Abstract Detail

Ecological Section

Borowicz, Victoria [1], Armstrong, Joseph E. [1].

The progressive invasion of an invasive legume, Lespedeza cuneata, in a restored tallgrass prairie.

The exotic legume Lespedeza cuneata, silky bush clover was present on this open, poor-soil site when we began a study in 2006, but it had not garnered our attention. At the time 108 permanent plots in 12 blocks were established to examine the effects of mineral nutrients, shade, and presence of the hemiparasitic plant, Pedicularis canadensis, in full replicate, on the tallgrass community. Lespedeza cuneata was present in the harvested center of 30% of experimental plots when we initiated the experiment in 2006, and in 82% of experimental plots by 2011. The plots will be sampled again in the fall of 2015. ANOVA of aboveground biomass at the end of 2011 showed that growth was significantly less in fertilized plots, and less in shaded plots, however, these effects depended on a hemiparasite removal treatment that increased growth of L. cuneata but only when the plot was fertilized and in full sun. These are the same conditions that favor grasses. Enhancing mineral nutrients has a negative influence on L. cuneata as an indirect effect of increased competition from grasses. In a three-way interaction shade & fertilizer significantly reduced the mass of SBC only when the hemiparasite was present. Rapid growth, a brushy structure, abundant seed production via selfing and outcrossing, and resistance to fire promote dense stands that are highly competitive against native species. In dense patches L. cuneata produces a heavy leaf litter layer that protects new aerial shoots and seeds from fire. Other studies have found the litter inhibits seed germination. Neither fall nor spring burning affects L. cuneata negatively, and heating enhances seed germination. L. cuneata is susceptible to herbicide treatments, but so are other forbs, and a considerable seed bank remains viable. By contrast the native Lespedeza capitata has maintained a steady population.

1 - Illinois State University, School of Biological Sciences, Campus Box 4120, Normal, IL, 61790-4120, USA

Keywords:
tallgrass prairie
invasive species
legume
Lespedeza cuneata.

Presentation Type: Oral Paper:Papers for Sections
Session: 9
Location: Salon 17/18/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 9:15 AM
Number: 9004
Abstract ID:882
Candidate for Awards:None