By: Bryan Watts
The eastern black rail continues its decline along the Atlantic Coast. Birds are being systematically excluded from their traditional salt marshes by advancing sea-level rise. The status assessment conducted in 2016 by CCB revealed a 650-km range contraction from Cape Cod south to New Jersey. For all intents and purposes, the range contraction has continued and over the intervening period has extended an additional 600 km down to South Carolina. The only safety net that is holding the line in South Carolina is that birds are being supported within nontidal or tidally suppressed impoundments. Although we continue to hope that birds displaced from tidal marshes from New Jersey through North Carolina will take root within nontidal habitats and grow, current evidence for this shift is not compelling.
Black rail conservation biologists are squarely focused on nontidal habitats and are frantically working on developing ways to facilitate the population’s inevitable transition from salt to freshwater wetlands. Although we have historic records of black rails within freshwater wetlands along the Atlantic Slope, we know very little about the habitat conditions they used. Traditional restoration whether of historic homes or antique cars begins with a blueprint, a list of parts or at least an image of what the final product should look like. With eastern black rails, we have only an incomplete list of requirements to work with and very little time to tinker.
In early March 2021, a CCB team traveled to South and Central Florida to take topographic, hydrologic and vegetation measurements within a series of sites that were either occupied or not occupied by black rails. Black rails appear to require topographic diversity that provides a mosaic of wet and dry areas, so the team used an optical survey level to measure the bones of the land and will develop metrics to reflect several dimensions of topographic relief. Black rails occupy the dry end of the wetland spectrum and so the team examined the variation in water depth and soil moisture. Black rails require dense overhead vegetation for cover, so the team also collected vegetation structure and composition data. The effort has been focused on identifying useful metrics that may allow us to predict which nontidal wetlands black rails use and to identify places where the landscape structure will allow us to create or manage new black rail habitat.
The CCB team also traveled to Central Florida to conduct preliminary surveys of the region’s historic ranchlands. The surveys were part of a USDA effort to integrate black rails into working lands. Central Florida boasts 3,000,000 acres of ranchland supporting 600,000 head of beef cattle. Many of these ranches have been run by families for several generations and are part of the Central Florida culture. The rangelands do support many wetland patches that are important to the bird community. A number of open questions remain about this region with respect to the future of black rails. Is there a place for black rails within the Florida ranchlands? Can we fit black rail management into ranching operations? How and where may we be able to attract black rails onto working ranches? Over the next couple of months we will be evaluating what we have learned during the trip to Florida. Stay tuned.