Wetlands play an important role in the ecosystem and provide many ecosystem services such as erosion reduction, water filtration and creating diverse habitat for wildlife, leading to increased biodiversity. Urbanization, however, has varying effects on wetlands and their associated flora and fauna. This project aimed to determine the extent to which development affects the health and productivity of wetlands in an urban environment. As amphibians are a useful proxy of wetland health, it was important to identify habitat and environmental features of wetlands that affect amphibian diversity and population size. To complete this project, we looked at existing literature, performed call surveys and visual observations to document amphibians’ use of wetlands and devised survey criteria and protocols to assess the importance of different environmental factors. Specifically, we used criteria associated with pollution, impervious features such as roads, emergent vegetation, proximity to upland habitat, and wetland permanency and size. Working with the Miistakis Institute, as part of their Citizen Science Project, we gathered amphibian presence and absence data from across the City of Calgary, and we applied our survey protocols to 20 different wetlands spread throughout the city.
Results/Conclusions
We compared data on the presence and absence of various amphibian species to different environmental variables to determine the ability of our protocols to accurately predict amphibian use, and thus assess wetland health. Our analysis showed the importance of a few key variables that are essential for maintaining amphibian diversity. The proximity of wetlands to impervious features such as highways and roads were significantly related to amphibian occupancy. Roads, the associated noise pollution, and the amount of traffic all significantly influenced amphibian diversity. Roads and concrete structures also served to fragment wetland networks and reduced connectivity among wetlands and the upland habitat that is needed by many amphibian species. Our results also showed the importance of the amount of emergent vegetation; a lack of emergent vegetation reduced necessary breeding sites for amphibians and correlated with reduced occupancy levels. These findings are particularly important as many urban centers are currently struggling with how to protect and preserve wetland function in light of increasing urban development. By understanding what variables characterize healthy wetlands, cities will be better prepared to manage wetlands in an urban environment.