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Competitive ability of the bunchgrass Schizachyrium scoparium as affected by grazing history and defoliation
Author
Briske, D. D. Anderson, V. J.
Publication Year
1969
Body

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.

Language
en
Collection
Range Science Information System
Keywords
Schizachyrium scoparium
bunchgrass
grass-grazer interactions
herbivory resistance
population selection
selection pressure
Tiller recruitment
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