Assessment of Changing Ecosystem Services Provided by Marsh Habitat in the Galveston Bay Region Final Report to the Gulf of Mexico Foundation and the Habitat Conservation and Restoration Team of the Gulf of Mexico Alliance D. Yoskowitz, C. Carollo, J. Beseres-Pollack, K. Welder, C. Santos, and J. Francis June 2012 Assessment of Changing Ecosystem Services Provided by Marsh Habitat in the Galveston Bay Region Table of Contents EXECUTIVE SUMMARY ................................................................................................................................. 2 Introduction .................................................................................................................................................. 3 Sea Level Affecting Marshes Model 6 ........................................................................................................... 4 Ecological characterization of selected habitats........................................................................................... 5 Fresh marsh ................................................................................................................................................... 5 Salt marsh ..................................................................................................................................................... 8 Swamps ......................................................................................................................................................... 9 Ecosystem services...................................................................................................................................... 10 Disturbance regulation or Hazard mitigation ............................................................................................. 11 Recreation ................................................................................................................................................... 11 Food ............................................................................................................................................................ 12 Aesthetics .................................................................................................................................................... 12 Nutrient cycling ........................................................................................................................................... 12 Soil retention ............................................................................................................................................... 12 Waste regulation ........................................................................................................................................ 13 Hydrological balance or Water regulation .................................................................................................. 13 Habitat change under selected sea level rise scenarios ............................................................................. 13 Ecosystem services valuation...................................................................................................................... 22 Methodology ............................................................................................................................................... 22 Results ......................................................................................................................................................... 24 Heat map demonstrating differences in the demand for ecosystem services ........................................... 29 Limitations .................................................................................................................................................. 38 References .................................................................................................................................................. 39 Appendix A ................................................................................................................................................. 45 Suggested citation: Yoskowitz, D., C. Carollo, J. Beseres-Pollack, K. Welder, C. Santos, and J. Francis. (2012). Assessment of Changing Ecosystem Services Provided by Marsh Habitat in the Galveston Bay Region. Harte Research Institute. June. 75 pages. 1 Harte Research Institute EXECUTIVE SUMMARY The goal of this study was to identify the potential changes in ecosystem services values provided by wetland habitats in the Galveston Bay region. Built exclusively upon the output produced during the Sea Level Affecting Marshes Model 6 (SLAMM 6) exercise for Galveston Bay, TX, the study shows that the selected habitats, fresh marsh, salt marsh, and swamp, present a steady decline in time under three sea level rise scenarios (A1B mean = 0.39m; A1Bmax = 0.69m; and 1.5m). Fresh marsh is the habitat that is projected to undergo the biggest changes under all sea level rise scenarios, with the loss of about 21% of its extent between 2009 and 2100 under the A1Bmax scenario. This trend is due to the fact that fresh marsh is displaced by salt marsh and other habitats and has insufficient time and/or space to migrate landward. The percentages of change for salt marsh and swamp are less prominent, but still significant with about 12% and 16% loss, respectively, between 2009 and 2100 under the A1Bmax sea level rise scenario. This trend is also shown in the values of ecosystem services provided by these habitats. An ordinary least squares regression model was used to calculate the monetary value of selected ecosystem services provided by each chosen habitat in 2009 (initial condition) and in 2050 and 2100 under the A1B max (0.69m) sea level rise scenario. This method is called value transfer and specifically involves transferring meta-regression analysis functions. Meta-regression analysis combines estimates from multiple original studies and applies them to the policy site. This analysis shows that, under the A1Bmax sea level rise scenario, the value for the total area of fresh marsh including all ecosystem services (nutrient cycling, disturbance regulation, food, aesthetics, recreation, and water regulation) presents significant monetary losses, $87.7 million per year from 2009 to 2100. Looking at individual services for fresh marsh, disturbance regulation has major impact and shows a significant loss in total area values, $27.4 million from 2009 to 2100, with sea level rise. Under the same scenario, from initial condition to 2100, $13.7 million per year is lost in ecosystem services (disturbance regulation, recreation, food, aesthetics, nutrient cycling, and soil retention) provided by salt marsh. Looking at individual services, salt marsh follows the same pattern as fresh marsh; disturbance regulation shows the major economic impact with $4.3 million per year lost from 2009 to 2100, followed by recreation with $3.5 million per year lost from 2009 to 2100. Due to a lack of original studies valuing the ecosystem services provided by swamps, it was not possible to conduct a meta-regression analysis to calculate the change in ecosystem services values provided by this habitat; instead, point estimates using the average per hectare per year ecosystem services values were used. Under the sea level rise A1B max scenario, there is a cumulative economic loss of ecosystem services (recreation, waste regulation, disturbance regulation, food, and aesthetics) values provided by swamps of about $12 million, from current condition to 2100. The ecosystem services value estimates provided here are only a small portion of what can be lost due to the decrease in habitat area and the loss of its associated services. These results may stress the importance of not only protecting built infrastructure, but also natural resources, such as habitat, from sea level rise. 2 Assessment of Changing Ecosystem Services Provided by Marsh Habitat in the Galveston Bay Region I. Introduction Sea level rise poses potential threats to not only manmade or built infrastructure but also to natural assets that provide numerous ecosystem services that impact human well-being. As relative sea level changes it is likely that the quality and distribution of our natural assets will change as well. For example, wetland losses or marked vegetation changes can result from accelerated sea level rise (Warren and Niering 1993, Craft et al. 2009) and tidal marshes are highly susceptible to sea level rise (Moorhead and Brinson 1995, Park et al. 1991). These bio-physical alterations will lead to changes in ecosystem services (ES). An understanding of these changes and their impacts is critical to managing these habitats effectively. For the purpose of this study, the following definition of ecosystem services (ES) is used: ecosystem services are the contributions from Gulf of Mexico marine and coastal ecosystems that support, sustain, and enrich human life (Yoskowitz et al. 2010). In recent years, ES have attracted a substantial amount of discussion and research, but examples where ES concepts have been applied to real-world policies and decisions are rare. Yet, there is today a greater call for the incorporation of ES to inform the decision making process than at any other time. While there is a call to action there is also a great need to build the capacity to achieve these goals. ES analysis is highly multidisciplinary, involving ecologists, physical scientists, modelers, economists, and social scientists. Large volumes of research