Seasonal Patterns of Forage Availability in the Fescue Grasslands Under Contrasting Grazing Histories |
| |
| Authors: | Edward Bork Walter Willms Steven Tannas Mike Alexander |
| |
| Institution: | 1. Professor, Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada;2. Research Scientist, Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada;3. Graduate Student, Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada;4. Provincial Rangeland Specialist, Alberta Sustainable Resource Development, Lands Division, Pincher Creek, AB, T0K 1W0 Canada;1. Ecologist, USDA-ARS, Eastern Oregon Agricultural Research Center, Burns, OR 67826, USA;2. Assistant Professor, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84642, USA;3. Professor, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84642, USA;4. Associate Professor, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84642, USA;5. Professor, Department of Horticulture, Cornell University, Geneva, NY 14456, USA;1. Soil Scientist, US Department of Agriculture–Agricultural Research Service, Great Basin Rangelands Research Unit, Reno, NV 89512, USA;2. Research Technician, US Department of Agriculture–Agricultural Research Service, Great Basin Rangelands Research Unit, Reno, NV 89512, USA;1. Research geneticists, US Department of Agriculture–Agricultural Research Service, Forage and Range Research Laboratory, Utah State University, Logan, UT 84322, USA;2. Beaver County Extension Agent, Utah State University, Beaver, UT 84713, USA;1. Fish and Wildlife Biologist, US Fish and Wildlife Service, Bishop, CA 93514, USA;2. Professor, Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA;3. Assistant Professor, Department of Forest, Rangeland, and Fire Sciences, University of Idaho, Moscow, ID 83844, USA;4. Professor Emeritus, Department of Animal and Range Science, Oregon State University, Corvallis, OR 97331, USA;5. Range Scientist, Retired, US Department of Agriculture (USDA) Forest Service, Rocky Mountain Research Station, Reno, NV 89509, USA;6. Research Ecologist, US Department of Agriculture (USDA) Forest Service, Rocky Mountain Research Station, Reno, NV 89509, USA;7. Associate Professor, Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61801, USA;8. Assistant Professor, Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61801, USA;9. Associate Research Professor, Department of Statistics, Brigham Young University, Provo, UT 84602, USA |
| |
| Abstract: | Grazing by large herbivores has been shown to condition vegetation in a manner that improves grassland quality for subsequent herbivory. Fescue grasslands evolved with disturbance from fire and winter grazing by bison but are now grazed primarily by cattle during summer. We examined the effect of long-term summer grazing on the seasonal forage production and quality of fescue grasslands in an examination of the hypothesis that long-term grazing had conditioned fescue grasslands to benefit livestock. This hypothesis was examined by comparing, between grazed and ungrazed plots, the biomass and composition of herbage components, concentrations of nitrogen (N) and acid detergent fiber (ADF) therein, and the ability of major plant types to maintain their biomass and quality throughout the growing season. The study was conducted in southern Alberta at five sites that had long-term exclosures (20+ yr) on grasslands that had been moderately grazed. Grazing had no effect on the N concentration of associated grasses, but grasses had lower N concentration than forbs. Concentrations of ADF followed a reciprocal trend to N. Grazing increased the mass of forbs from about 10% to 20% as a proportion of total biomass, which in turn, was not affected by grazing history. However, this grazing-induced shift to a higher quality vegetation type was not sufficient to affect total mass of N or total digestible nutrients at the community level. Rather than changes in current growth and quality, the predominant effect of summer grazing was in reducing litter mass, which also had the potential for affecting forage production and selection by herbivores. Finally, grazing reduced the relative contribution of rough fescue to total biomass by about 30%, and despite no significant effect on the potential to support summer grazing, this change could reduce the quality of these grasslands for winter grazing. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
