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Do geographically isolated wetlands influence landscape functions?

December 28, 2015

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.

Citation Information

Publication Year 2015
Title Do geographically isolated wetlands influence landscape functions?
DOI 10.1073/pnas.1512650113
Authors Matthew J. Cohen, Irena F. Creed, Laurie C. Alexander, Nandita Basu, Aram J.K. Calhoun, Christopher Craft, Ellen D’Amico, Edward S. DeKeyser, Laurie Fowler, Heather E. Golden, James W. Jawitz, Peter Kalla, L. Katherine Kirkman, Charles R. Lane, Megan Lang, Scott G. Leibowitz, David Bruce Lewis, John Marton, Daniel L. McLaughlin, David M. Mushet, Hadas Raanan-Kiperwas, Mark C. Rains, Lora Smith, Susan C. Walls
Publication Type Article
Publication Subtype Journal Article
Series Title Proceedings of the National Academy of Sciences of the United States of America
Series Number
Index ID 70164512
Record Source USGS Publications Warehouse
USGS Organization Wetland and Aquatic Research Center