Incorporating future change into current conservation planning: evaluating tidal saline wetland migration along the U.S. Gulf of Mexico coast under alternative sea-level rise and urbanization scenarios


Description

In this study, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, quantified the potential for landward migration of tidal saline wetlands along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on tidal saline wetlands (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse tidal saline wetland ecosystems into a single grouping, “tidal saline wetland” (TSWs). 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 the ecosystem goods and services provided by tidal saline wetlands. The primary product of this work is a public dataset that identifies locations where landward migration of tidal saline wetlands is expected to occur under alternative future sea-level rise and urbanization scenarios. In addition to identifying areas where landward migration of tidal saline wetlands is possible because of the absence of barriers, these data also identify locations where landward migration of these wetlands could be prevented by barriers associated with current urbanization, future urbanization, and levees.

Objectives

Investigate the following questions:

  • In which currently upland and/or freshwater wetland areas is landward migration of tidal saline wetlands likely to occur under alternative sea-level rise scenarios? Where are migration corridors located and how much area is available for migration?
  • Which of these migration corridors are currently urban or projected to be urban in the future? Such areas are likely to contain barriers to migration and result in reduced adaptation to rising sea levels. What is the human population of the migration corridors that are currently urban?
  • What is the current land use and land ownership of migration corridors?
  • How connected are future migration corridors to existing tidal saline wetlands in terms of quality and quantity?
  • How connected are future migration corridors to existing conservation areas and/or public lands?
Background

In the next 100 years, accelerated sea-level rise (SLR) and urbanization will greatly modify coastal landscapes across the globe. Historically, 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, 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. 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.

Methods

Geospatial data were used to address the following questions:

  • In which currently upland and/or freshwater wetland areas is landward migration of tidal saline wetlands likely to occur under alternative sea-level rise scenarios? Where are migration corridors located and how much area is available for migration?
  • Which of these migration corridors are currently urban or projected to be urban in the future? Such areas are likely to contain barriers to migration and result in reduced adaptation to rising sea levels. What is the human population of the migration corridors that are currently urban?
  • What is the current land use and land ownership of migration corridors?
  • How connected are future migration corridors to existing tidal saline wetlands in terms of quality and quantity?
  • How connected are future migration corridors to existing conservation areas and/or public lands?
Data Synthesis
Identify migration corridors and develop sea-level rise adaptation strategies to help ensure the continued availability of wetland-associated ecosystem goods and services.
References
  • Enwright, N.M., Griffith, K.T., and Osland, M.J., 2015, Incorporating future change into current conservation planning – evaluating tidal saline wetland migration along the U.S. Gulf of Mexico coast under alternative sea-level rise and urbanization scenarios: U.S. Geological Survey Data Series 969, doi: 10.3133/ds969
  • Enwright, N.M., Griffith, K.T., and Osland, M.L., 2016, Barriers to and opportunities for landward migration of coastal wetlands with sea-level rise: Frontiers in Ecology and the Environment, v. 14, p. 307-316, doi: 10.1002/fee.1282

Project Information