Author
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LEONARD, EAMONN - UTAH STATE UNIV. |
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Monaco, Thomas |
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Submitted to: Society of Range Management
Publication Type: Abstract Only Publication Acceptance Date: 2/5/2005 Publication Date: 2/5/2005 Citation: Leonard, E.D., Monaco, T.A. 2005. Implications of functional group diversity in shrub-steppe communities. Society of Range Management. Interpretive Summary: Technical Abstract: The importance of functional group diversity to the long-term structure and function of shrub-steppe plant communities is not well understood. Field experiments with prevalent Great Basin species were initiated to evalute the microenvironmental and structural variation in plots (1.5 x 1.5 m) assembled with monocultures or mixtures of grass, forb, and shrubs species. We hypothesized that plant assemblages with high functional group diversity more effectively utilize photosynthetically active radiation (PAR) and soil water than assemblages with low functional group diversity. First year results showed that surface soil water decreased with the following pattern: shrub mix>forb mix>grass mix>grass-forb-shrub. In monocultures, Agropyron cristatum had the lowest surface water. Leaf area index (LAI) decreased in the following pattern: forb mix>shrub mix>grass-forb-shrub mix>grass mix. Monocultures of A. cristatum maintained lower LAI than monocultures of Artemisia tridentata and Achillea lanulosa. Soil temperature was generally greater in the monocultures than in the mixtures. Soil temperatures were lower when forbs were present. These preliminary results suggest that higher functional group diversity promotes more complete resourse use and potentially fewer open niches for weed species to invade. These results will be a valuable contribution to future experiments designed to evalute the ability of these plant assemblages to resist weed invastion by Isatis tinctoria and Bromus tectorum. |
