Date of Award

January 2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Mark A. Kaemingk

Abstract

The Prairie Pothole Region (PPR) of North America is home to dynamic glacier-formed lakes and wetlands that range in size from small intermittent wetlands to large permanently filled basins. Predicting water-related shifts in environmental conditions and biological community responses within these systems has been challenging due to non-linear, scale-specific changes. Furthermore, landscape-level changes in the quantity and distribution of surface water are becoming more frequent. This thesis contributes to our understanding of how waterbody size, and potential size fluctuations, influence chemical and community dynamics of complex PPR glacial lakes and wetlands. We paired remote sensing and discontinuity methods with US Geological Survey long-term monitoring data to evaluate intrinsic waterbody size scales over multiple large spatial and temporal scales within North Dakota. Our first chapter assessed waterbodies in Kidder and Stutsman Counties, ND within 2012 to determine if abiotic or biotic dependencies exhibited linear, non-linear, or scale-specific patterns. Our second and third chapters assessed hydrological changes of wetlands in the Cottonwood Lake Study Area (CLSA), ND between 2009-2020 and potential biological shifts through time. We assessed the landscape for a hydrological regime shift and potential biological consequences. Additionally, we evaluated wetlands based on size to distinguish if communities varied between small (≤ 1 ha) and large (> 1 ha) wetlands. In waterbodies of Kidder and Stutsman Counties, we identified both linear (n=11) and scale-specific (n=9) patterns of water chemistry variables and scale-dependencies of fathead minnow (Pimephales promelas). The landscape of the CLSA experienced a hydrological shift between 2014 and 2015 (i.e., two regimes: 2009-2014, 2015-2020) and significant shifts in specific conductivity and macroinvertebrate and breeding bird communities. Over the eleven-year period a significant loss in small wetlands (≤ 1 ha) at CLSA was observed. Small wetlands were disproportionately affected by the drying period, and we also determined these wetlands (≤ 1 ha) support unique overall communities and specific taxa across multiple trophic levels compared to large wetlands (> 1 ha). This thesis demonstrates that remote sensing paired with discontinuity techniques can be a useful approach to assess lentic systems at multiple spatial and temporal scales.

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