The concept at the heart of the study is known as escape habitat planning. As climate change pushes ecosystems beyond their historical ranges, species must either adapt in place or move to survive. For coastal wetlands, movement means migrating landward, a process that requires both vertical space for sediment accumulation and lateral space for wetlands to form on adjacent uplands. When seawalls, roads, and subdivisions block that retreat, habitats become squeezed between rising water and immovable infrastructure, a phenomenon ecologists call coastal squeeze. In the southeastern United States, projections suggest up to two-thirds of future wetland migration will come at the expense of freshwater wetlands, while the remainder will consume already fragmented uplands, many of which harbor endemic species found nowhere else.

Florida presents a uniquely difficult case. The state’s 1,931-kilometer coastline is home to more than two-thirds of its 23.4 million residents, and its flat topography and porous limestone bedrock make it exceptionally vulnerable not only to inundation but to saltwater intrusion into the aquifers that supply most of its freshwater. Projections indicate that up to 2 meters of sea-level rise could flood more than 7,770 square kilometers of the state, with the southern Gulf Coast and the Everglades bearing the brunt. Coastal forests are already converting to ghost forests, landscapes of dead trees killed by inundation and salt, while nearly half of Florida’s island-dependent species face major extinction risks. Yet some systems retain mobility: salt marshes can transgress landward, and mangroves are expanding northward as freeze events become rarer.

The research team built and compared two complementary models. The first, the Florida Ecological Greenways Network Coastal-to-Inland Connectivity Model, is deliberately simple. Using Esri’s Cost Distance tool and the state’s Cooperative Land Cover dataset, it treats all undeveloped, ecologically suitable land as equally permeable, assigning a uniform resistance value of one, and then calculates continuous pathways along which coastal natural communities could theoretically migrate inland. The study area was delineated using NOAA’s 3-meter sea-level rise model with an additional two-mile buffer. This data-efficient approach is highly transferable to other regions and is intended to support strategic land acquisition decisions with minimal input requirements.

The second model, the Integrated Coastal Connectivity Model, is far richer in data. Built with Omniscape, a circuit-theory-based connectivity tool implemented in the Julia programming language, it combines expert-ranked land cover classifications with high-resolution flood hazard maps from JBA Risk Management, topographic diversity data derived from satellite elevation products, and sea-level rise projections from two established marsh migration models. On the Gulf Coast, the team used the Sea Level Affecting Marshes Model, or SLAMM, a tool originally developed in the mid-1980s with funding from the U.S. Environmental Protection Agency that simulates inundation, erosion, sediment accretion, overwash, saturation, and salinity shifts. Along the Atlantic coast, where comprehensive SLAMM results were unavailable, they substituted the NOAA Marsh Migration Model, which combines land cover data, digital elevation models, and tidal datum surfaces to project marsh persistence, migration, or loss.

One of the study’s most technically interesting choices involves how water itself was parameterized. The researchers tested scenarios in which open marine areas were assigned extreme resistance values and found that both extremes distorted the results. Assigning a value of ten, intended to represent high permeability, inadvertently created artificial islands of low resistance surrounded by higher-resistance matrices, while a value of zero blocked movement entirely. They settled on an intermediate, neutral value of six, which better captured continuous ecological flow along the coastline. Flood data was processed using fuzzy logic, with a gamma overlay combining weighted fuzzy sums and products to highlight areas that flood repeatedly across multiple return periods, from 20-year to 1,500-year events, rather than treating each flood scenario independently.

The results reveal both convergence and striking divergence between the two approaches. The simpler cost-distance model identified its most extensive migration corridors in the Big Bend and Panhandle regions, where natural land cover remains intact, and highlighted the Suwannee River basin and Apalachicola lowlands as critical connectivity zones. The integrated model showed that under a 1-meter rise, many low-lying Gulf Coast wetlands would be inundated, shrinking corridors to localized pockets, and under 2 meters, connectivity would collapse further across southwest Florida and the Big Bend. Agreement between the two models fell as low as 59 percent in some regions, and adding topographic diversity to the resistance surface reduced agreement by an additional 5 to 10 percent, a finding the authors did not fully anticipate.

That divergence may be the study’s most consequential insight. Florida is often perceived as uniformly flat, but its subtle microtopography, relict dune ridges, karst features such as sinkholes and springs, and slight elevation gradients, has shaped its biodiversity for millennia. Over successive cycles of rising and falling seas, populations isolated on upland ridges evolved into endemic species through allopatric speciation. The integrated model’s sensitivity to topographic diversity suggests these modest features act as stepping stones and microrefugia, offering drier soils, thermal variation, and resistance to inundation. Conserving geophysically complex areas slows the velocity of climate change exposure for species and provides microclimates that buffer against extremes, meaning that even centimeter-scale terrain variation matters when the entire landscape sits barely above the tide line.

The practical payoff comes in the form of land acquisition priorities. The team overlaid their connectivity outputs on the Florida Forever Board of Trustees Projects layer, which catalogs 362 proposed conservation land purchases not yet protected, and ranked roughly 19,000 individual parcels based on corridor overlap, watershed priority, and elevation. Agreement between the two models increased steadily with ranking quality, from 29.45 percent in the lowest 30 percent of parcels to 63.60 percent in the top 10 percent. In other words, while the models disagree about lower-priority areas, they converge substantially on the highest-value conservation targets, and many of those top-scoring parcels already align with existing state acquisition goals. This convergence gives planners a defensible basis for tiered decision-making, where areas of model agreement can trigger immediate action and divergent areas warrant monitoring or adaptive management.

The authors are careful to note the limits of their framework. The models do not account for ocean warming, freeze-driven shifts between mangrove and marsh dominance, groundwater levels, sediment supply, or the dispersal capacities of individual species, and they should be read as broad-scale screening tools rather than precise predictions. Future work could incorporate focal species, soils data, and higher-resolution elevation analysis. Still, the study demonstrates that integrating climate exposure and geomorphological variation into connectivity analysis can bridge traditional coarse-filter modeling with advanced spatial techniques, producing a transferable template for any coastal region facing the same existential question: not whether the sea will rise, but whether the ecosystems that depend on dry land will have somewhere left to go.

Subject of Research: Modeling coastal-to-inland ecological connectivity and wetland migration corridors under sea-level rise in Florida

Article Title: Sea level rise escape planning for Florida’s coastal ecosystems

Article References: Sea level rise escape planning for Florida’s coastal ecosystems. (n.d.). https://doi.org/10.1007/s44353-025-00064-w

Image Credits: AI Generated

DOI: 10.1007/s44353-025-00064-w

Keywords: sea-level rise, ecological connectivity, coastal wetlands, marsh migration, Florida, SLAMM, Omniscape, conservation planning, topographic diversity, land acquisition, climate adaptation, ghost forests