Publication Date

1997

Description

Atriplex canescens is a relatively widespread shrub in rangelands of the western United States,with a longstanding reputation as a valuable browse resource for ruminants. The breeding system of tetraploid populations has been extensively studied both in common gardens and in natural populations. However, browser-driven alterations of shrub sex ratios, and the probable mechanisms involved in such processes, have received relatively little attention in these populations. We report results from a preliminary study conducted in a stand of A. canescens at a site on the shortgrass steppe. Numbers of young shrubs decreased with increasing shrub density. Sex ratios did not differ from the expected 55:35:10 pistillate : staminate : monecious ratio in grazed plots, but did differ significantly from this ratio in exclosures, where they were clearly more female-biased. We discuss probable grazing-related mechanisms that could account for these results.

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Animal-Plant Interactions in an Atriplex canescens Dominant Community Browsed by Cattle

Atriplex canescens is a relatively widespread shrub in rangelands of the western United States,with a longstanding reputation as a valuable browse resource for ruminants. The breeding system of tetraploid populations has been extensively studied both in common gardens and in natural populations. However, browser-driven alterations of shrub sex ratios, and the probable mechanisms involved in such processes, have received relatively little attention in these populations. We report results from a preliminary study conducted in a stand of A. canescens at a site on the shortgrass steppe. Numbers of young shrubs decreased with increasing shrub density. Sex ratios did not differ from the expected 55:35:10 pistillate : staminate : monecious ratio in grazed plots, but did differ significantly from this ratio in exclosures, where they were clearly more female-biased. We discuss probable grazing-related mechanisms that could account for these results.