SPIRE: The Maine Journal of Conservation and Sustainability
University of Maine
Rising sea levels and coastal land use are predicted to synergistically impact coastal wetlands by reducing their extent and ecosystem functioning through a process known as “coastal squeeze”. Impervious surfaces associated with coastal development prevent the natural process of wetland migration, whereby intertidal wetland area is lost at its seaward edge to rising low water lines, but is replaced by eroding uplands and accumulating new wetland at its landward edge. As these constructed surfaces prevent the replacement of lost wetland, intertidal wetlands are “squeezed” by rising sea levels until they disappear. This study uses geographic information system (GIS) to predict changes in intertidal wetland position and losses due to coastal squeeze in a midcoast Maine estuary under a 2-m sea level rise scenario. Estimates range from a net loss of 28% to 57% in intertidal wetland coverage by year 2100. The lower end of this range includes some mitigation efforts like managed realignment projects. The disparity between the currently high area of intertidal wetlands and the available area for wetlands to migrate into maybe explained by local topography and artificially high sedimentation rates associated with historic land use.
McLachlan, JR (2018) High net loss of intertidal wetland coverage in a Maine estuary by year 2100. Spire: The Maine Journal of Conservation and Sustainability. Issue 2
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