As our understanding of complex biotic and abiotic links between emergent marshes and adjacent aquatic habitats increases, restoration approaches must also increase in complexity. We are comparing the success of several emergent marsh restoration techniques by monitoring plant and animal assemblages in a restored brackish wetland near Port Arthur, Texas, USA. We are also conducting a number of experiments to understand how interactions between plants and herbivores are influenced by marsh restoration methods. The study site includes native reference marsh and restored marshes. The restored areas were constructed in spring 2008 using four soil sources: 1) mounds created using soil excavated from adjacent subtidal habitat, 2) mounds excavated then surrounded by dredge fill to decrease surrounding water depth, 3) mounds created from dredge material pumped in directly from a nearby canal, and 4) terraces constructed with soil from an upland dredge disposal site. This research is supported by the Texas General Land Office.

Nutrient enrichment alters seagrass and macroalgal composition, which may alter food quality or composition as well as increase the structural complexity of the plant canopy. Nutrient enrichment in seagrass beds in Florida Bay is associated with increased epifaunal abundance and biomass and shifts in species composition. In collaboration with Dr. Jim Fourqurean at Florida International University (funded by the National Park Service), we are continuing studies exploring the mechanisms driving shifts in faunal abundance, including changes in food resources (epiphyte and seagrass composition) or structural features (complexity of the seagrass-macroalgal infrastructure and its function as a refuge). Future plans include expansion of this project into Galveston Bay.

A Texas Sea Grant project is evaluating the ecological and economic values of tidal brackish and freshwater marshes as wastewater treatment wetlands. In collaboration with Dr. Jae-Young Ko (TAMUG) and Dr. Steven Pennings (University of Houston), we are conducting field surveys that investigate the role of native and exotic vegetation in taking up nutrients from two point sources of anthropogenic nutrients into Armand Bayou (Houston, TX): a sewage treatment facility and a detention basin that filters drainage from a housing subdivision.

Proposed (projects of interest but not yet funded):

Native mangrove invasion into northern Gulf of Mexico salt marshes: the influence of climate change

The northern distribution limit of native red (Rhizophora mangle) and black (Avicennia germinans) mangroves in the Gulf of Mexico is largely determined by winter temperatures. Mild winters over the last ~20 years have caused the expansion of both mangrove species northward along the Texas coast. As climate change brings milder winters, these mangrove populations are likely to continue to expand, replacing salt marshes and modifying coastal ecosystem processes. In particular, the conversion of marsh to mangrove habitat may alter food web interactions and decrease fishery values. Management of coastal wetlands in the context of climate change must consider potential competitive interactions between marsh grasses and mangrove trees.