The Coastal Plain as a Large Wetland: Assessment of Water Connectivity Across the Norte Fluminense Coastal Plain, Brazil

Coastal plains are low-lying sedimentary landscapes with terraces parallel to the sea that support numerous wetlands. Human activity limits our ability to recognize them as vast coastal wetlands with macrohabitats linked by water and biodiversity. Our hypothesis is that surface water connects across the coastal plain because of morphology, hydrology, climate, and human activity. The purpose of this study is to investigate surface water connections across the Norte Fluminense coastal plain using hydro-morphometric characterization, as well as the interaction between long-term water surface, climate parameters, and human management. We used remote sensing analysis, morphologic and hydrologic indices, rainfall and evaporation data from models and meteorologic stations, and information about human management to describe the water connectivity across the coastal plain. The coastal plain has a larger water surface area, number of flooded patches and short average distance between flooded patches during the rainy years, suggesting surface water connectivity across the coastal plain. There is a strong correlation between the flooded area and rainfall and evapotranspiration. Human management can either maintain the water connections (protected areas, for example) or disrupt them (opening lagoon sandbars). This coastal plain should be analyzed as a connected catchment-wetland system, since our hydro-geomorphological classification suggests hydrological and ecological connection when compared to other wetlands. Therefore, our results demonstrate that, depending on hydrological parameters and connectivity, coastal plains can be categorized as large coastal wetland; however, other factors like biodiversity must also be considered.