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There has been recent concern regarding the effects of range management practices on biodiversity. Our objective was to determine the long-term (~30 years) effects of chaining, and chaining followed by root plowing, on vegetation diversity in an ephemeral drainage system. Plant species richness and diversity were estimated in 2 chained (ca. 1950) areas, 2 chained (ca. 1950) and root-plowed (ca. 1960) areas, and 2 untreated areas during April 1993. Beta diversity within treatments was estimated with mean dissimilarity (l-mean similarity). Mean similarity was quantified with Jaccard's index. Spatial gradient analysis in which pairwise similarities were regressed against the distance between each pair of samples within a site was used to describe similarity within a site. Species richness and diversity were similar among treatments for both herbaceous and woody species. Similarity (Jaccard's index) among transects within a site increased with increasing degree of disturbance. Chained and root plowed sites had lower beta diversity than chained or untreated sites. Similarity in the chained and root plowed sites varied randomly, not spatially, while the control (untreated) and chained sites had negative spatial gradients, indicating spatial heterogeneity within these sites. Although root plowing did not reduce species richness and diversity as reported on upland sites in previous studies, beta diversity and habitat heterogeneity were lower on chained and root plowed sites than on chained or untreated sites.

During 5-d trials in spring and summer we investigated the constancy of creatinine and urea nitrogen excretion and the urea nitrogen:creatinine ratio in 24-h urine samples from 12 male white-tailed deer (Odocoileus virginianus) and the relationship of these metabolites with body mass and dietary nitrogen intake. During both trials, 24-h urinary creatinine excretion remained stable (CV of 13.5 and 18.5% for the spring and summer trials, respectively), and there was no difference between deer fed a high-protein diet and those fed a low-protein diet. However, urinary urea nitrogen excretion and urea nitr0gen:creatinine ratios were significantly lower in the latter group. Mean daily creatinine coefficients (0.22-0.27 mmol excretedlkg body mass) were comparable to those in other mammalian species. During both trials, urinary creatinine excretion was significantly related to body mass but not to dietary nitrogen intake. Urea nitrogen excretion and urea nitr0gen:creatinine ratios were significantly related to mass-specific nitrogen intake, but not to body mass or 24-h urinary creatinine excretion. Using 24-h urinary creatinine excretion, mean muscle mass of our deer was estimated to be 58 and 57% of whole body mass in the spring and summer trials, respectively.

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