Master of Science (MS), Wright State University, 2018, Biological Sciences

Macroinvertebrates are important contributors to wetland ecosystems due to their role in decomposition, nutrient cycling, and as a food resource for other organisms. Several studies have analyzed the macroinvertebrate communities in created wetlands, but few have evaluated them in the context of trophic structure in both created and natural wetlands. The objective of this study is to better understand benthic macroinvertebrate community composition and trophic structure in created and natural wetlands. My central hypotheses were that macroinvertebrate communities in created wetlands would have (1) differing composition and (2) less complex trophic structure with shorter food-chain length compared to natural wetlands. Macroinvertebrates and soil cores were collected from five created and two natural depressional marshes. I assessed macroinvertebrate community characteristics such as diversity and composition, and functional feeding group composition. I used stable isotope analysis to determine food-chain length and other trophic metrics. Soil cores were used to determine bulk density, texture, and the C:N profile of the soil in the wetlands. Through a combination of univariate (e.g. ANOVA) and multivariate analyses (e.g. NMDS, PERMANOVA) these conclusions were met: (1) Macroinvertebrate taxa composition differed statistically between wetland types (p= 0.05); (2) FCL did not differ significantly between wetland types. In addition, functional feeding group composition was trending toward significance (p = 0.095), and soils were found to be distinct between wetland types (p= 0.043), with bulk density being a strong driver of that relationship (p= 0.012). These results show that in these wetlands, macroinvertebrate species present are different, however the overall function they provide are very similar between wetland types. The habitat characteristics in created wetlands that are known to quickly develop (e.g. plant community composition) were similar to the natural we (open full item for complete abstract)

Committee: Katie Hossler Ph.D. (Advisor); Yvonne Vadeboncoeur Ph.D. (Committee Member); Volker Bahn Ph.D. (Committee Member); John Stireman Ph.D. (Other) Subjects: Ecology; Entomology; Environmental Science; Environmental Studies

Master of Science, Miami University, 2012, Zoology

Wildfire disturbances affect resource availability and alter community composition in arid environments. Traditionally, fire effects on arid-land aquatic ecosystems are under-studied compared to terrestrial ecosystems. Chihuahuan Desert spring systems offer a unique opportunity to study such effects on macroinvertebrate community resistance and resilience. I took advantage of a rare opportunity to employ a BACI design to observe changes in water quality and macroinvertebrate communities to wildfire in a spring system on Bitter Lake National Wildlife Refuge, New Mexico. The results suggest significant water quality and species-specific response to wildfire. I observed an increase in an endangered snail, Juturnia kosteri, but there were no significant community-based changes. These results suggest that arid-land aquatic communities can be resistant to abiotic/biotic changes caused by wildland fire. With climate change predicted to increase the frequency and intensity of arid-land fires, aquatic communities may be more vulnerable to severe events in the future.

Committee: Dr. David Berg PhD (Committee Chair); Dr. Craig Williamson PhD (Committee Member); Dr. Ann Rypstra PhD (Committee Member) Subjects: Aquatic Sciences; Conservation; Zoology