Assembly through invasion and restoration: effects on biodiversity and ecosystem function

Kouri, Joshua

Assembly through invasion and restoration: effects on biodiversity and ecosystem function

dc.contributor.advisor	Souza, Lara
dc.contributor.author	Kouri, Joshua
dc.contributor.committeeMember	Moore, Abigail
dc.contributor.committeeMember	Marske, Katharine
dc.date.accessioned	2020-12-08T18:39:07Z
dc.date.available	2020-12-08T18:39:07Z
dc.date.issued	2020-12-18
dc.date.manuscript	2020-12-07
dc.description.abstract	It is well established that human activities have damaged many natural systems. Two critical aspects of mitigating this damage are identifying pathways to impacts and identifying the characteristics of successful interventions. We address both topics with a pair of independent studies linked by their focus on plant conservation. First, we investigated the ecological impacts of an invasive warm season grass on plant populations and communities in a temperate mixed-grass prairie ecosystem. Invasive plants are a well-known threat to native plant and animal communities and understanding their impacts is critical to developing management strategies. We investigated how impacts vary across a gradient of invasion and examined the impact of the invader on the intra- and inter-specific diversity of native plants. We found that most (but not all) impacts scale linearly as invader abundance increases. Increasing invasion reduced the height and abundance of the dominant native grass and shifted its functional trait composition (within-species effects). Increasing invasion also decreased total plant cover as well as the abundance of specific plant functional groups (inter-specific effects). We show that the direct ecological impacts of invasive species may be compounded by shifts in the functional traits of dominant native species. Second, we studied whether deterministic (initial seed mix of prairie restoration) or stochastic (establishment year precipitation) processes exert stronger influence on community function. It is critical to planning effective restoration actions to understand whether stochastic climate variation can influence the trajectory of restored communities. We calculated abundance-based community-weighted means (CWMs) of four functional traits across nine years post-restoration in two communities. We found that while climate differences led to dissimilar species compositions among restored communities, the CWMs of three of the four functional traits converged over time. This suggests that the function of restored communities is robust to variation in climate variables. The results of both studies provide valuable information for conservation practitioners.	en_US
dc.identifier.uri	https://hdl.handle.net/11244/326596
dc.language	en_US	en_US
dc.subject	biological invasions	en_US
dc.subject	plant ecology	en_US
dc.subject	restoration ecology	en_US
dc.thesis.degree	Master of Science	en_US
dc.title	Assembly through invasion and restoration: effects on biodiversity and ecosystem function	en_US
ou.group	College of Arts and Sciences::Department of Microbiology and Plant Biology	en_US
shareok.orcid	https://orcid.org/0000-0002-4129-0724	en_US