Submitted to: Council for Agricultural Science and Technology Issue Paper
Publication Type: Review article
Publication Acceptance Date: 10/20/2002
Publication Date: 11/20/2002
Citation: KRUEGER, W., SANDERSON, M.A., CROPPER, J.B., MILLER-GOODMAN, M., PIEPER, R.D., SHAVER, P., TRILICA, M.J. ENVIRONMENTAL IMPACTS OF LIVESTOCK ON GRAZING LANDS. COUNCIL FOR AGRICULTURAL SCIENCE AND TECHNOLOGY ISSUE PAPER. No 13. 2002. Interpretive Summary: Grazing lands cover nearly 800 million acres in the U.S. Some view livestock use of public and private grazing lands as harmful. Key issues of concern include alteration of wildlife habitat and degradation of soil, water and environmental quality. Problems of today may relate to land use practices several decades ago and often need active management practices to orestore the health of the land. Grazing land managers make decisions daily that affect both the long term and short-term ability of the land to meet both ecological and business goals. Grazing management is the principal tool available to producers to prevent, reduce, or mitigate the effects of livestock on grazing lands. This includes controlling when, where, and how intensively livestock grazing on landscapes. Grazing land managers must learn to recognize and integrate ecological relationships to achieve short and long-term objectives. The availability of information and data are an important part of the decision making process. Producers should utilize knowledge about precipitation patterns and probabilities, plant growth cycles, forage inventory data to balance forage supply and demand. Livestock performance goals and objectives must be incorporated into a forage supply inventory to enable the decision-maker to develop management alternatives and make a decision regarding the management of the land.
Technical Abstract: Properly managed grazing lands provide several positive environmental benefits. The key to sustainability of grazing lands is perennial vegetative cover, which holds soil in place, filters water, and recycles nutrients. Significant changes in vegetation can have subtle to dramatic effects on the properties and functions of grazing land ecosystems. Grazing glands have significant capacity to sequester atmospheric carbon, serve as nutrient sink, and to help maintain biodiversity. Environmental impacts of livestock on grazing lands include manure and urine deposited directly into water or on land near surface waters, where leaching and surface runoff can transport nutrients to streams, ponds, and lakes. Inappropriate grazing practices may accelerate erosion and sediment transport to water, alter stream flow, and disrupt aquatic habitats. Mismanagement of grazing lands can impair the capacity of riparian vegetation to filter contaminants, to shade aquatic habitat, and to stabilize stream banks. Interactions among components of the grazing land ecosystem also affect environmental processes. Soils, water, and nutrients interact to determine plant productivity and the botanical makeup of grazing lands. Plants can affect the biogeochemistry of soils via the return of plant litter. Grazing animals interact with plants and soils, resulting in larger gradients in spatial and temporal variability and altering productivity, vegetative structure, and floral diversity. Complicating these factors is the variability in soils, plants, and weather across time and space in grazing land ecosystems. Disturbance of the ecosystem and rate of recovery from disturbance modify environmental impacts. Impacts can be managed by controlling when, where, and how intensively livestock graze on landscapes.