A Continuum of Connectivity: Geographically Isolated Wetlands and the Conservation of Landscape Functions

Matthew J Cohen, University of Florida, Water Institute, Gainesville, United States, Irena F Creed, University of Western Ontario, Department of Biology, London, ON, Canada, Nandita B Basu, University of Waterloo, Department of Civil and Environmental Engineering, Waterloo, ON, Canada, James W Jawitz, University of Florida, Department of Soil, Water, and Ecosystem Sciences, Gainesville, United States, Daniel L Mclaughlin, Virginia Polytechnic Institute and State University, Forest Resources and Environmental Conservation, Blacksburg, United States and Mark Cable Rains, University of South Florida, School of Geosciences, Tampa, United States
Abstract:
Landscape functions depend on how matter, energy, and organisms exchange between elements in hydrologic and habitat networks. Wetlands are important network elements, providing hydrological, biogeochemical and biological functions that vary along a continuum of connectivity with nearby and downstream waters. Geographically isolated wetlands (GIWs), those surrounded by uplands, occupy the entire connectivity continuum, but generally fall outside US legal protections unless a “significant nexus” to navigable waters is demonstrated. Geographic isolation does not imply hydrological, biogeochemical or biological isolation. Here we show multiple lines of evidence to support the inference that GIWs are integral to the function of navigable waters. Moreover, while GIW hydro-chemical connectivity may be episodic or slow (e.g., via groundwater), and biological connectivity limited by overland dispersal, reducing material or organism exchange is specifically what enables important, sometimes unique, functions. This relational connectivity, wherein precluded exchange creates functionality, may be as important to downstream waters as more obvious connections. Logic and evidence support the presumption that anthropogenic changes to GIW prevalence, condition and connectivity have significant downstream impacts.
Back to: Cryptic Wetlands and Incognito Streams: Connectivity of Headwaters to Downstream Receiving Waters and Impacts on Water Quality and Ecological Functions II