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Scenario Analysis: Evaluating Biodiversity Response to Forecasted Land-Use Change in the San Pedro River Basin (U.S.-Mexico)
Citation:
Kepner, W., K. Boykin, A. Neale, AND K. Gergely. Scenario Analysis: Evaluating Biodiversity Response to Forecasted Land-Use Change in the San Pedro River Basin (U.S.-Mexico). A Community on Ecosystem Services (ACES): Linking Science, Practice, and Decision, Washington, DC, December 08 - 12, 2014.
Impact/Purpose:
Because the San Pedro Watershed encompasses so much area, and a significant portion is undevelopable, the changes that are occurring in developable subwatersheds may need to be examined at a larger scale to determine if hydrologic impacts would be unacceptable that might otherwise be captured if the impacts were occurring basin-wide and triggering a larger, unacceptable impact at the watershed outlet.
Description:
Envisioning and evaluating future scenarios has emerged as a critical component of both science and social decision-making. The ability to assess, report, map, and forecast the life support functions of ecosystems is absolutely critical to our capacity to make informed decisions to maintain the sustainable nature of our environment now and into the future. Evaluating trade-offs in terms of ecosystem services and human well-being provides an intuitive and comprehensive way to assess the broad implications of our decisions and to help shape policies that enhance environmental and social sustainability. In answer to this challenge, the U.S. Environmental Protection Agency (EPA) has created a partnership with other Federal agencies, academic institutions, and Non-Governmental Organizations to develop the EnviroAtlas, an online national Decision Support Tool that allows users to view and analyze the geographical description of the supply and demand for ecosystem services, as well as the drivers of change. As part of the EnviroAtlas, an approach has been developed to quantify and map various metrics within an ecosystem services framework that are representative of vital functions and support services such as A) Biodiversity Conservation; B) Food, Fiber, and Materials; and C) Recreation, Culture, and Aesthetics. This approach is being further tested in regard to future long term land-use change scenarios to characterize ecological impact from future urban growth. Future growth is represented by housing density maps generated in decadal intervals from 2010 to 2100 derived from the EPA Integrated Climate and Land-Use Scenarios (ICLUS) national database. ICLUS developed future housing density maps by adapting the Intergovernmental Panel on Climate Change- Special Report on Emissions Scenarios social, economic, and demographic storylines to the conterminous United States. The first level of futures testing has been conducted in the San Pedro River along the U.S.-Mexico border, a watershed that is world renown for its species richness and an area where economics and population growth present significant challenges to environmental decision-making related to sustainable future conditions. Selected metrics, e.g. harvestable species, threatened and endangered species, and watchable wildlife, were composed from 452 deductive terrestrial vertebrate models derived from the U.S. Geological Survey Gap Analysis Program data and utilized to examine ICLUS change scenarios for urban and residential development across the watershed. The A2 Scenario is characterized by the highest human population growth, greatest land conversion, and highest domestic migration resulting in new population centers and typically represents the greatest loss in the metrics examined. Although natural area was lost under all ICLUS scenarios throughout the 90-year study timeline and geographic patterns varied among metrics across the study area, the approach appears to demonstrate great promise for examining long-term change and make predictive inferences about the future over broad geographical areas such as watersheds.