Investigating the role of soil legacy effects and community engagement in the management of Lespedeza cuneata, an invasive legume

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Matthew Steven Hodges (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Invasive plant species present a growing threat to biodiversity. Many invasive plants are able to recruit microbial symbionts in their novel range and establish plant-soil feedbacks that influence growth and fitness. These alterations, referred to as soil legacy effects, can linger for decades after the removal of invasive species and impact efforts to restore native plant populations. The process of restoring organisms and their interactions with one another, referred to as ecological restoration, occurs by repairing these damages and alterations to ecosystem diversity and ecosystem dynamics. In a series of growth room experiments, I analyzed the plant-soil feedback of an invasive legume, Lespedeza cuneata, and how soil legacy effects caused by invasion and use of glyphosate herbicide influence the growth and competitive interactions of three native plant species. In contrast to studies of L. cuneata in prairie ecosystems, my investigation suggests that positive plant-soil feedback does not significantly contribute to its growth or spread in the floodplains of eastern North Carolina, as a history of invasion did not significantly improve the seed germination, seedling survival, growth, or root nodule formation of the invasive legume. The absence of evidence for positive plant-soil feedback in my experiment might be attributed to frequent flooding observed in a floodplain system and the resulting homogenization of soil biota. Findings from my study also suggest that the application of glyphosate herbicide alone creates areas where L. cuneata can readily reinvade, as it significantly reduced the number and diversity of seedlings to emerge from the seed bank while significantly increasing the aboveground biomass and nodule formation of L. cuneata. Concerning the restoration of native flora, my investigation suggests that Chasmanthium latifolium, as opposed to Solidago altissima or Chamaecrista nictitans, may be more susceptible to negative impacts caused by a L. cuneata invasion or glyphosate herbicide and therefore less suitable for initial efforts to restore populations of native flora. Results from my competition experiments also suggest that while S. altissima and Cham. nictitans may not be able to suppress populations of L. cuneata, the two native forbs would be successful in preventing areas from being reinvaded while areas occupied solely by Chas. latifolium may be at risk of reinvasion. Control of invasive species requires active participation by conservation professionals and the public. Outreach events and citizen-science programs can provide members of the community of all ages and careers the opportunity to play an active role in conservation efforts through data collection, species monitoring, restoration, invasive species removal, or a wide variety of other necessary tasks. To assess undergraduate attitudes towards conservation and involve students in the management of an invasive plant, an engagement event was held on a local greenway with an ongoing invasion of L. cuneata. During the outreach event, participants manually removed invasive plants while engaging in discussions centered on invasive species, local flora, and conservation. Voluntary participant data surveys suggested that the event positively impacted participants" perception of the natural world and encouraged them to seek out similar opportunities in the future. Survey results also showed that opinions towards conservation were influenced by the undergraduate major of students.

Additional Information

Publication

Thesis

Language: English

Date: 2020

Keywords

Lespedeza cuneata, Chinese lespedeza, plant-soil feedback, soil legacy effects, invasive species, invasive plants, outreach events, glyphosate

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