Recent Submissions

  • Influences of Seasonality and Habitat Quality on Great Lakes Coastal Wetland Fish Community Composition and Diets

    Diller, Sara N.; Harrison, Anna M.; Kowalski, Kurt P.; Brady, Valerie P.; Wilcox, Douglas A.; et al., See below for complete list of authors (Spring Nature, 2022)
    Great Lakes coastal wetlands (GLCW) have been severely degraded by anthropogenic activity over the last several decades despite their critical role in fish production. Many Great Lakes fish species use coastal wetland habitats for spawning, feeding, shelter, and nurseries throughout the year. The goal of our study was to compare GLCW fish community composition in the spring, summer, and fall months and investigate how water quality relates to fish diversity, the presence of functional groups, and juvenile fish diets. We summarized fish data collected from GLCW across the basin and used the coastal wetland monitoring program’s water quality-land use indicator to quantify water quality. Basin-wide, we found taxonomic and functional group differences in community composition among three sampling seasons, as well as across the range of water quality. Water quality was positively associated with the abundance of small cyprinids and the relative abundance of some habitat and reproductive specialists. Seasonal differences were also observed for many of these functional groups, with more temperature- and pollution- sensitive fishes captured in the spring and more nest-spawning fishes captured in the summer and fall. In our diet study, we found that age-0 fish primarily consumed zooplankton in the fall, whereas age-1 fish primarily consumed macroinvertebrates in the spring. Moreover, wetland quality was positively associated with trichopteran prey abundance. We concluded that taxonomic and functional composition of fish communities in GLCW vary markedly with respect to water quality and season. Thus, a full understanding of communities across a gradient of quality requires multi-season sampling.
  • Response of Typha to Phosphorus, Hydrology, and Land Use in Lake Ontario Coastal Wetlands and a Companion Greenhouse Study

    Hemingway, Aaron W.; Wilcox, Douglas A. (Springer Nature, 2022)
    Loss of Great Lakes wetlands due to changes in land use, hydrology, nutrient inputs, and invasive species led to the need for studies involving physical factors that influence growth of invasive cattails (Typha). Thus, in 18 Lake Ontario coastal wetlands, we sampled vegetation along stratified random transects and collected water samples for total phosphorus (TP) analyses. We used GIS to determine watershed area, percent land use as croplands, and length of lotic surface waters entering wetlands. A greenhouse growth experiment with a full factorial random block design was used to investigate the effects of variable hydroperiod and phosphorus concentrations on T. × glauca biomass changes. Correlation analyses of wetland data revealed that TP in field studies was related to percent croplands but not lotic length; mean percent Typha was not related to TP. In the growth experiment, above- and below-ground biomass increased significantly for simple main effects of hydroperiod and phosphorus concentrations. Multiple pairwise interaction comparisons between hydrology and nutrient treatments showed that effects of phosphorus concentration were present only at longer hydroperiods. Lack of correlation between Typha and phosphorus concentrations in the field was likely due to the overwhelming effect of water-level regulation on Lake Ontario. The greenhouse study demonstrated that increasing concentrations of phosphorus positively influenced cattail growth in a controlled setting. Although phosphorus positively influenced growth, hydrologic regime had the greatest influence on cattail growth, with increased biomass as hydroperiod increased. More natural hydrology and management of phosphorus inputs may help limit spread of Typha.
  • The impacts of Marcellus Shale Gas Drilling Accidents on Amphibians in a Pennsylvania Fen

    Graham, Andie; Wilcox, Douglas A. (Springer Nature, 2021-02)
    Gas drilling into the Marcellus Shale play has been linked to environmental issues, including potential impacts on wildlife. In 2009, three separate accidents occurred at two gas well sites in central Pennsylvania, USA that resulted in high levels of contaminants in Wallace Mine Fen and a headwater stream that flows through the fen. We collected water chemistry, vegetation, and amphibian data at the impacted fen and at a control fen in 2012 and 2013 to determine similarity of sites and the impacts of the contaminants. We also reviewed water chemistry reports generated by the Pennsylvania Department of Environmental Protection for data collected shortly after the accidents occurred to provide insight on the nature of the accidents. Ordinations of vegetation data, as well as water chemistry, showed that the two wetlands are similar and dominated by the same plant species and water chemistry. Historically, both wetlands provided habitat for amphibians. However, unlike in pre-accident amphibian data, we detected virtually no amphibians in the impacted Wallace Mine Fen, suggesting that amphibians were possibly negatively affected by gas-drilling accidents.
  • Extent of Sedge‑Grass Meadow in a Lake Michigan Drowned River Mouth Wetland Dictated by Topography and Lake Level

    Wilcox, Douglas A.; Bateman, John A.; Kowalski, Kurt P.; Meeker, James E.; Dunn, Nicole (Society of Wetland Scientists, 2022)
    Water-level fluctuations are critical in maintaining diversity of plant communities in Great Lakes wetlands. Sedge-grass meadows are especially sensitive to such fluctuations. We conducted vegetation sampling in a sedge-grass dominated Lake Michigan drowned river mouth wetland in 1995, 2002, and 2010 following high lake levels in 1986 and 1997. We also conducted photointerpretation studies in 16 years dating back to 1965 to include responses to high lake levels in 1952 and 1974. Topographic data were collected to assess their influence on areal extent of sedge-grass meadow. Dominant species in short emergent and submersed/floating plant communities changed with water availability from 1995 to extreme low lake levels in 2002 and 2010. Sedge-grass meadow was dominated by Calamagrostis canadensis and Carex stricta in all years sampled, but Importance Values differed among years partly due to sampling in newly exposed areas. Photointerpretation studies showed a significant relation between percent of wetland in sedge-grass meadow and summer lake level, as well as the number of years since an extreme high lake level. From the topographic map created, we calculated the cumulative area above each 0.2-m contour to determine the percent of wetland dewatered in select years following extreme high lake levels. When compared with percent sedge-grass meadow in those years, relative changes in both predicted land surface and sedge-grass meadow demonstrated that accuracy of lake level as a predictor of area of sedge-grass meadow is dependent on topography. Our results regarding relations of plant-community response to hydrology are applicable to other Great Lakes wetlands.
  • Groundwater Controls on Wetland Vegetation of a Ridge-and-Swale Chronosequence in a Lake Michigan Embayment

    Wilcox, Douglas A.; Mazur, Martha L. Carlson; Thompson, Todd A. (Society of Wetland Scientists, 2020)
    A chronosequence of wetland swales between beach ridges in the Manistique/Thompson embayments of Lake Michigan contains plant communities that differ across the strandplain.We characterized vegetation in 33 swales and compared distribution with previously reported groundwater flow systems. Older swales near a groundwater divide created by the peak Nipissing ridge receive local flows and hold sedge/leatherleaf floating mats that transition to swamp. Farther lakeward, another groundwater divide is created by discharge of calcareous waters released by termination of an underlying clay confining layer, resulting in swales dominated by northern white cedar. Cedar swamp continues lakeward in swales having flow-through calcareous groundwater, but several swales are perched above those flows. Farther lakeward, a large amalgamated beach ridge creates another groundwater divide with discharges that again support cedar swamp. Calcareous discharge from the confined aquifer, with downslope flow-through waters, then supports more cedar swamp. Flow-through waters meet yet another calcareous discharge, resulting in ponding and development of floating mats. Finally, a deep regional aquifer discharges at the Lake Michigan shore and supports marsh/shoreline species. Our results have implications for assessing potential responses to climate change, interpretation of past climate changes in paleoecological studies, and management of wetlands facing future climate changes
  • Hydrogeology and Landform Morphology Affect Plant Communities in a Great Lakes Ridge-and-Swale Wetland Complex

    Mazur, Martha L. Carlson; Wilcox, Douglas A.; Wiley, Michael J. (Wetlands, 2020)
    Trajectories of vegetative change in wetlands can be influenced strongly by shifts in water-table elevation driven by evapotranspiration and spatial-temporal variability in groundwater. The specific dynamics of such interactions are difficult to quantify because of spatial complexities associated with local climate, geomorphology, and underlying geology. Nonetheless, a better understanding of the effects of groundwater and landform pattern on plant communities in wetlands can help with future predictions of change. Over two successive growing seasons, we investigated water-balance dynamics in 15 wetlands in a forested Great Lakes coastal wetland complex consisting of relict beach ridges and intervening swales. Our goal was to explore how variation in hydrogeology and landform morphology affected plant community composition.Water-balance analyses from water-level fluctuation methods, along with interpretation of underlying stratigraphy and slope, were used to explain plantcommunity ordination results. Our findings showed that phreatophytic plant communities developed in locations where hydrogeology or greater slopes allowed for supplemental groundwater flow to the swales. Conversely, shallow water-table slopes maintained standing water in swales, leading to obligate wetland plant communities. This study provides a clearer representation of hydrogeologic and ecohydrologic interactions to help inform our understanding of the relationship between groundwater hydrology and plant communities in wetlands.
  • A Complicated Groundwater Flow System Supporting Ridge-and-Swale Wetlands in a Lake Michigan Strandplain

    Wilcox, Douglas A.; Baedke, Steve J.; Thompson, Todd A. (Wetlands, 2020)
    Beach ridges and wetland swales formed in embayments along Great Lakes shorelines during Holocene lake-level changes. Vegetation differences among swales suggested influence from differing groundwater flow systems. We characterized the hydrology across 79 ridge/swale wetlands in the Manistique/Thompson embayments of Lake Michigan using chemical and physical methods. Cross-sections were built from geologic data, and nested piezometers were installed across three ridges/swales where upwelling was noted. Stainless steel piezometers driven in 30 swales were sampled and water analyzed for specific conductance, alkalinity, and major ions. Surface water from 11 swales was analyzed. Water dominated by Ca-Mg-HCO3 was prevalent across the strandplain, with specific conductance generally less than 100 μS/cm. Conductivity, Ca, Mg, and HCO3 in groundwater were greater at identified groundwater discharges; where an amalgamated beach ridge forms a surficial groundwater divide; and swales nearer Lake Michigan that likely receive greatly mineralized water from a deeper aquifer. Repositioning of the shoreline as the embayments filled over the past 4700 years, coupled with isostatic rebound and changes in lake water levels, altered head differentials and changed the sources of discharge from local, intermediate, and deep flow systems over time. Extant plant communities are consistent with the groundwater dependence of these wetlands.
  • Leveraging a Landscape-Level Monitoring and Assessment Program for Developing Resilient Shorelines throughout the Laurentian Great Lakes

    Wilcox, Douglas A.; Uzarski, Donald G.; Brady, Valerie J.; Cooper, Matthew J.; Albert, Dennis A.; et. al., see listing below (Wetlands, 2019)
    Traditionally, ecosystem monitoring, conservation, and restoration have been conducted in a piecemeal manner at the local scale without regional landscape context. However, scientifically driven conservation and restoration decisions benefit greatly when they are based on regionally determined benchmarks and goals. Unfortunately, required data sets rarely exist for regionally important ecosystems. Because of early recognition of the extreme ecological importance of Laurentian Great Lakes coastal wetlands, and the extensive degradation that had already occurred, significant investments in coastal wetland research, protection, and restoration have been made in recent decades and continue today. Continued and refined assessment of wetland condition and trends, and the evaluation of restoration practices are all essential to ensuring the success of these investments. To provide wetland managers and decision makers throughout the Laurentian Great Lakes basin with the optimal tools and data needed to make scientifically-based decisions, our regional team of Great Lakes wetland scientists developed standardized methods and indicators used for assessing wetland condition. Froma landscape perspective, at the LaurentianGreat Lakes ecosystemscale, we established a stratified random-site-selection process to monitor birds, anurans, fish, macroinvertebrates, vegetation, and physicochemical conditions of coastal wetlands in the US and Canada. Monitoring of approximately 200 wetlands per year began in 2011 as the Great Lakes CoastalWetlandMonitoring Program. In this paper, we describe the development, delivery, and expected results of this ongoing international, multi-disciplinary, multi-stakeholder, landscape-scale monitoring programas a case example of successful application of landscape conservation design.
  • Selected Ecological Characteristics of Scirpus Cyperinus and Its Role as an Invader of Disturbed Wetlands

    Wilcox, Douglas A.; Pavlovic, Noel B.; Mueggler, Michelle L. (Wetlands, 1985)
    Scirpus Cyperinus (woolgrass) is a common invader of disturbed wetlands where soils have been exposed by water level reductions or vegetative cover has been reduced by various means. Its usual habitats include ditches, wet meadows, marshes and low, muddy grounds in the eastern United States and Canada. This study documents the encroachment of a woolgrass community onto well-decomposed organic soils exposed when long-term, industrial-related flooding of a wetland was terminated. Data were collected on spatial and temporal distribution patterns, species replacement, seed dispersal and growth, and environmental conditions. The ecological characteristics that enable Scirpus Cyperinus to be an effective colonizer were concluded to be: the vast number of seeds produced, effective dispersal of seeds, the clinging ability of seeds with long bristles, viability of the seeds stored in sediments, exclusion of other plants by a dense, perennial tussock growth form, and a fairly wide range of tolerance to environmental conditions.
  • Teaching Groundwater Hydrology in a Wetland Ecology Class

    Wilcox, Douglas A. (Wetland Science and Practice, 2020-01)
    I taught Wetland Ecology 25 times: 15 as an Adjunct Associate Professor at the University of Michigan and UM-Dearborn while I worked at the USGS-Great Lakes Science Center in Ann Arbor and 10 as the Empire Innovation Professor of Wetland Science at SUNY--The College at Brockport in my native western New York State. During the first year in giving the wetland hydrology lectures in Michigan, founded on water budgets, I realized that non-hydrology students had great difficulty understanding groundwater. They can see surface water and precipitation and likely learned about evapotranspiration in a plant ecology course. However, groundwater is an unseen mystery, and typical text material is too complicated to unravel that mystery. Fortunately, about that time, my friend, the late Tom Winter, handed me the new USGS Circular 1139 – Ground Water and Surface Water: a Single Resource (Winter et al. 1998), and I quickly realized that I had a solution.
  • Great Lakes Coastal Marshes

    Wilcox, Douglas A. (University of Calafornia, 2012)
    The Great Lakes system consists of Lakes Superior, Huron, Michigan, Erie, and Ontario, as well as their connecting channels and the St. Lawrence River, which connects the lakes to the Atlantic Ocean (Fig. 13.1). The Great Lakes Basin includes the Canadian province of Ontario and the U.S. states of Minnesota, Wisconsin, Illinois, Indiana, Michigan, Ohio, Pennsylvania, and New York. The basin covers about 765,000 km2, including the upper St. Lawrence River (Neff and Nicholas 2005).
  • The role of wetlands as nearshore habitat in Lake Huron

    Wilcox, Douglas A. (Ecovision World Monograph Series, 1995)
    Wetlands are generally considered to be among the most productive habitats on earth. As the landscape connection between upland and aquatic ecosystems, they possess many of the attributes of both systems and perform functions that extend well beyond the wetland boundary into both systems. In Lake Huron, wetlands comprise a small fraction of the total area, but they provide nearshore habitat for many plant and animal species that are deemed important for the lake as a whole. Thus, their role is an important one. In this paper, after describing the general functions and types of wetlands, I will explore the importance of wetland habitat in Lake Huron by defining its extent, describing physical and biological processes, summarizing biological uses, and detailing management problems.
  • Restoration of a Lake Ontario-connected fen through invasive Typha removal

    Graham, Andie; Mudrzynski, Bradley; Polzer, Eli; Wilcox, Douglas A. (Society for Ecological Restroation, 2022-04)
    Lake-level regulation that began in 1960 eliminated large fluctuations of Lake Ontario water levels, altering coastal wetland plant communities. More than a half century later, the altered hydroperiod supports dense, monotypic stands of invasive cattail (Typha angustifolia and Typha glauca), which have diminished overall plant community diversity. As a result, Lake Ontario coastal wetlands are less capable of providing many of their traditional ecological functions. One such wetland is Buttonwood Fen, a floating, lake-connected peatland on Lake Ontario’s southern shore near Rochester, NY. We implemented cattailcontrol measures from 2016 to 2018 with the goal of decreasing live and dead cattail biomass and increasing cover of native fen taxa. Site manipulation included removal of dead cattail biomass, cutting new cattail growth when rhizome carbohydrate reserves were at their lowest, and hand-wicking regrowth with herbicide in early fall. Results showed a decrease in live cattail stem density and cover and dead biomass cover, as well as an increase in cover of fen taxa. Although not a replicated study, our results suggest that removing dead cattail biomass and targeted treatment of live cattail stems via cutting and hand-wicking with glyphosate can reduce cattail and improve site quality.
  • Wetlands in Regulated Great Lakes

    Wilcox, Douglas A.; Meeker, James E. (U.S. Department of the Interior--National Biologicl Service, 1995)
  • Wetland and Aquatic Macrophytes as Indicators of Anthropogenic Hydrologic Disturbance

    Wilcox, Douglas A. (Natural Areas Journal, 1995)
    Hydrologic disturbance can affect wetland and aquatic macrophyte communities by creating temporal changes in soil moisture or water depth. Such disturbances are natural and help maintain wetland diversity; however, anthropogenic changes in wetland hydrology may have negative effects on wetlands. Since plant communities respond to habitat alterations, observations of plant-community changes may be used to recognize effects of hydrologic disturbances that are otherwise not well understood. A number of plants, including Typha angustifolia (narrow-leaf cattail) and Lythrum salicaria (purple loosestrife), are recognized as disturbance species; they are often fond in roadside ditches, in wetlands that have been partially drained, or in low areas that have been flooded. Other species commonly occur on mudflats exposed by lowering of water levels. In addition, wetland shrubs and trees invade of die as a result of draining or flooding. In more subtle terms, the relative composition of plant communities can change without the addition or loss of species, and zonation patterns may develop or change as a result of altered hydrology. Remote sensing (photointerpretation) and field vegetation studies, coupled with monitoring of water levels, are recommended for gaining an understanding of hydrologic diturbances in wetlands.
  • Response of wetland vegetation to the post-1986 decrease in Lake St. Clair water levels: Seed-bank emergence and beginnings of the Phragmites australis invasion

    Wilcox, Douglas A. (Elsevier, 2012)
    Water-level fluctuations are critical for maintaining the diversity and resultant habitat value of wetland plant communities in the Laurentian Great Lakes. However, activation of the seed bank can also provide an opportunity for invasive species to displace native species, as occurred when common reed, Phragmites australis, expanded across many wetlands after lake levels receded following highs in 1997. Timing of the invasion process is not clear, however, as Phragmites propagules had to be present to exploit the exposed soils. A data set from Dickinson Island on the St. Clair River delta collected in 1988–1991, 1996 during a previous lake-level decline was analyzed to document prior Phragmites growth, as well as overall seed-bank response. Aboveground biomass was determined for all plants each year in randomly placed quadrats in a 5-ha area exposed when lake levels decreased by 0.65 m from 1986 to 1988. A total of 38 taxa were identified in 1988, but the number decreased, along with biomass of many species, as canopy-dominating Typha angustifolia and Phragmites increased in later years. Although Phragmites did not expand greatly until after the decline from the 1997 high, it likely inoculated the area with viable seed during the previous low. Because post-1997 lake levels were lower than those post-1986, they exposed a greater area for Phragmites colonization from seed; lake levels also remained low for a longer time. Differences in bathymetry below the 1986 and 1997 lake-level elevations likely played a role in greater post-1997 spatial expansion of Phragmites at other sites in the Great Lakes also. The next high lake level will likely be required to displace Phragmites, but the effect will be temporary.
  • The Carbonate Chemistry of Green Lake, Jamesville, NY

    Effler, Steven W.; Field, Stephen D.; Wilcox, Douglas A. (Oikos Publishers, 1981-08)
    The temporal and vertical distributions of inorganic carbon and related forms were assessed for the mixolimnion of Green Lake, Jamesville, NY based on a biweekly monitoring program conducted for a 14-month period. The daily time structure of the distributions was delineated for a single diurnal cycle. Attendant [H2CO3] ([H2CO3] + [CO2 (aq)]) and calcite equilibrium conditions were determined through a solution of equilibrium equations, adjusted for temperature and ionic-strength. Inorganic carbon equilibrium conditions within the iron-rich chemocline/monolimnion were evaluated with the aid of a computer model, which incorporated ion-pair interactions, utilizing data obtained from a single sampling.
  • Meromixis and Stability at Green Lake, Jamesville, NY, Sept. 1977 - Nov. 1978

    Effler, Steven W.; Wilcox, Douglas A.; Field, Stephen D. (Oikos Publishers, 1981-08)
    The meromictic character of Green Lake, Jamesville, NY, is described based on a biweekly monitoring program conducted for 14 months. A sharp chemical gradient was observed in the lower waters throughout the study, supporting the classification of the lake as meromictic. An isodensity plot is presented for the study period. Densities were estimated with an equation of state obtained from the literature, which incorporated depth, temperature, and specific conductance information. Temporal variations in total stability are depicted, which were mitigated by seasonal thermal stratification. The chemical stability component remained constant (closed system value of 32.4 g-cm cm(-2)), and contributed only 5.7% to the total, for the maximum stability case. The work of wind in distributing the summer heat income (8,750 g-cl cm(-2)) was 348 g-cm (-2). Based on the identity of the chemically enriched forms within the chemline/monolimnion, the low magnitude of the chemical stability the large seasonal contribution of thermal stability to total stability, and the lake settling, it is probable that the lake is an example of biogenic meromixis.
  • Palaeohydrographic reconstructions from strandplains of beach ridges in the Laurentian Great Lakes

    Wilcox, Douglas A.; Johnston, John W; Thompson, Todd A. (The Geological Society of London, 2014)
    The current temporal and spatial context of water-level change, drivers of change, and possible future scenarios of the Laurentian Great Lakes is controversial. Palaeohydrographs are being constructed from measured subsurface elevations of palaeo-swash zones and modelled ages in strandplains of beach ridges that are preserved in embayments along the lakes’ edge. More than 800 elevations and 200 ages have been collected from 15 strandplains to construct site strandplain palaeohydrographs. Palaeo-beach elevations from whole strandplains or sets of correlative palaeo-beaches within strandplains are then used to establish an outlet palaeohydrograph for each lake. Adjusting strandplain palaeohydrograph elevations to account for glacial isostatic adjustment and refining age models help define the outlet palaeohydrograph. Common basin-wide water-level patterns and changes in outlet location or conveyance can then be interpreted. Systematic patterns of elevation and geomorphic/sedimentologic properties in individual, groups and sets of beach ridges in strandplains suggest that long-termpatterns of water-level change and sediment supply occurred on decadal, centennial and millennial scales. Outlet palaeohydrograph construction for Lake Superior revealed discrepancies between geological and historical rates of glacial isostatic adjustment. These differences are currently being investigated using new data from Lake Huron.
  • The effects of NaCl Deicing Salts on Sphagnum Recurvum P. Beauv

    Wilcox, Douglas A. (Environmental and Experimental Botany, 1984)
    In response to documented impacts of deicing salt runoff from a salt storage area along the Indiana Toll Road on the vegetation of Pinhook Bog, a student of the effect on NACl on one of the prominent bryophytes of the bog was initiated. Salt concentrations between 300 and 1500 mg/l as CL significantly reduced growth in length of Sphagnum recurvum in laboratory cultures. Growth in biomass was also reduced at higher concentrations under certain treatment conditions. Chloride appeared to be a greater growth inhibitor than chloride. In experiments in which water contact was reduced and evaporational plant surfaces increased, salt was deposited on plant tips through the evapotranspiration process, resulting in plant mortality at all NaCl concentrations tested. Washing of plant to simulate rainfall removed the salt encrustations, but they developed again quickly and produced similar lethal effects within 3 weeks of the last wash treatment. Since growth reduction and mortality of S. recurvum were shown at NaCl concentrations observed in Pinhook Bog, it is likely that deicing salts were responsible for the elimination of Sphagnum from the impacted area.

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