Modeling Coastal Marsh Restoration Benefits in the Northern Gulf of Mexico

Extensive salt marsh restoration is expected in the northern Gulf of Mexico over the next several decades, funded in part by settlements from the 2010 Deepwater Horizon oil spill. Understanding the ecological benefits of restored marshes over time is integral to setting appropriate restoration targets and performance criteria and in determining the restoration area needed to achieve desired restoration goals and offset quantified natural resource injuries. We present a method for quantifying anticipated ecological benefits associated with marsh restoration projects, particularly marsh creation or enhancement through the placement of dredged material, in the northern Gulf of Mexico. Using salt marsh vegetation (percent cover, aboveground biomass, and belowground biomass) and indicator faunal species (periwinkle snails and amphipods) as representative marsh community components, we used resource equivalency analysis (REA) to model projected ecological benefits over time and quantified total net project benefits for a hypothetical marsh creation project in Barataria Bay, Louisiana. Sensitivity analysis of the resulting model suggests that the recovery trajectories for each marsh component were the most important drivers of modeled restoration benefits and that model uncertainty was greatest for marsh fauna, which has limited data availability compared to marsh vegetation and high natural variability. Longer-term monitoring at restored restoration sites and/or targeted monitoring of older restoration projects would reduce variability in the recovery trajectories for the marsh community components examined in this case study and improve the reliability of the REA model for projecting benefits associated with salt marsh restoration.

Status review of Belding's Yellowthroat Geothlypis beldingi, and implications for its conservation

Belding's Yellowthroat (Geothlypis beldingi) inhabits freshwater marshes the length of the state of Baja California Sur. A gap in occurrence from approximately 25°50′N to 24°50′N separates the subspecies goldmani to the north from beldingi to the south. According to BirdLife International's (2000, 2007) population estimates, the most important sites for the species are San Ignacio (537–648 birds) and La Purísima (203–450) in the north and San José del Cabo (219–480) and Punta San Pedro (70) in the south. Half of 12 presumed breeding sites in the north and five of 14 in the south were discovered within the last ten years. The species apparently no longer occurs at one historical site in the south. Since 2000, two records from Guerrero Negro and one from Bahía Tortugas approximately 140 km and > 200 km respectively northwest of the known breeding range demonstrate the species' dispersal ability. Belding's Yellowthroat is of utmost conservation concern, but the most recent conservation summaries exaggerated the species' plight, in particular by under-appreciating the bird's capacity for long-range dispersal and the ability of marsh habitat to regenerate quickly. Formal studies of the species should be undertaken and marsh creation should be incorporated in the state's development plans. Previous calls for reintroduction efforts should not be heeded, at least for the time being.