The Relationship Between Monitoring and Range Condition Data

This study examined the relationships between range condition and nested species frequency and basal cover to determine if range condition could be predicted using these data. The study was conducted on Mixed Prairie vegetation near Wall and Lemmon in western South Dakota for one growing season. Data were collected on 7 vegetationally homogeneous 30 m x 50 m macroplots at each location for silty and thin upland range sites. Macroplots were chosen to represent a wide range of condition scores for each range site. Data were analyzed using stepwise multiple linear regression. Regression analysis of basal cover data resulted in non-normal residuals for both original and arcsin square root transformation data. Basal cover was subsequently dropped from analysis. The residuals from regression of the original and arcsin square root transformed species frequency data from the Lemmon thin upland data were also not normally distributed. No further analyses on these data were performed. The prediction equations for full models resulted in R2 values from 0.59 to 0.86. with 9 to 12 species variables present. R2 values ranged from 0.51 to 0.79 when the number of variables was restricted to five. Results indicate that species frequency data have the potential to predict range condition for grassland vegetation. Plant species that are important for these analyses are not necessarily the same as those having substantial influence in the SCS Technical Guides for range condition estimation. Some species that are not dominant (in terms of relative biomass) in climax may be of considerable value when species frequency is used for monitoring. Buffalo grass and June grass did illustrate important influences on range condition. These results demonstrate that some species are important in determining range condition regardless of the procedure used. The results show a relationship does exist between species frequency data and range condition on herbaceous plant communities. It also indicates it may be possible to develop practical field models with continued investigation on additional range sites and over several growing seasons