Spatial and Statistical Analysis of the Causes of Saltmarsh Loss Along the Texas Coast

In the state of Texas, cities and counties located along the coastline have all experienced an increase in population due to its navigable waterways and natural resources. Policy makers are faced with a difficult task to plan for the growth of urban development while using natural resources in a sustainable fashion. Despite efforts to protect valuable natural areas such as marshes, wetland loss continues to occur. In a study conducted in 2015 by Armitage et al., it was recently discovered that saltmarsh areas on the Texas coastline decreased by 77.8 km^2 from 1990-2010 within the Coastal Zone Management (CZM) boundary. When a formerly extensive area of salt marshes has been reduced by conversion to agricultural land, urban development or for industrial use and port facilities it can become quite a significant problem (Boorman,1999). Saltmarshes are given great value due to their ability to absorb impacts from storms, provide wildlife habitat, and provide social and economic benefits. It then becomes critical that analysis be conducted to identify the major causes of wetland loss along the Texas coastline. This thesis aims to understand the major drivers of saltmarsh change throughout the 20-year time frame. Using the change in saltmarsh area for 1990-2010 as the dependent variable and watersheds as the unit of analysis, a regression model was estimated to evaluate drivers of saltmarsh change. Results indicate that if more saltmarsh area was present prior to 2010, then the change would decrease significantly. Additionally, Section 404 permits granted by the U.S. Army Corps of Engineers that permitted the alteration of wetlands indicated that as more permits were distributed, the change that occurred from 1990-2010 increased significantly. Change in population proved quite the opposite. As population change occurred, it decreased the amount of area change in saltmarshes. Similarly, sea level rise also demonstrated to decrease the amount of change exhibited by saltmarsh area. Discussion of the results for all four statistically significant variables reveal that more studies will need to be conducted to further understand their effects on saltmarshes