Ungulate herbivory on Utah aspen: Assessment of long-term exclosures
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Authors: C. E. Kay, and D. L. Bartos
Date: 2000
Journal: Journal of Range Management
Volume: 53
Number: 2
Pages: 145-153
Summary of Methods: The role of livestock grazing and big-game browsing in the decline of aspen (Populus tremuloides), in the Intermountain West, has long been questioned. Kay and Bartos measured all known aspen exclosures on the Dixie and Fishlike National Forests in south-central Utah to determine aspen stem dynamics, successional status, and understory species composition. Aspen within all total-exclusion plots successfully regenerated and developed multi-aged stems without the influence of fire or other disturbance. Aspen subjected to herbivory, mainly mule deer (Odocoileus hemionus), either failed to regenerate successfully or regenerated at stem densities significantly lower than that on total-exclusion plots. Aspen did successfully regenerate on ungulate-use plots only when deer numbers were low. The addition of livestock grazing tended to reduce native grasses while promoting introduced species and bare soil. Kay and Bartos conclude that aspen stands in the Rocky Mountain west dominated by old or single-age trees are most likely a product of excessive ungulate browsing.
Article Summary / Main Points: None
Vegetation Types:
MLRA Ecoregions:
Agrovoc Control Words: Riparian zones Rangelands Wildlife
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: aspen, populus tremuloides, communities, reproduction, decline, cattle grazing, deer browsing, odocoileus hemionus, elk browsing, cervus elaphus, undergrowth
Annotation: Some of the exclosures were of a 2-part design where an inside area was fenced to exclude livestock, primarily cattle, but deer and elk had access. Adjacent unfenced outside plots were grazed by both wild and domestic ungulates. Other exclosures were of a 3-part design where 1 area was fenced to exclude all ungulates, another was fenced to excluded livestock, and outside areas were open to wild and domestic ungulates. Grazing intensity is not specified.
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