Elevation gain vs. elevation functions.

<p>The empirical function utilized for marsh habitat elevation gain in the simulations is shown in black (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164875#pone.0164875.e001" target="_blank">Eq 1</a>), and two alternative elevation-gain functions that were used to test model sensitivity to uncertainty in elevation gain rates are shown in gray. Vertical lines show habitat zonation, with dashed lines indicating one standard deviation of the Gaussian distribution from which habitat transition elevations were selected.</p

Model results for the Anacostia River/Kenilworth Marsh area (NACE A).

<p>Beginning model land classifications for 2010 (following the initial time correction), and model results for the six scenarios.</p

Elevation change function (Eq 1) parameter values used.

<p>Elevation change function (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164875#pone.0164875.e001" target="_blank">Eq 1</a>) parameter values used.</p

Hypsometric curves of the surface elevation distribution.

<p>Data covers the entire study region, and is separated among the 3 different sea level rise scenarios. Cumulative area (x-axis) is the area with elevations exceeded by the corresponding elevation (y-axis) along each curve.</p

Modeled Tradeoffs between Developed Land Protection and Tidal Habitat Maintenance during Rising Sea Levels

<div><p>Tidal habitats host a diversity of species and provide hydrological services such as shoreline protection and nutrient attenuation. Accretion of sediment and biomass enables tidal marshes and swamps to grow vertically, providing a degree of resilience to rising sea levels. Even if accelerating sea level rise overcomes this vertical resilience, tidal habitats have the potential to migrate inland as they continue to occupy land that falls within the new tide range elevations. The existence of developed land inland of tidal habitats, however, may prevent this migration as efforts are often made to dyke and protect developments. To test the importance of inland migration to maintaining tidal habitat abundance under a range of potential rates of sea level rise, we developed a spatially explicit elevation tracking and habitat switching model, dubbed the Marsh Accretion and Inundation Model (MAIM), which incorporates elevation-dependent net land surface elevation gain functions. We applied the model to the metropolitan Washington, DC region, finding that the abundance of small National Park Service units and other public open space along the tidal Potomac River system provides a refuge to which tidal habitats may retreat to maintain total habitat area even under moderate sea level rise scenarios (0.7 m and 1.1 m rise by 2100). Under a severe sea level rise scenario associated with ice sheet collapse (1.7 m by 2100) habitat area is maintained only if no development is protected from rising water. If all existing development is protected, then 5%, 10%, and 40% of the total tidal habitat area is lost by 2100 for the three sea level rise scenarios tested.</p></div

Study area map.

<p>The eleven sub-regions are outlined in red boxes and labeled in white. Geographic features in the sub-regions include: PISC W- Marshall Hall; PISC E- Mockly Point and Piscataway Creek; GWMP A- Little Hunting Creek and Mount Vernon; GWMP B- Dyke Marsh; GWMP C- Broad Creek; GWMP D- Oxon Creek; GWMP E- Dangerfield Island and Reagan National Airport; NACE B- Anacostia Park; NACE A- Kingman Lake and Kenilworth Marsh; NACW A- Theodore Roosevelt Island and Columbia Island; LFalls- Chain Bridge and Little Falls. Black italic labels in the location map identify significant points on the Potomac River downstream of the study area: MH- Marshall Hall; IH- Indian Head; Q- Quantico; MP- Maryland Point; and US 301- US Highway 301 Bridge.</p

Habitat area through time for the 6 modeled scenarios.

<p>Solid lines are the median values of the 100 Monte Carlo runs, and the dashed lines are the 1^st and 3^rd quartiles.</p

Model results for the Broad Creek area (GWMP C).

<p>Beginning model land classifications for 2010 (following the initial time correction), and model results for the six scenarios.</p

Model results for the Piscataway Park area (PISC E).

<p>Beginning model land classifications for 2010 (following the initial time correction), and model results for the six scenarios.</p

Sea level rise scenarios.

<p>Sea level rise scenarios.</p