Sensitivity of different grass functional groups to honey mesquite

Quantifying the relationship of different grass functional groups to increasing woody plant cover is necessary to better understand the effects of woody plant encroachment on grasslands. This study explored biomass production responses of three perennial grass groups based on photosynthetic pathway and potential canopy height (C4 short-grasses, C3 mid-grasses and C4 mid-grasses) to different percent canopy covers of the surrounding deciduous woody legume, honey mesquite (Prosopis glandulosa). Two methods were used to determine mesquite canopy cover, line-intercept and geospatial analysis of aerial images, and both were used to predict production of the 3 grass groups. Five years of grass production data were included in the mesquite cover/grass production regressions. Two years had extreme grass production responses, one due to drought and the other to high rainfall. Of the 3 remaining years, best-fit curves were negative linear for C4 short-grasses and C3 mid-grasses, and negative sigm..., Combination of data collected in the fiedl as well as analysis of aerial images of the research site., These are all Excel spreadsheets.