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The impact of surrounding anthropogenic land-use on morphological characteristics and plant diversity in wetlands throughout Ohio

King, Christian, King
http://rave.ohiolink.edu/etdc/view?acc_num=osu1543248579203378

Abstract Details

2018, Master of Science, Ohio State University, Evolution, Ecology and Organismal Biology.
Anthropogenic land-use has led to substantial change and degradation of wetlands globally, as well as to the valuable biogeochemical and hydrologic services they provide. Both urbanization and agricultural intensification can negatively impact wetland characteristics such as size, shape and connectivity, which can in turn alter ecosystem processes and wetland communities. Of particular interest in wetland communities is the introduction of non-native species, which are prevalent in wetlands and may negatively influence native species in the community. Despite these well-recognized negative impacts, the effects of surrounding anthropogenic land-use on wetland characteristics and plant communities, as well as their underlying mechanisms, are poorly understood. To address this knowledge gap, we report on two studies conducted on wetlands throughout Ohio that examine the effect of surrounding land-use on wetland plant communities and wetland morphological characteristics respectively. The first study examines the change in wetland plant communities across an urban to rural gradient using vegetative field surveys and relates patterns of plant diversity to the environmental conditions and anthropogenic disturbance present in these wetlands. The second study explores variation in the morphological characteristics of wetlands with different surrounding land-use using a large-scale wetland inventory and evaluates the extent to which these characteristics may influence wetland plant communities. We tested a suite of hypotheses regarding how wetland morphological characteristics and wetland plant communities will vary with surrounding land-use. To evaluate changes in plant communities across the urban to rural gradient (Chapter 1), we conducted vegetative field surveys in 45 wetlands located across Ohio that were categorized depending on their surrounding land-use as either intensive urban, moderate urban, or rural. For each site, we measured the soil nutrient and element conditions, anthropogenic disturbance history, and plant community structure. We constructed structural equation models to determine the land-use dependent influence of environmental conditions and non-native diversity on native plant communities. We also evaluated mechanisms of disturbance to explain variation in diversity across the urban to rural gradient. In our field surveys, we found that intensive urban wetlands contained the highest number and greatest relative abundance of non-native species compared to rural wetlands. Increasing concentrations of heavy metals in intensive urban wetlands were associated with higher non-native relative abundance and lower native diversity. Additionally, non-native relative abundance negatively impacted the number of native species, with fewer native species present in wetlands with high relative abundances of non-native species. Lastly, spatial disturbance was highest in intensive urban wetlands and tended to be negatively related to native richness across sites. Within land-use categories, we found that plant diversity peaked at intermediate levels of disturbance, as expected, but only within intensive urban wetlands. To examine changes in wetland morphology with surrounding land-use and their impact on plant community structure (Chapter 2), we gathered data on the morphological characteristics of freshwater emergent wetlands throughout Ohio using the National Wetlands Inventory (NWI) database. We assessed differences in the morphological characteristics of size, shape and connectivity in wetlands that were predominantly surrounded by either natural, rural, moderate urban or intensive urban land-use. We also evaluated the importance of surrounding landscape variables, both anthropogenic and naturally occurring, in explaining variation in wetland morphological characteristics. Lastly, we determined any relationships between wetland morphology and plant community structure by conducting vegetative field surveys in a subset of the wetlands present in the database. We observed that wetlands surrounded by natural land-use were twice as large on average than both intensive and moderate urban wetlands, and 1.3 times larger than rural wetlands. Natural wetlands were also more irregularly shaped than both moderate urban and rural wetlands, with similar shape complexity to intense urban wetlands. Both natural and moderate urban wetlands contained the highest direct connectivity to hydrologic flow lines but were the most isolated in distance compared to rural and intensive urban wetlands. We found that both existing hydrological features and intensive urban land-use in the landscape were the most meaningful for explaining variation in wetland morphology. Of the morphological characteristics we examined, only shape appears to impact plant communities, with higher levels of non-native mean abundance and lower numbers of total and native species in irregularly shaped wetlands. Our findings from both studies suggest that intensive urban wetlands may be the most susceptible to the spread of non-native species due to their more complex shape, unique environmental conditions, and wide range of spatial disturbance. Intensive urban wetlands were the most complex in shape along with natural wetlands, with shape complexity being positively correlated to non-native mean abundance. Additionally, intensive urban wetlands contained the highest number and relative abundances of non-native species, which might be attributed to relatively high concentrations of urban heavy metals. Lastly, spatial disturbance tended to be negatively related to the number of native species, with intensive urban wetlands having the highest levels of such disturbances. Future management efforts should focus on mitigating environmental pollutants and restoring native species communities within intensive urban wetlands to improve the overall quality of wetlands in these environments.
Steve Hovick (Advisor)
Maria Miriti (Committee Member)
Desheng Liu (Committee Member)
103 p.
Ecology; Plant Sciences

Recommended Citations

Citations

  • King, King, C. (2018). The impact of surrounding anthropogenic land-use on morphological characteristics and plant diversity in wetlands throughout Ohio [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543248579203378

    APA Style (7th edition)

  • King, King, Christian. The impact of surrounding anthropogenic land-use on morphological characteristics and plant diversity in wetlands throughout Ohio. 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1543248579203378.

    MLA Style (8th edition)

  • King, King, Christian. "The impact of surrounding anthropogenic land-use on morphological characteristics and plant diversity in wetlands throughout Ohio." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543248579203378

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.