Competitive ability of the bunchgrass contribution of flexible allocation priorities to herbivory tolerance in C4 Schizachyrium scoparium as affected by grazing history and defoliation
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Authors: D. D. Briske, and V. J. Anderson
Date: 1992
Journal: Plant Ecology
Volume: 103
Number:
Pages: 41-49
Summary of Methods: In a transplant garden, Briske and Anderson grew the perennial bunchgrass, Schizachyrium scoparium, to test the hypothesis that late successional plant populations, with a history of grazing, are at a competitive disadvantage, relative to conspecific populations, with no history of grazing, in the presence of competition from mid-successional species. Plant and tiller variables of indicator plants, with a history of grazing, were equal to or greater than those of indicator plants with no history of grazing; with the single exception of individual tiller weight. Unexpectedly, plants with a history of grazing yielded greater annual production of Stipa neighborhoods than plants with no history of grazing, when neither indicator plants nor neighbors were defoliated. A reduction in mean tiller weight was the only variable to suggest that herbivore-induced selection conferred an associated cost to plants with a history of grazing. Plants with a history of grazing displayed equivalent or greater annual production, tiller recruitment, and basal area expansion than plants with no history of grazing. Comparable or greater performance by plants with a history of grazing indicates that the increase in relative density of mid-successional species within the neighborhood of the climax dominant, S. scoparium, following long-term severe herbivory in the southern true prairie, is not a consequence of a reduction in competitive ability in response to herbivore-induced population selection.
Article Summary / Main Points: None
Vegetation Types:
MLRA Ecoregions:
Agrovoc Control Words: Riparian zones Rangelands Grazing
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: herbivory resistance, grass-grazer interactions, population selection, selection pressure, tiller recruitment, bunchgrass, schizachyrium scoparium
Annotation: Herbivory was simulated by removing approximately 70% of above-ground biomass with clippers.,Data for all variables were collected in mid-April, early June, mid-August, and early October of 1987 and 1988, except for tiller number and basal area which were estimated in June and October each year.
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