|Beck, K - COLORADO STATE UNIVERSITY|
Submitted to: Ecological Modelling
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2000
Publication Date: February 1, 2001
Citation: GOSLEE, S.C., PETERS, D.C., BECK, K.G. MODELING INVASIVE WEEDS IN GRASSLANDS: THE ROLE OF ALLELOPATHY IN ACROPTILON REPENS INVASIONS. ECOLOGICAL MODELLING. 2001. V. 139(1). P. 31-45. Interpretive Summary: We used an individual plant-based gap dynamics simulation model (ECOTONE) to evaluate the importance of allelopathy to invasion of semiarid rangelands by Russian knapweed. Experimental simulations used plots with one of four soil textures for a shortgrass steppe community in eastern Colorado. Model results showed that Russian knapweed did not dominate biomass unless native species were negatively affected by allelochemicals. At moderate levels of plant sensitivity, Russian knapweed dominated faster and reached a greater proportion of total biomass on fine- compared to coarse-textured soils. Dominance by Russian knapweed was more affected by sensitivity of growth by native grasses than sensitivity of recruitment. Our results indicate that Russian knapweed requires allelochemicals to dominate rangelands of Colorado.
Technical Abstract: We used an individual plant-based simulation model (ECOTONE) to evaluate the importance of allelopathy and soil texture to the invasion of semiarid grasslands by Acroptilon repens. We also assessed the sensitivity of model results to the negative effects of allelochemicals on recruitment and growth of perennial grasses. The ECOTONE model was parameterized for a shortgrass community in eastern Colorado. Experimental simulations used plots with four soil textures and a range of levels of plant sensitivity to allelochemicals. Simulation results showed that A. repens did not dominate the aboveground biomass unless native species were negatively affected by allelochemicals. At moderate levels of plant sensitivity, A. repens became dominant faster and reached a larger proportion of total biomass on fine- compared to coarse-textured soils. Community composition and rate of A. repens dominance were more affected by the sensitivity of plant growth to allelochemicals than sensitivity of recruitment. Allelopathic interactions were an important component of the invasion dynamics of this perennial invasive weed, and further field investigation is warranted.