ESTUARINE MARSH AND TIDAL-FLAT CHANGE IN RESPONSE TO RELATIVE SEA-LEVEL RISE, CENTRAL TEXAS GULF COAST

Estuarine marshes and tidal flats are critical components of the Texas coastal wetland ecosystem. Biological and chemical productivity in marshes and flats is essential to coastal flora and fauna. In a series of status and trends studies of wetland habitats along the central Texas coast, we analyzed changes in wetland and aquatic habitats between the mid-1950’s and 2009. Studies of this nature provide useful information for habitat management, thus ensuring marsh protection and preservation. This study focuses on historical changes in estuarine marsh and tidal-flat habitats at several locations along the central Texas coast. Wetland habitats on the Texas coast are dominated by estuarine emergent wetlands. The southernmost wetlands contain primarily wind-tidal and algal-flat habitats. Since the mid-1950’s there has been a net gain (~15%) of estuarine marsh habitat and a net loss (~57%) of tidal-flat habitat in central coast wetlands. One of the main factors affecting wetland systems on the Texas coast is the rate of relative sea-level rise (RSLR). In some locations, human-induced subsidence and faulting have accelerated rates of RSLR, contributing to marsh loss. However, overall rates of RSLR along the central coast are relatively low, compared with those of the upper coast, and marsh area has remained stable or has expanded over time. The long-term decline in the extent of tidal-flat habitat in central coastal wetlands is consistent with trends found throughout the Texas coastal wetland system. As sea level rises, flats are replaced by other habitats.