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Alternative futures analysis can inform community decisions regarding land and water use. We conducted an alternative futures analysis in the Willamette River Basin in western Oregon. Based on detailed input from local stakeholders, three alternative future landscapes for the year 2050 were created and compared to present‐day (circa 1990) and historical (pre‐EuroAmerican settlement) landscapes. We evaluated the likely effects of these landscape changes on four endpoints: water availability, Willamette River, stream condition, and terrestrial wildlife. All three futures assume a doubling of the 1990 human population by 2050. The Plan Trend 2050 scenario assumes current policies and trends continue. Because Oregon has several conservation‐oriented policies in place, landscape changes and projected environmental effects associated with this scenario were surprisingly small (most ≤10% change relative to 1990). The scenario did, however, engender a debate among stakeholders about the reasonableness of assuming that existing policies would be implemented exactly as written if no further policy actions were taken. The Development 2050 scenario reflects a loosening of current policies, more market‐oriented approach, as proposed by some stakeholders. Estimated effects of this scenario include loss of 24% of prime farmland; 39% more wildlife species would lose habitat than gain habitat relative to the 1990 landscape. Projected effects on aquatic biota were less severe, primarily because many of the land use changes involved conversion of agricultural lands into urban or rural development, both of which adversely impact streams. Finally, Conservation 2050 assumes that ecosystem protection and restoration are given higher priority, although still within the bounds of what stakeholders considered plausible. In response, most ecological indicators (both terrestrial and aquatic) recovered 20–70% of the losses sustained since EuroAmerican settlement. The one exception is water availability. Water consumed for out‐of‐stream uses increased under all three future scenarios (by 40–60%), with accompanying decreases in stream flow. Although the conservation measures incorporated into Conservation 2050 moderated the increase in consumption, they were not sufficient to reverse the trend. Results from these analyses have been actively discussed by stakeholder groups charged with developing a vision for the basin's future and a basin‐wide restoration strategy.

Spatially explicit landscape analyses are a central activity in research on the relationships between people and changes in natural systems. Using geographical information systems and related tools, the Pacific Northwest Ecosystem Research Consortium depicted historical (pre‐EuroAmerican settlement, circa 1850), current (circa 1990), and three alternative future (circa 2050) landscapes for western Oregon's Willamette River Basin. These depictions were used to better understand and anticipate trajectories of change in human occupancy and natural resource condition. During a 30‐month period, we worked with lay and professional citizen groups to create, map, and refine a set of value‐based assumptions about future policy in three scenarios concerning land and water use. The Plan Trend 2050 scenario represents the expected future landscape in 2050 if current policies are implemented as written and recent trends continue. Development 2050 reflects a loosening of current policies, to allow freer rein to market forces across all components of the landscape, but still within the range of what citizen stakeholders considered plausible. Conservation 2050 places greater emphasis on ecosystem protection and restoration, still reflecting a plausible balance among ecological, social, and economic considerations as defined by the stakeholders. For the Conservation scenario, natural resource managers and scientists provided estimates for the area of key habitats required to sustain, in perpetuity, the array of dependent species. Spatially explicit analyses identified locations biophysically suited to meet the area targets. These locations, titled the Conservation and Restoration Opportunity Areas, were mapped and then reviewed by a series of groups regarding the political plausibility of conserving or restoring them to the indicated vegetation types. The three alternative 2050 futures, as well as the 1850 past conditions, were then evaluated by an array of evaluation models described by others in this issue. The Conservation and Restoration Opportunities map from the Conservation 2050 scenario has been adopted by the group charged with salmon recovery in the basin as the centerpiece of its restoration strategy.

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Increasingly, models (and modelers) are being asked to address the interactions between human influences, ecological processes, and landscape dynamics that impact many diverse aspects of managing complex coupled human and natural systems. These systems may be profoundly influenced by human decisions at multiple spatial and temporal scales, and the limitations of traditional process-level ecosystems modeling approaches for representing the richness of factors shaping landscape dynamics in these coupled systems has resulted in the need for new analysis approaches. Additionally, new tools in the areas of spatial data management and analysis, multicriteria decision-making, individual-based modeling, and complexity science have all begun to impact how we approach modeling these systems. The term "biocomplexity" has emerged a descriptor of the rich patterns of interactions and behaviors in human and natural systems, and the challenges of analyzing biocomplex behavior is resulting in a convergence of approaches leading to new ways of understanding these systems. Important questions related to system vulnerability and resilience, adaptation, feedback processing, cycling, nonlinearities and other complex behaviors are being addressed using models employing new representational approaches to analysis. An emerging application area is alternative futures analyses, the study of how complex coupled human/natural systems dynamically respond to varying management strategies and driving forces. This methodology is increasingly being used to inform decision makers about the implications of policy alternatives related to land and water management, expressed in terms related to human valuations of the landscape. Trajectories of change become important indicators of system sustainability, and models that can provide insight into factors controlling these trajectories are rapidly becoming essential tools for planning. The complexity inherent in these systems challenges the modeling community to provide tools that capture sufficiently the richness of human and ecosystem processes and interactions in ways that are computationally tractable and understandable. We examine one such tool, Evoland, which uses an actor-based approach to conduct alternative futures analyses in the Willamette Basin, Oregon. Actor-based approaches, spatially-explicit landscape representations, and complexity science are providing new ways to effectively model, and ultimately to understand, these systems.