Evolutionary implications for grazing management systems
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Authors: K. A. Platou, and P. T. Tueller
Date: 1985
Journal: Rangelands
Volume: 7
Number: 2
Pages: 57-61
Summary of Methods: Herd effect on the Great Plains creates the attributes of low selectivity, heavy grazing pressure, trampling, dunging and urinating in a concentrated area. This activity is important in the cycling of nutrients in the soil and in the dissemination, germination, and establishment of seeds, particularly in high use areas. The requirement for forage quantity ensures that herds do not remain in any one area for very long and that they do not return to the same area until the forage is adequate to meet the energy requirements of grazing. The essence of this system is high-intensity, short-duration grazing. On the shrub-steppe of the Great Basin, animals are more dispersed. Plants growing in the Great Basin cannot withstand repeated heavy grazing pressure in part because of the shorter growing season; however, with the low animal density, the same individual plant is less likely to be grazed at the same time each year, allowing for seed set and accumulation of carbohydrate storage in some years. The longer rest period between grazing periods for these lower producers is the key feature of this natural system. A high-intensity, short-duration grazing method on the shrub-steppe which did not coevolve with a generalist herbivore would not work. The required recovery period is too long to accommodate repeated grazing cycles per season; only a full season rest every few years allows for maintenance of bunchgrasses. The rest-rotation system has met with only limited success on warm-season prairie grass ranges. The authors note that it ought to be recognized that the two most highly touted grazing management systems in the U.S. are closely related to natural systems that have evolved within the framework of specified environmental biotic and abiotic variables. In the future, studies should be directed toward greater understanding of various natural grazing systems.
Article Summary / Main Points: None
Vegetation Types:
MLRA Ecoregions:
Agrovoc Control Words: Riparian zones Rangelands Wildlife
Article Review Type: Peer Reviewed
Article Type: Scientific Synthesis
Keywords: grazing management systems, great basin, great plains, ecosystem-herbivore interactions, shrub steppe, mixed grass prairie, shortgrass prairie
Annotation: None
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