title: Do geographically isolated wetlands influence landscape functions?
abstract: Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs.
authors: School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611; mjc@ufl.edu.
authors: Matthew J
authors: MJ
authors: Cohen
authors: Department of Biology, Western University, London, ON, Canada N6A 5B7;
authors: Irena F
authors: IF
authors: Creed
authors: National Center for Environmental Assessment, United States Environmental Protection Agency, Washington, DC 20460;
authors: Laurie
authors: L
authors: Alexander
authors: Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada N2L 3G1;
authors: Nandita B
authors: NB
authors: Basu
authors: Department of Wildlife, Fisheries, and Conservation Biology, University of Maine, Orono, ME 04469;
authors: Aram J K
authors: AJ
authors: Calhoun
authors: School of Public Health and Environmental Affairs, Indiana University, Bloomington, IN 47405;
authors: Christopher
authors: C
authors: Craft
authors: CSS-Dynamac Corporation, Cincinnati, OH 45268;
authors: Ellen
authors: E
authors: D'Amico
authors: School of Natural Resource Sciences, North Dakota State University, Fargo, ND 58108-6050;
authors: Edward
authors: E
authors: DeKeyser
authors: Odum School of Ecology, The University of Georgia, Athens, GA 30602;
authors: Laurie
authors: L
authors: Fowler
authors: National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH 45268;
authors: Heather E
authors: HE
authors: Golden
authors: Soil and Water Science Department, University of Florida, Gainesville, FL 32611;
authors: James W
authors: JW
authors: Jawitz
authors: Region 4, United States Environmental Protection Agency, Athens, GA 30605;
authors: Peter
authors: P
authors: Kalla
authors: Joseph W. Jones Ecological Research Center, Newton, GA 39870;
authors: L Katherine
authors: LK
authors: Kirkman
authors: National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH 45268;
authors: Charles R
authors: CR
authors: Lane
authors: Department of Geographical Sciences, University of Maryland, College Park, MD 20742;
authors: Megan
authors: M
authors: Lang
authors: Western Ecology Division, National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Corvallis, OR 97333;
authors: Scott G
authors: SG
authors: Leibowitz
authors: Department of Integrative Biology, University of South Florida, Tampa, FL 33620;
authors: David Bruce
authors: DB
authors: Lewis
authors: CDM Smith, Inc., Indianapolis, IN 46204;
authors: John
authors: J
authors: Marton
authors: Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
authors: Daniel L
authors: DL
authors: McLaughlin
authors: Northern Prairie Wildlife Research Center, United States Geological Survey, Jamestown, ND 58401;
authors: David M
authors: DM
authors: Mushet
authors: Office of Wetlands, Oceans, and Watersheds, United States Environmental Protection Agency, Washington, DC 20460;
authors: Hadas
authors: H
authors: Raanan-Kiperwas
authors: School of Geosciences, University of South Florida, Tampa, FL 3362;
authors: Mark C
authors: MC
authors: Rains
authors: Joseph W. Jones Ecological Research Center, Newton, GA 39870;
authors: Lora
authors: L
authors: Smith
authors: Wetland and Aquatic Research Center, United States Geological Survey, Gainesville, FL 32653.
authors: Susan C
authors: SC
authors: Walls
mesh_terms: D008954:Models, Biological; D009656:North America; D053833:Wetlands
keywords: connectivity; navigable waters; significant nexus