"overgrazing." A Dictionary of Plant Sciences. . Encyclopedia.com. (May 24, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/overgrazing
"overgrazing." A Dictionary of Plant Sciences. . Retrieved May 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/overgrazing
Overgrazing is one of the most critical environmental problems facing the western United States. Rangelands have been mismanaged for over a hundred years, mainly due to cattle grazing. In addition to consuming vegetation, cattle alter the ecosystem of rangeland by tramping, urination, defecation, and trashing. Degradation due to heavy livestock grazing continues to occur in many diverse and fragile ecosystems, including savanna , desert , meadow, and alpine communities.
Riparian lands, highly vegetated, narrow strips of land bordering rivers or other natural watercourses, make up only two percent of rangelands, but have the most diverse populations of vegetation and wildlife . Overgrazing has had a devastating effect on these areas. Cattle eat the seedlings of young trees, which has led to the elimination of some species , and this has reduced the species of birds in these areas and disrupted migratory patterns. Lack of new tree growth in riparian areas has also resulted in the drying up of stream beds and the loss of habitat for fish and amphibians. It has contributed to the problem of soil erosion , desertification and the greenhouse effect . Other rangeland ecosystems are facing similar disruption.
The Bureau of Land Management (BLM) part of the U. S. Department of the Interior is the largest landholder in the United States. They are responsible for 334 million acres of land which fall under multiple-use mandates. The BLM leases much of this public land to individuals for grazing purposes, charging ranchers approximately $1.35 per month to graze one cow and a calf. It has been estimated that the fair market value for such forage is $6.65, and the agency has come under attack for leasing grazing rights at extremely low rates. It has also been criticized for allowing abusive land management practices. Critics claim that those who utilize these public lands try to maximize profits by putting excessive numbers of livestock on the range, and they argue that almost half of the range areas in the United States are in dire need of conservation .
Environmentalists argue that it is possible to eliminate overgrazing and manage rangelands in a way that both preserves ecosystems and meets the needs of ranchers. They advocate above all the reduction of herds. They also suggest that cattle should not be allowed to roam at will and should be rotated among various pastures, so that all rangeland areas can receive back-to-back spring and summer rest.
Perhaps the main obstacle in conservation of rangelands is the lack of knowledge regarding their diverse ecosystems. Rangelands are regions where natural revegetation tends to be slow. Artificial attempts to introduce and establish plant growth have been frustrated by the fact that development is a long-term process in these environments as well as by other factors. Knowledge of the dynamics of competition , reaction, and stabilization of species is minimal. For over a century, rangers have tried to eliminate sagebrush, planting wheatgrass in its place. The solution has been short-lived because sagebrush usually prevails over wheatgrass in the natural succession of plants. To further compound the problem, overgrazing has depleted the perennial grasses that compete with sagebrush, and the plant has become even more prolific. A better understanding of the dynamic relationship between plants, animals, microorganisms , soil, and the climate is necessary to reestablish rangeland areas.
[Debra Glidden ]
Heitschmidt, R. K., ed. Grazing Management: An Ecological Perspective. Portland, OR: Timber Press, 1991.
Spedding, C. R. W. Grassland Ecology. London: Oxford University Press, 1971.
Senft, R., et al. "Large Herbivore Foraging and Ecological Hierarchies; Landscape Ecology Can Enhance Traditional Foraging Theory." Bioscience 37 (December 1987): 789–95.
Strickland, R. "Taking the Bull by the Horns: Conservationists Have Been Wrangling Politely With Land Managers For Years—But Have Failed to Halt Overgrazing Throughout the West." Sierra 75 (September-October 1990): 46–48.
"Overgrazing." Environmental Encyclopedia. . Encyclopedia.com. (May 24, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/overgrazing
"Overgrazing." Environmental Encyclopedia. . Retrieved May 24, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/overgrazing