Transcript Slide 1
Designing Wetland Conservation Strategies under Climate Change Jiayi Li, Elizabeth Marshall, James Shortle, Richard Ready, Carl Hershner Department of Agricultural Economics and Rural Sociology Virginia Institute of Marine Sciences Introduction Cellular Automaton (CA) Model Wetland conservation is a major environmental concern in the Chesapeake Bay region. Substantial losses due to land development and other factors have had profound impacts on the Bay’s aquatic resources. Major wetland functions include: habitat provision, water quality improvement, flood protection, bank stabilization, and sediment control. Current conservation efforts fail to account for the impacts of climate change on sea level, which can affect the success of conservation efforts. CA examines changes taking place purely as a function of what happens in the immediate vicinity of any particular cell. The land use data is mapped into cells, as shown in Figure 5. We identify four major drivers that influence the development possibility for each undeveloped land cell. We assign different weight sets to the four major drivers to reflect three different future land use scenarios: compact development, dispersed development, and nodal development. Immediate vicinity land use type Distance to shoreline Fig 1: Function: Water Quality Fig 2: Function: Wildlife Habitat Source: National Image Library Source: National Image Library Distance to primary roads Distance to population centers Fig 5: CA Model Illustration Objective This study develops a methodology for evaluating public wetlands conservation investments that takes climate change into account. We demonstrate the methodology for the Elizabeth River watershed in Virginia under plausible sea-level rise and land use scenarios. We consider a 30-year time period Discrete Stochastic Sequential Programming (DSSP) We consider two types of uncertain events that may affect decisions in our DSSP model. - Acquisition of new information about high or low sea-level rise (SLR). - Knowing the likelihood that an undeveloped land parcel would become developed. Figure 6 shows how these uncertain events are included in a 2-stage decision process. Fig 3: Elizabeth River Watershed, Virginia T=1 T=2 High SLR (P0) Methods Cost-effective analysis is used to compare two wetland conservations strategies: Keep Sell Buy - Strategy 1: Preserve high-elevation undeveloped land adjacent to existing wetland. Low SLR (1- P0) Keep Sell Fig 4: Wetland Migration (Titus, 1990) Decision High SLR/Undeveloped (P1) Not Buy Not Buy - Strategy 2: Relocate wetland to suitable areas where land prices are low. The cellular automaton (CA) model is used to construct a development vulnerability index and to project land use changes for the study area. The discrete stochastic sequential programming (DSSP) technique is used to minimize the costs of implementing each wetland conservation strategy. Buy Low SLR/Undeveloped (P2) Buy Not Buy High SLR/Developed (P3) Low SLR/Developed (1-P1-P2-P3) Fig 6: Two stage decision process Acknowledgement: 1. Support is provided by the Global Change Research Program, Office of Research and Development, U.S. Environmental Protection Agency (Cooperative Agreement R-83053301). 2. Steve Graham, Penn State and Tamia Rudnicky, Virginia Institute of Marine Science (VIMS) provided GIS data and analysis assistance. 3. Marcia Bermen, Walter Priest and Dan Schatt, VIMS gave valuable suggestions.