SFS Annual Meeting

5/22/2018  |   14:00 - 14:15   |  430 B

IMPACTS OF SEDIMENT DREDGING ON PHOSPHORUS DYNAMICS OF A RESTORED RIPARIAN WETLAND A wetland restoration project within the Muskegon Lake watershed (MI) was initiated in 2012 to hydrologically reconnect a former riparian wetland to its adjacent stream. The wetland complex was drained in the early 1900s for agricultural production but refilled naturally after farming ceased in the late 1990s. Initial studies indicated that the sediments contained significant amounts of legacy phosphorus (P), so hydrologic reconnection risked the net movement of P from the wetland complex to already eutrophic waterbodies downstream. Sediment dredging was selected to reduce this risk, which occurred in 2016. We evaluated restoration success by measuring sediment P release in the wetlands prior to, and after, dredging. Sediment cores were incubated under two water temperatures (ambient; +2°C) and two oxygen levels (oxic; hypoxic). Our results showed that the mean maximum total P release rate in all four post-dredging treatments was lower (mean±SD = 0.56 ± 4.2 mg m-2 d-1) than release rates of pre-dredging treatments (mean±SD = 65.9 ± 37.5 mg m-2 d-1), suggesting that sediment removal is an effective approach to reduce internal P loading of restored agricultural lands.

Kim Oldenborg (Primary Presenter/Author), Annis Water Resources Institute-Grand Valley State University , oldenbok@mail.gvsu.edu;


Alan Steinman (Co-Presenter/Co-Author), Annis Water Resources Institute-Grand Valley State University, steinmaa@gvsu.edu;


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5/22/2018  |   14:15 - 14:30   |  430 B

SELF-ORGANIZED MICROTOPOGRAPHY IN BLACK ASH WETLANDS IS DRIVEN BY HYDROLOGY Wetland microtopographic structure and its function has been the subject of research for decades, and several investigations suggest that microtopography is generated by autogenic ecohydrologic processes. But due to the difficulty of capturing the true spatial variability of wetland microtopography, many of the hypotheses for self-organization have remained elusive to test. We employ a novel method of Terrestrial Laser Scanning (TLS) that reveals an unprecedented high-resolution (<0.5 cm) glimpse at the true spatial structure of wetland microtopography in 10 black ash (Fraxinus nigra) stands of northern Minnesota, USA. Here we present the first efforts to synthesize this information and show that TLS can accurately locate microtopographic high points (hummocks), as well as estimate their height and area. Using these new data, we estimate distributions in both microtopographic elevation and hummock area in each wetland and relate these to monitored hydrologic regime; in doing so, we test hypotheses linking emergent microtopographic patterns to putative hydrologic controls.

Jake Diamond (Primary Presenter/Author), Virginia Tech, jacdia@vt.edu;


Atticus Stovall (Co-Presenter/Co-Author), University of Virginia, aes2aj@virginia.edu;


Daniel McLaughlin (Co-Presenter/Co-Author), Virginia Tech, mclaugd@vt.edu;


Rob Slesak (Co-Presenter/Co-Author), University of Minnesota, raslesak@umn.edu;


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5/22/2018  |   14:30 - 14:45   |  430 B

CHARACTERIZING VARIABILITY AND DRIVERS OF WETLAND STRUCTURE AT THE GREAT DISMAL SWAMP The Great Dismal Swamp (GDS) is a forested peatland located in the Atlantic Coastal Plain. Once a mosaic of wetland community types, anthropogenic disturbances (e.g., timber harvesting & ditching) have altered the historical hydrologic regime leading to a homogenization in forest communities and increased peat subsidence. To investigate the drivers of wetland structure, metrics of vegetation species composition and structure, seasonal hydrology, peat depth, and soil properties were collected at 88 monitoring plots across the GDS. These data were augmented with modeled mean growing season water table depth under a variety of hydrologic conditions (e.g., baseline wetness, wet year, & dry year). Community characterization using non-metric multidimensional scaling (NMDS) returned four significant groups, where groups with lower red maple IV had higher tree density and richness. Plot-level correlations comported with these results, yielding significant, although moderate, negative correlations between red maple IV and tree richness and density. Interestingly, hydrologic drivers explained only a small, albeit significant, amount of the observed community variation, prompting an investigation of additional drivers (e.g., site history & fire frequency) of wetland structure. These findings will inform ongoing, large-scale hydrologic restoration efforts at the GDS.

Raymond Ludwig (Primary Presenter/Author), Virginia Tech, rfludwig@vt.edu;


Daniel McLaughlin (Co-Presenter/Co-Author), Virginia Tech, mclaugd@vt.edu;


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5/22/2018  |   14:45 - 15:00   |  430 B

HABITAT STRUCTURE, HYDROPERIOD, AND TROPHIC COMPLEXITY OF PLAYA WETLANDS: A MESCOSM EXPERIMENT Ephemeral ecosystems fundamentally change throughout their hydroperiod which can subsequently change the food web. Direct experimentation in mesocosms allows exploration of how habitat structure, hydroperiod, and community assemblages all interact in the food web. Mesocosms were “seeded” with ephemeral wetland sediment and allowed to colonize throughout subsequent hydroperiods. Our experiment had two treatments: (1) a control group with sediment and water; and (2) and an enhanced habitat complexity group (plastic plants). Invertebrate community diversity and aspects of the trophic structure (size, redundancy, and variability) were tracked through the hydroperiod. Trophic structure metrics were measured using geometric properties of stable isotope (C13 and N15) biplots. Mesocosms generally gained species through time. The mesocosms with added habitat structure showed consistently more diversity, but were not significantly different. Trophic structure was more closely associated with insect diversity. Trophic structure was also more complex in mesocosms with more total, insect, and predator diversity. Structures that increases the hydroperiod, such as irregularities or deeper depressions in a playa floor, may impact playa invertebrates. Food web complexity is not simply associated with species richness numbers, but rather the characteristics of the individual taxa.

Brian O'Neill (Primary Presenter/Author), University of Wisconsin-Whitewater, oneillb@uww.edu;


James H. Thorp (Co-Presenter/Co-Author), University of Kansas/Kansas Biological Survey, thorp@ku.edu;


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5/22/2018  |   15:00 - 15:15   |  430 B

ENVIRONMENTAL FACTORS INFLUENCING AMPHIBIAN COMMUNITY ASSEMBLAGE IN DUNE WETLANDS ON THE LAKE MICHIGAN COAST Amphibian conservation has become increasingly important in recent years due to worldwide declines in amphibian biodiversity. Many amphibians utilize wetlands for habitat and breeding purposes, but current legislation limits wetland protection greatly, leaving many of these habitats unprotected. We analyzed amphibian species richness and environmental variables in 16 permanent and ephemeral wetlands along the coast of Lake Michigan in Grand Haven, MI from April to September of 2017. Nine species of amphibian were found: Green Frogs and Spring Peepers were most abundant; and Fowlers Toad was rarest. Wetlands in open dunes had significantly different species assemblages than those in forested habitat. Richness did not differ significantly between habitat types. Isolation score was significantly negatively correlated with species richness. Hydroperiod, area and depth were significantly positively correlated. Species richness was significantly positively correlated with hydroperiod and area. However, some small temporary wetlands situated in the open dunes harbored rare species not found in other wetlands. These findings highlight the importance of protecting all of these habitats from land development, fragmentation and degradation in order to conserve multiple species, as well as overall landscape connectivity of the system.

Alex Jouney (Primary Presenter/Author), Grand Valley State University, jouneya@mail.gvsu.edu;


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