Invasion of grasslands by exotic perennial weeds: Allelopathy and soil texture effects

TitleInvasion of grasslands by exotic perennial weeds: Allelopathy and soil texture effects
Publication TypeConference Paper
Year of Publication1999
AuthorsGoslee S.C., Peters DC, Beck K.G.
Conference Name84th Annual Meeting of the Ecological Society of America
Date Published1999
Conference LocationSpokane, WA
ARIS Log Number100292
KeywordsAllelopathy, grasslands, invasion, perennial weeds, soil texture
AbstractInvasion of native ecosystems by exotic perennial weeds is an increasingly important ecological problem, yet the key processes involved remain poorly understand for many species. Our objective was to evaluate the importance of allelopathy to the invasion by Acroptilon repens (Russian knapweed) into native semiarid grasslands. Based upon the inverse texture hypothesis, we expected the strength of the allelopathic affect to be related to soil texture and its effects on soil water availability. We used an individual plant-based simulation model (ECOTONE) to evaluate the importance of allelopathy to invasion by Russian knapweed into shortgrass communities in eastern Colorado over a range of soil textures. We found that allelopathy was more important for fine-textured soils where allelochemicals became concentrated in the rooting zone of grasses compared to soils with high sand contents where leaching of allelochemicals occurred. Rates of invasion nwere faster and more complete dominance by Russian knapweed occurred on fine- compared to coarse-textured soils. Our results have important implications for the management and sustainability of these grasslands under the threat of invasion by perennial weeds.