Jenna Odegard's Graduate Defense Seminar

A Graduate Defense Seminar will be presented by Jenna Odegard, MS candidate in Fisheries and Wildlife Science. Her presentation will be The Role of Functional Diversity in Biotic Resistance of Non-native Fishes and Invertebrates in Lake Erie Coastal Wetlands. This seminar will be held in 333 Kottman Hall.

Biological invasions are a leading cause of biodiversity declines and impairment of ecosystem function. Native communities that resist invasion by non-native species are frequently thought to be more diverse (i.e. diversity-invasibility hypothesis, DIH). This “biotic resistance” to non-natives by a more diverse community of native species is thought to occur through increased interspecific competition, more fully used resources, and less available niche space. Evidence in support of the biotic resistance is mixed, suggesting that the DIH relationship depends on spatial scale (e.g. “invasion paradox”); however, another factor influencing the relationship between native and non-native species might be how diversity is measured. Most research that examines whether more diverse communities are more resistant to invasion has typically focused on measuring taxonomic biodiversity; however, functional diversity (e.g. feeding groups) might also be an important factor contributing to a native community’s biotic resistance.

In this study, we investigated if there is support for DIH in fish and invertebrate assemblages in Lake Erie coastal wetlands, according to taxonomic and functional richness and diversity. We sampled native and non-native fishes and invertebrates between 2013 and 2016. We expected to find a negative association between native and non-native organisms; however, when investigating the relationship between fishes and presence of non-native invertebrates, we found a positive relationship. We did not find a significant (positive or negative) relationship when investigating the relationship between natives and non-natives in each assemblage. Explanations for this positive relationship between  fishes and presence of non-native invertebrates might be related to spatial scale of the study and facilitation, while factors influencing the lack of other relationships might be related to how we assessed the biotic community and time since invasion. Assessing these trends is important for reducing costly impacts of invasion, prioritizing management efforts, and conserving native species.

Suzanne Gray and Lauren Pintor, co-advisors