Anticipating future trajectories of global drivers such as climate and land-use change and their consequences for ecosystem services remains challenging. Scenarios are stories about plausible futures, and can be integrated with simulation models to explore quantitatively how the future might unfold. However, few scenario studies have integrated a wide range of drivers with spatially explicit, process-based ecosystem models, and none have explored the fine-scale spatial-temporal dynamics of a portfolio of ecosystem services. We evaluated future prospects of 9 ecosystem services from 2010 to 2070 in the 1300-km2Yahara Watershed (Wisconsin, USA) for four provocative, contrasting future scenarios. We asked: (1) How does ecosystem service supply vary among alternative scenarios? (2) Where on the landscape is the provision of ecosystem services most vulnerable to future changes? (3) Are tradeoffs and synergies among ecosystem services consistent across different future scenarios? Scenarios were developed with structured inputs from local stakeholders, and translated into quantitative drivers (climate, land cover, population, and management) that were input into four linked biophysical simulation models (Agro-IBIS, MODFLOW, THMB, and the Yahara Water Quality Model) to quantify indicators of ecosystem services at 220×220m resolution.
Different sets of ecosystem services were prioritized under alternative scenarios, and no single scenario was best for all services. Relative to 2010, crop production in 2070 was maintained in one scenario but declined 63% to 88% in others. Pasture production ranged from a 70% decline to a 280% increase among scenarios. Freshwater supply was sustained in only one scenario, whereas surface- and ground-water quality improved in nearly all scenarios. Soil retention and flood regulation improved in one scenario but declined or increased only slightly in others. Soil carbon storage changed minimally in all scenarios (from 8% decline to 3% increase). Spatially, locations of greatest decline in service supply (i.e., greatest vulnerability) were heterogeneous, and patterns differed by service and among scenarios. Our results revealed consistent tradeoffs between crop production and water quality; however, such tradeoffs could be mitigated by improved farming technology and nutrient management. We also found consistent synergies between soil retention and surface-water quality, but this synergy was undermined by strong land-use legacies of phosphorus accumulation in soils. Alternative social choices can produce contrasting future outcomes and alter interactions among some ecosystem services.