Food Web Structure in a Constructed Wetland
Wetlands are globally important ecosystems known for strong interactions among aquatic and terrestrial animals and plants. While natural wetlands are known for their complex food webs, constructed wetlands are often simpler, containing reduced levels of biodiversity. However, these systems generally reflect similar inter- and intra-specific interactions, with the advantage of having replicate sites. This project assessed food web interactions of macrofauna in ten wetland cells during an 8-week summer period in constructed wetlands at Kent State University. In each wetland cell, fish and amphibian (tadpoles/adults) assemblages were sampled twice/week using modified minnow traps to gain insight into population size and fish/amphibian size distributions. Next, to assess mammal and bird activity and their potential interactions in these wetlands, game cameras were strategically placed around each of the wetlands. Finally, odonates (i.e., dragonflies and damselflies) were also identified and counted in each wetland. Overall, species richness was relatively low, with only two fish species and two frog species captured from the minnow traps. In contrast, multiple mammal, bird, and odonate species were detected at the site in other sampling. Analyses of food web structure suggest a strong, negative relationship between sunfish abundance and frog/tadpole abundance and level of development, likely as a result of predation. The distribution of beavers, green herons, and great blue herons also appeared to be associated with food availability (woody vegetation for beavers, fish/frogs for herons). In summary, while simple, the food web in these constructed wetlands was structured similarly to what we see in natural wetlands.
Shvach, Kaitlin and Kershner, Mark(2019). Food Web Structure in a Constructed Wetland. Environmental Science & Design Research Initiative. Paper 45.