Tidal Saline Wetland Migration (2100)

In the next 100 years, accelerated sea-level rise (SLR) and urbanization will greatly modify coastal landscapes across the globe (Millennium Ecosystem Assessment, 2005; Stocker and others, 2013). More than one-half of coastal wetlands in the contiguous United States are located along the Gulf of Mexico coast (Field and others, 1991). In addition to supporting fish and wildlife habitat, these highly productive wetlands support many ecosystem goods and services including storm protection, recreation, clean water, and carbon sequestration (Barbier and others, 2011; Engle, 2011). Historically, tidal saline wetlands (TSWs) have adapted to sea-level fluctuations through lateral and vertical movement on the landscape. As sea levels rise in the future, some TSWs will adapt and migrate landward in undeveloped low-lying areas where migration corridors exist (Doyle and others, 2010, 2015); however, where naturally occurring and human-created barriers are present (such as natural bluffs and seawalls or levees, respectively), landward wetland migration will be prevented (Titus and others, 2009; Pace, 2010). To sustain or manage the ecosystem goods and services provided by TSWs for current and future generations, natural resource managers and planners need to understand where TSW migration is most likely to occur under a suite of region-wide SLR and urbanization scenarios. 

In this study, the U.S. Geological Survey (USGS), in cooperation with the U.S. Fish and Wildlife Service (USFWS), quantified the potential for TSW landward migration along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on TSWs (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse TSW ecosystems into a single grouping, “tidal saline wetland.” Collectively, our approach and findings can provide useful information for scientists and environmental planners working to develop future-focused adaptation strategies for conserving coastal landscapes and TSW ecosystem goods and services. The primary product of this work is a public dataset that identifies locations where TSW landward migration is expected to occur under alternative future SLR and urbanization scenarios. In addition to identifying areas where TSW landward migration is possible because of the absence of barriers, these data also identify locations where TSW landward migration could be prevented by barriers associated with current urbanization, future urbanization, and levees. The dataset includes five time steps (2030, 2040, 2050, 2060, and 2100), five SLR scenarios (0.5-, 1.0-, 1.2-, 1.5-, and 2.0-meter [m] SLR by 2100), and three uncertainty categories, which equates to 102 total files because of the presentation of the data in two formats, as well as the various time step/scenario-uncertainty combinations.