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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #184805
Title: DOES FUNCTIONAL GROUP DIVERSITY IN SHRUB-STEPPE COMMUNITIES REDUCE INVASION?

Author
item LEONARD, EAMONN - UTAH STATE UNIV.
item Monaco, Thomas

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/12/2006
Publication Date: 2/12/2006
Citation: Leonard, E.D., Monaco, T.A. 2006. Does functional group diversity in shrub-steppe communities reduce invasion?. Society for Range Management Meeting Abstracts.

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 evaluate the microenvironmental and structural variation in plots (1.5 x 1.5 m) assembled with monocultures and mixtures of grass, forb, and shrubs species. Seeds of grass (Bromus tectorum), shrub (Kochia prostrata), and forb (Isatis tinctoria) species were introduced into these plots in Fall 2004. We hypothesized that plant assemblages with high functional group diversity more effectively utilize photosynthetically active radiation (PAR), soil nutrients, and soil water than assemblages with low functional group diversity, which would in turn decrease the magnitude of species invasion. First year (2004) results showed that soil mineral-N content decreased with the following pattern: shrub mix>forb mix>grass mix>grass-forb-shrub. Leaf area index (LAI) decreased in the following pattern: forb mix>shrub mix>grass-forb-shrub mix>grass mix. Monocultures of Agropyron 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. B. tectorum invasion was highest in the A. lanulosa monoculture and was reduced when plots contained grass species. These preliminary results suggest that higher functional group diversity promotes more complete resource use and potentially fewer open niches for species to invade.