Grazing history, defoliation and competition: Effects on shortgrass production and nitrogen accumulation
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Authors: V. J. Jaramillo, and J. K. Detling
Date: 1988
Journal: Ecology
Volume: 69
Number: 5
Pages: 1599-1608
Summary of Methods: Jaramillo and Detling raised samples of blue grama (Bouteloua gracilis) from heavily grazed prairie dog (Cynomys ludovicianus) colonies and lightly grazed uncolonized sites in Wind Cave National Park, South Dakota, under controlled conditions to determine the impact of grazing history on several variables: production, nitrogen uptake, and biomass and nitrogen allocation following defoliation. Off-colony plants produced greater biomass (121%) and more nitrogen (203%) that on-colony plants. On-colony plants allocated greater biomass and nitrogen to roots than off-colony plants, which had greater allocation to leaf sheaths and reproductive structures. The authors note that the results support the hypothesis that genetically based morphological and physiological differentiation has occurred in blue grama as a result of strong selection pressures from grazing mammals on prairie dog colonies. They suggest that on-colony population displays a strategy that reduces grazing severity rather than a grazing tolerance response to aboveground herbivory.
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: blue grama, bouteloua gracilis, clipping, prairie dogs, cynomys ludovicianus, defoliation, grass, grassland, grazing history, nitrogen accumulation, nutrient accumulation
Annotation: Plants were subjected to one of three levels of defoliation (heavy, light, and no defoliation).
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