Environmental Biology

1. Potential Threats to Rangelands

2. Threats include:

3. Overgrazing
Invasive
plants
Human
Population
Soil Erosion
and
Desertification
Wildland Fire
& Climate
Change
Complex
Land Tenure
Other Factors

4. 1. Overgrazing
Biggest Problem
Carrying Capacity- Cannot support grazing
over a certain limit.
Overgrazing- in combination with:
Poor land
use
practices
and
Absence of
scientific
grazing
system
Sharp
decline of
many
grasses
Inferior
vegetation
invasion

5. 2. Invasive Plants
Plants that interfere with the growth
of desirable plants.
Abundance of native species- Reduced
Monoculture-where only one species
dominates.
Water infiltration- Reduced
Altering soil characteristics
Altering fire intensity and
frequency
Examples: Cheatgrass, leafy spurge,
spotted knapweed, and salt cedar

6. 3. Human Population
Demands for:
Food
commodities
and
Energy
Woody
vegetation
Overexploited
For Fuel
To meet food
requirements:
Rangelands
converted to
agriculture
Results in:
Soil Erosion
and
Land
Degradation

7. 4. Soil Erosion and Desertification
Permanent loss of:
Productive rangelands
Loss of Biodiversity
Caused by:
Overgrazing
Excessive removal of vegetation

8. 5. Climate Change
Rise in temperature = increase
rate of evapo-transpiration
Leading to
Loss of
moisture
Heat stress on Livestock
Incidence of pests and diseases-
reduced livestock productivity
Socio-economic loss

9. 6. Wildlife Fire
Role in maintaining rangeland
Depends largely on:
Growth form
Plant adaptations, and
Season of burning

10. Continued…
In Hot, dry, summer
months is the most
harmful- High
Intensity Fires
Late summer and fall
burns are the least
harmful- Increased
Moisture and Low
Temperatures

11. 7. Complex Land Tenure
Community owned and
Used as common property resource
Maximum benefits
Ethnic groups- Raising Livestock for generations
Ownership and Herders Conflict

12. 8. Fragmentation of Rangelands
Increased Human activity and
Construction of roads and
buildings
Rural subdivision and fragmentation
lead to
Increased weeds
Loss of biodiversity, and
Degradation of pasture lands.

13. Continued…
Example: Houses built on wildlife
winter habitat inhibits animals from
moving down.
Rare and sensitive species-
Limited to a Specific Habitat
Find themselves in danger

14. 9. Lack of Institutional Setup
Forest Departments
Protection and development of forests rather than rangelands
Shortage of:
Technical expertise and
Financial resources

15. References
http://www.pfi.gov.pk/Ranglandpolicy.html
http://www.forestrynepal.org/notes/biodiversity/
management/habitat/rangeland
Brown, J.R., R.R. Blank. G.R. McPherson, and K.W. Tate. 2005.
Rangelands a global change. Published by the Society for Range
Management. Available online at:
http://www.rangelands.org/pdf/Global_Issue_Paper.pdf.