Fish Assemblages, Connectivity, and Habitat Rehabilitation in a Diked Great Lakes Coastal Wetland Complex

Abstract

Fish and plant assemblages in the highly modified Crane Creek coastal wetland complex of Lake Erie were sampled to characterize their spatial and seasonal patterns and to examine the implications of the hydrologic connection of diked wetland units to Lake Erie. Fyke netting captured 52 species and an abundance of fish in the Lake Erie-connected wetlands, but fewer than half of those species and much lower numbers and total masses of fish were captured in diked wetland units. Although all wetland units were immediately adjacent to Lake Erie, there were also pronounced differences in water quality and wetland vegetation between the hydrologically isolated and lake-connected wetlands. Large seasonal variations in fish assemblage composition and biomass were observed in connected wetland units but not in disconnected units. Reestablishment of hydrologic connectivity in diked wetland units would allow coastal Lake Erie fish to use these vegetated habitats seasonally, although connectivity does appear to pose some risks, such as the expansion of invasive plants and localized reductions in water quality. Periodic isolation and drawdown of the diked units could still be used to mimic intermediate levels of disturbance and manage invasive wetland vegetation.

Lakescape connectivity: Mobile fish consumers link Lake Michigan coastal wetland and nearshore food webs

“…Habitat diversity among coastal wetlands across the Great Lakes is large (Keough et al, 1999), and even within a wetland, different microhabitats can provide refugia and/or forage, such as submergent or emergent vegetation (Kovalenko et al, 2018). Therefore, maintaining lakescape connectivity by reconnecting diked wetlands (Kowalski et al, 2014) or reengineering coastal infrastructure (Bulleri & Chapman, 2010), in addition to protecting a diversity of wetland habitats, is likely crucial for preserving fish‐mediated trophic linkages that support nearshore fisheries production, as well as for the physical exchange of resources (e.g., prey fishes and seston).…”

Influences of seasonality and habitat quality on Great Lakes coastal wetland fish community composition and diets

“…Moreover, acknowledging seasonal differences in fish communities could also have implications for restoration and management of diked GLCW. Not only do many fish species access restored habitats throughout the year (Kowalski et al 2014), but this study shows how the composition of fish assemblages changes throughout the year. This information could help managers evaluate potential impacts on fish resources during temporary re-isolation of diked wetlands.…”

Fish and crustaceans provide early indicators of success in wetland restoration

“…BRUVS, however, were not effective at measuring changes to the abundance of individual fish and crustacean species and this is likely because large fish and crustaceans are less abundant in the early stages of wetland restoration projects (Boys & Pease 2017). By contrast, fyke nets were more effective for detecting early shifts to small and juvenile fish and crustacean assemblages which are typically highly abundant in the early stages of wetland restoration projects (Kowalski et al 2014; Lechêne et al 2018; Baker et al 2020). However, we experienced high variability in individual species abundance which contributed to large confidence intervals and may become problematic for identifying trends over large temporal and spatial scales.…”