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Abstract Detail

Conservation Biology

Walder, Morgan [1], Borowicz, Victoria A. [1], Armstrong, Joseph [1].

Takeover on the Tallgrass Prairie: How Lespedeza cuneata Establishes Dominance.

Darwin’s naturalization hypothesis posits that an exotic species is less likely to establish in communities with closely related species because similarity in morphology and function among taxonomically related species would promote intense competition for resources. At fine scales this hypothesis predicts a negative correlation between abundance of an exotic species and the number of related species, and predicts that co-occurring species should differ in life history, morphology, and function in the community. We examined this hypothesis as it applies to Lespedeza cuneata, an exotic legume rapidly spreading through open, relatively infertile sites in the Midwest. Lespedeza cuneata has a greater biomass allocation to leaves resulting in a higher total leaf area as well as allelopathic leaf litter compared to its native congener, Lespedeza capitata. In addition, L. cuneata grows tall, coarse single stems that form large stands.
Timing of flowering, height of vegetative and flowering structures, total number of flowering stems of L. cuneata and all other species were recorded in 96, 1 m2 plots on a reconstructed tallgrass prairie in central Illinois, USA. Photosynthetically active radiation (PAR) was measured at ground level in June in each of the experimental plots, and biomass of grasses, forbs, L. cuneata, and other legumes were recorded from a 0.25 m2 subsample in each plot. These plots, established in 2006, had received annual treatments that were combinations of fertilizer (granular 10-10-10 N-P-K added/not added) and hemiparasite (Pedicularis canadensis removed/not removed). Principal components analysis was used to produce uncorrelated variables describing the composition of the plant community in the 1 m2 plots. Three factors explained approximately 71% of the variance in the data. These were included with fertilizer treatment, hemiparasite removal, and their interaction in analysis of variance of the dry mass of L. cuneata in the plots. Consistent with predictions of the naturalization hypothesis, L. cuneata biomass was negatively correlated with the number of other species of legumes present and also PAR. Other factors, which expressed the numbers of C3 and C4 grasses, forbs, weedy species, and exotic species in the community, were not associated with L. cuneata mass. Overall, fertilizer reduced L. cuneata biomass and hemiparasite removal had no effect. Lespedeza cuneata is the second-to-last species to flower on the study site and exhibits a growth form distinct from other legumes. The characteristics of L. cuneata seem to align with the naturalization hypothesis, but analysis is still in progress.

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

naturalization hypothesis
invasive species
prairie community
exotic legume.

Presentation Type: Poster
Session: P, Conservation Biology Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PCB013
Abstract ID:735
Candidate for Awards:None

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