewage and fertilizers:
Cause:
Sewage, animal wastes, and agricultural fertilizers add extra nutrients to streams, lakes, and ponds.
C. Habitat Degradation
2. Sewage and fertilizers:
Effect:
Too many nutrients cause algal blooms (explosive growth of algae) on the surface of the water (called eutrophication).
Less sunlight penetrates, organisms die, the numbers of decomposers increase which use oxygen (for respiration), less oxygen is available for other
organisms (fish die too).
eutrophication is water pollution caused by excessive plant nutrients.
C. Habitat Degradation
2. Sewage and fertilizers:
Solution:
Living “buffers” along streams
Better land planning
C. Habitat Degradation
2. Chemicals
Overuse use of powerful chemicals.
Leads to resistant pests!
Cause:
C. Habitat Degradation
2. Chemicals
Effects:
Chemicals such as pesticides & herbicides are used to control agricultural pests. These runoff into lakes and rivers and contaminate the soil and water.
Industrial processes add detergents, heavy metals, industrial chemicals to their local environment.
C. Habitat Degradation
2. Chemicals
Effects:
Biomagnification is the increase in the concentration of a substance (poison) in living tissue as you move up the food chain. DDT in the food chain was responsible for a decline of bald eagle populations.
C. Habitat Degradation
2. Chemicals
Solutions:
Ban DDT (1972)
Regulate emissions
Switch to biological control