Paired-plot designs are commonly used to compare the effects of fire, grazing, or other disturbances. Plots are placed in treated (or disturbed) and untreated (or control) sites, and measured differences are meant to infer the direct effects of the treatments. As this next case study shows, such simple approaches are never as simple and straightforward as planned, but they do provide insightful information. This chapter is a case study designed to: (1) examine several aspects of plant assemblages at multiple spatial scales in long-term grazed and ungrazed sites in several management areas; (2) determine the relative roles of grazing, soil characteristics, and climate in determining patterns of species richness; and (3) develop broad generalizations about the effects of grazing and cessation of grazing on plant diversity in typical grasslands in the Rocky Mountains.
Keywords: spatial autocorrelation; exotic species; alien species invasions; paired-plot designs; plant assemblages
Chapter. 10795 words. Illustrated.
Subjects: Plant Sciences and Forestry
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