Identification of Hydrologic Controls on Coastal Spartina patens Marshes and Optimal Hydrological Conditions for Sustainable Mottled Duck Habitat
Mottled ducks rely on the coastal marshes of the Texas Chenier Plain, which are considered among the most critically endangered habitats in the United States. USGS scientists are evaluating what might be contributing to the degradation of high-quality mottled duck habitat to better understand the causes of habitat loss and subsequently mitigate those losses.
The Science Issue and Relevance: Although the Texas Chenier Plain coastal marshes were historically characterized as high-quality habitats for mottled ducks (Anas fulvigula), this critical habitat has been impacted by natural and anthropogenic changes that have resulted in declines. Because of the cumulative and synergistic effects of hydrologic alterations, urbanization, and invasive species encroachment, now this habitat is considered among the most critically endangered habitats in the United States. Specifically, in the McFaddin National Wildlife Refuge (Texas), Spartina patens brackish marshes are rapidly deteriorating, resulting in low quality habitat for mottled ducks and, in some cases, complete habitat loss. Thus, to effectively mitigate the losses of mottled duck habitat, the optimal conditions for vegetation growth need to be clearly identified.
Methodology for Addressing the Issue: Environmental conditions in three healthy and three degraded S. patens brackish marshes will be compared to identify factors contributing to the degradation of mottled duck habitat in McFaddin NWR. Determining these factors is critical to understanding the causes of habitat loss and subsequently mitigating those losses.
Future Steps: To further ensure the sustainability of this critical habitat, it is also necessary to understand what conditions contribute to optimal habitat function. The study will quantify the relationship between elevation, salinity, and plant community composition across elevation and salinity gradients across three marsh types (fresh, brackish, and salt marshes) within the Texas Point NWR. This data will help establish a baseline of hydrologic conditions that will allow managers to optimize plant vegetation growth and mottled duck habitat.
Mottled ducks rely on the coastal marshes of the Texas Chenier Plain, which are considered among the most critically endangered habitats in the United States. USGS scientists are evaluating what might be contributing to the degradation of high-quality mottled duck habitat to better understand the causes of habitat loss and subsequently mitigate those losses.
The Science Issue and Relevance: Although the Texas Chenier Plain coastal marshes were historically characterized as high-quality habitats for mottled ducks (Anas fulvigula), this critical habitat has been impacted by natural and anthropogenic changes that have resulted in declines. Because of the cumulative and synergistic effects of hydrologic alterations, urbanization, and invasive species encroachment, now this habitat is considered among the most critically endangered habitats in the United States. Specifically, in the McFaddin National Wildlife Refuge (Texas), Spartina patens brackish marshes are rapidly deteriorating, resulting in low quality habitat for mottled ducks and, in some cases, complete habitat loss. Thus, to effectively mitigate the losses of mottled duck habitat, the optimal conditions for vegetation growth need to be clearly identified.
Methodology for Addressing the Issue: Environmental conditions in three healthy and three degraded S. patens brackish marshes will be compared to identify factors contributing to the degradation of mottled duck habitat in McFaddin NWR. Determining these factors is critical to understanding the causes of habitat loss and subsequently mitigating those losses.
Future Steps: To further ensure the sustainability of this critical habitat, it is also necessary to understand what conditions contribute to optimal habitat function. The study will quantify the relationship between elevation, salinity, and plant community composition across elevation and salinity gradients across three marsh types (fresh, brackish, and salt marshes) within the Texas Point NWR. This data will help establish a baseline of hydrologic conditions that will allow managers to optimize plant vegetation growth and mottled duck habitat.