Does sericea lespedeza create a soil legacy that impacts grassland recovery?
Reichenborn, Molly M. Does Sericea Lespedeza Create a Soil Legacy That Impacts Grassland Recovery? --In Proceedings: 11th Annual Symposium on Graduate Research and Scholarly Projects. Wichita, KS: Wichita State University, p. 65
Sericea lespedeza (Lespedeza cuneata) is a non-native, invasive legume that is a growing threat to Kansas prairies. Current evidence suggests that sericea may alter soil conditions, potentially stimulating its own growth and negatively impacting native species in prairie communities. If correct, sericea may create a soil legacy effect even if control measures have effectively removed sericea, thereby slowing or preventing the recovery of native species. To test this idea, sericea was sown into 300 experimental plots at a wide range of densities (0 to 10,000 seeds m-2) in a prairie plant community located in Northeast Kansas. A fertilization and simulated disturbance regime was applied during the first two years of experimentation, along with appropriate ambient controls, during a previous experiment at the same site to examine the establishment of sericea under these regimes. After a three-year establishment period, the community was burned in the fall and sprayed with herbicide the following year to eliminate sericea. Following sericea control measures, thirteen native species were sown into all plots. The stem density of the sown native species was recorded in an annual census over the next four years. If sericea was found in any plots during this period, the stem density of sericea was recorded and individuals were manually removed. In addition, the percent cover of all species present in each plot was recorded in the final annual census. A significant effect of historical disturbance (Pseudo-F2, 243 = 2.8, P < 0.001) and fertilization (Pseudo-F1, 243 = 3.6, P < 0.001) was detected. Consequently, data were analyzed separately to account for these historical effects. Historical sericea stem density had no significant effect on the density of sown species (F1, 251 = 0.01, P > 0.9), but had a negative effect on native species cover within the simulated grazing (F1, 107 = 5.3, P = 0.02) and fertilization treatments (F1, 134 = 4.3, P = 0.04), however the variation explained by the model was quite low (R2 < 0.05 for both comparisons). Likewise, multivariate analysis of all species also indicated weak effects of historical sericea density. Taken together, these results suggest that sericea does not appear to create a soil legacy if controlled within the first three years of sericea establishment.
Presented to the 11th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Heskett Center, Wichita State University, April 24, 2015.
Research completed at Department of Biological Sciences, Fairmount College of Liberal Arts and Sciences & Department of Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas