Duchicela, Jessica , Vogelsang, Keith M , Schultz, Peggy A. , Kaonongbua, Wittaya , Middleton, Elizabeth , Bever, James .
Non-native plants and soil microbes contribute to reduced soil aggregate stability in disturbed N. American grasslands.
Soil aggregate stability is an important ecosystem property that reflects the soil vulnerability to erosion and its potential to sequester carbon. Soil aggregate stability has been shown to decline with anthropogenic disturbances, but the consistency, duration, and causes of these declines in aggregate stability are untested. We assessed aggregate stability in paired remnant and post-disturbance old fields across California grasslands, shortgrass prairie and tallgrass prairie. We found that the proportion of water-stable aggregates was lowest in shortgrass prairie and that sites recovering from anthropogenic disturbance consistently had lower aggregate stability than remnant sites, with the negative effect of a prior history of tillage being greater than that of grazing. Across all grasslands, non-native plant diversity was a significantly negative predictor of soil aggregate stability and mediates part of the effect of prior disturbance. The negative effect of non-native plants on aggregate stability was confirmed in a mesocosm experiment focusing on the California grasslands. Moreover, an inoculation study focusing on the tallgrass prairie soils demonstrated that the degradation of the microbial community also contributed to the decline in soil aggregate stability. Overall the results suggest that alteration of both plant and microbial composition underlie the continued prevents the recovery of aggregate stability following anthropogenic disturbance. Therefore, restoration practitioners need to address these biological components in the ecosystem in order to recover the important ecosystem service of soil stabilization.
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1 - Indiana University, Biology, Jordan Hall; 1001 East Third Street, Bloomington, IN, 47405, USA
2 - Indiana University, Biology, 1001 E. 3rd St., Jordan Hall 142, Bloomington, IN, 47405, USA
3 - Indiana University, 1001 E Third Street, Bloomington, IN, 47405, USA
4 - Indiana University, Biology, 1001 East Third Street, Bloomington, IN, 47405, USA
Presentation Type: Poster:Posters for Sections
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM