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