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HUMAN IMPACTS:
LAND USE
As the human
population grows, we
require more
resources to make the
things we need or
want.
More land is needed to
grow food, to build
roads and factories, and
even to provide parks
and recreation areas.
A. Habitat Loss
Definition: The loss of
natural areas and
habitats due to human
development.
A. Habitat Loss
Cause:
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.
A. Habitat Loss
Effect:
Loss of biodiversity:
increase predation
decreased dispersal
loss of ‘core’ habitat,
increase in ‘edge’
A. Habitat Loss
Solution:
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.
B. Habitat Fragmentation
Definition:
Habitat fragmentation disrupts
the ecosystem and the ability of
animals to move through natural
areas (for food or shelter).
B. Habitat Fragmentation
Cause:
Building of roads
Other development
Effect :
Loss of biodiversity
Solution:
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
Effect
Solution
When industries
or power plants
use water to cool
their machines,
they release
their warmed
water into a river
or lake.
Because warm
water does not
hold as much
dissolved oxygen
as cold water, the
oxygen level in
the lake drops
and species may
suffocate.
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
Cause:
Overuse use of powerful chemicals.
Leads to resistant pests!
C. Habitat Degradation
2. Chemicals
Effects:
Industrial processes add
detergents, heavy metals,
industrial chemicals to
their local environment.
Chemicals such as pesticides
& herbicides are used to
control agricultural pests.
These runoff into lakes and
rivers and contaminate the soil
and water.
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