Evaluating ecosystem-based management alternatives for the Puget Sound, U.S.A. social-ecological system using qualitative watershed models

Population growth and the associated transformation of landscapes is a major management challenge for coastal ecosystems. Coastal conservation should be guided by social, cultural, economic, ecological objectives, but integrative decision support tools appropriate complex ecosystems remain underutilized. Evaluating alternative policies objectives that span interconnected terrestrial, freshwater, estuarine habitats along coastlines limited lack quantitative available data. We employed qualitative network models (QNMs) to evaluate multi-benefit outcomes potential interventions address population development using case study Puget Sound – large, urbanized fjord-type estuary in Washington, U.S.A. With input from regional scientists stakeholders, we developed base conceptual model links among human stressors ecosystem components across terrestrial-freshwater-estuarine gradient generalized watershed. simulated scenarios representing strategies accommodating growth, namely new outside urban centers versus redevelopment (densification) within centers, characterized responses multiple recovery each scenario. Of scenarios, reducing stormwater runoff increasing green infrastructure provided most favorable outcomes. On rural lands, limiting existing transportation corridors iincreasing floodplain riparian habitat extent concomitant with produced similar Moderate levels coordinated on both lands had more compared either moderate intervention applied separately. This demonstrates value cross-habitat evaluations possible futures ecosystem-based systems.