Do geographically isolated wetlands influence landscape functions?

Proceedings of the National Academy of Sciences of the United States of America
By: , and 

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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.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Do geographically isolated wetlands influence landscape functions?
Series title Proceedings of the National Academy of Sciences of the United States of America
DOI 10.1073/pnas.1512650113
Issue Early edition
Year Published 2015
Language English
Publisher Proceedings of the National Academy of Sciences
Contributing office(s) Wetland and Aquatic Research Center
Description 9 p.
Country United States
Online Only (Y/N) N
Additional Online Files (Y/N) N