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Abstract Detail


Borowicz, Victoria A. [1].

Impact of the exotic invasive legume Lespedeza cuneata on demography of Pedicularis canadensis, a native parasitic plant.

Green parasitic plants (“hemiparasites”) acquire water, minerals, and organic compounds from neighboring plants via connections to the host vascular system. Hosts supply essential soil resources, but also cast shade, which can reduce photosynthesis and growth of hemiparasites. Together these positive and negative effects of neighbors can determine performance of individual hemiparasites. How such factors experienced by individuals affect hemiparasite population growth has received little attention. The goals of this study are to characterize the population structure of Pedicularis canadensis, a prairie root hemiparasite, and to examine effects of an exotic, invasive legume, Lespedeza cuneata, on P. canadensis demography. Pedicularis canadensis (wood betony) is a clonal, perennial, root hemiparasite found in open grasslands and woodlands of eastern and central US and Canada. This hemiparasite reaches high densities, especially on restored/reconstructed, nutrient-poor prairies. Once attaining a sufficient size, plants produce one to many inflorescences in April-May and senesce late in October. Host range is broad and includes L. cuneata. Lespedeza cuneata grows rapidly into dense stands that cast heavy shade and produce a thick layer of leaf litter rich in tannins. As a result of nitrogen fixation, L. cuneata may be especially valuable as a host for hemiparasites but also a strong competitor for light. In 2014, P. canadensis growing on a reconstructed tallgrass prairie were tagged and classified into one of five vegetative or 3 reproductive size classes. Plants were further classified as near (< 25 cm) or far from L. cuneata. The number surviving to spring 2015 was recorded and photosynthetically active radiation (PAR) was measured directly above each P. canadensis in July. Pedicularis canadensis located near L. cuneata experienced significantly lower light levels than hemiparasites more distant. Based on limited sample size and a single transition period, P. canadensis appears to be fairly resilient to shading by L. cuneata. Elasticity analysis suggests that the stages that are most sensitive to effects of L. cuneata have relatively little impact on the rate of population increase (λ). Lespedeza cuneata may have a larger indirect effect on demography of P. canadensis by suppressing native hosts.

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

invasive species

Presentation Type: Oral Paper
Session: 22, Ecology Section: Invasive Species
Location: 103/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 9:30 AM
Number: 22006
Abstract ID:646
Candidate for Awards:None

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