Preliminary report of methodology and results for analysis of plant pattern subproject research on the Pawnee site

Abstract

Distributional forms and dispersion characteristics of Opuntia polyacantha were examined in areas subjected to three grazing treatment rates (light, medium, and heavy). Determinations of non-randomness were made from comparisons of observed numbers of individuals per quadrat to the expected number per quadrat derived from a Poisson series. Frequency data were obtained from transects of 256 contiguous dm sq quadrats in 30 m × 30 m study plots within each grazing treatment. The analysis of variance technique applied to the frequency data gave an estimate of the clump sizes within each treatment. Mean area of clumps for the light, medium and heavy grazing treatments were: 4, 16, and 128; 4 and 128; and 8, 32, and 128 dm, respectively.