Forecasting Climate Change Impacts on Watershed-Based Ecosystem Services in Hawaii:
A Participatory Modeling Approach


Dr. Steven Gray, Researcher, Water Resources Research Center/ Assistant Professor,
Natural Resources and Environmental Management


National Institute for Water Resources, Water Resources Research Institute Program


3/1/2013 - 2/28/2014


Hawaii’s watersheds have been and will continue to be degraded due to anthropogenic climate change, particularly in terms of habitat alteration for native, threatened, and endangered species. Climate change impacts are expected to be prominent on predator/prey dynamics as well; however, direct and indirect ecological effects of habitat change are still largely unknown. We proposed an innovative decision support approach to understanding climate change impacts on the habitat and, abundance of three endangered bird species in one Hawaiian watershed as a case study by integrating regional watershed simulation models (e.g. AnnAGNPS), six selective IPCC scenarios and an expert knowledge-based Fuzzy-Logic Cognitive Mapping (FCM) software called, Mental Modeler ( Hawaiian Stilt, Hawaiian Coot, and Hawaiian Moorhen populations on the island of Kauai were selected to test our modeling framework. The type of decision framework we suggested gave wildlife managers a low cost approximate understanding of the dynamic interaction of climate change, habitat, and wildlife ecology based on pooling available expert knowledge and combing this information with common watershed projections. Enhanced variable-specific restoration efforts were carried out to mitigate and adapt increasing climate change its destructive feedbacks in the watershed. Model results based on IPCC scenarios suggested that increased precipitation will increase Stilt abundance, but decrease Coot and Moorhen abundance. On the other hand, decreasing precipitation have similar effects on all study birds by decreasing Stilt, Coot and Moorhen abundance. Analysis of behavioral life functions show distinctions between the species. Foraging success were increased in general as aquatic plants and animals thrived well except in the case of highest precipitation when they will be washed away. Parental success is positively affected by extreme drought condition. In addition, Breeding/Nesting Success is negatively affected by status-quo /increased precipitation, however reduced rainfall has the opposite affect assuming more rainfall will flood the nests by exceeding the optimal water depth. Sensitivity analysis is done by removing effects of Temperature on some predators (for example, cats and dogs) as gradual temperature is assumed to have little to no effect on them. These produces some significant impacts on abundance.

Through the development of a novel methodology that demonstrated how existing watershed models (DHSVM, N-SPECT, AnnAGNPS) can be integrated with new participatory modeling approaches (FCM, Mental Modeler), this research defines how changes in water quality and quantity will affect important provisioning (e.g., coastal fisheries), regulating (e.g., erosion) and cultural (e.g., recreational and heritage value) services provided by Hawaiian watersheds. Additionally, these model impacts were communicated in terms directly relevant to, and defined by, watershed stakeholders and decision-makers thereby increasing their relevancy to a broader audience, intended to foster more inclusive adaptation planning. By utilizing and refining existing watershed data collected in the Hanalei Bay Watershed on the Island of Kauai as a case study, and partnerships with local watershed managers (Hanalei Watershed Hui), federal government agencies (Army Corps of Engineers, USFWS), and interviews and workshops with relevant Hawaiian community stakeholders (native citizens, coastal fishermen, farmers), this study develops a new formal methodology for understanding how climate change will affect (1) watershed-based ecosystem services and (2) the well-being of watershed stakeholders. The method piloted in this study will help Hanalei watershed stakeholders reduce uncertainty associated with current climate projection while increasing the representation of stakeholder knowledge in watershed planning. Further, the method is expected to be refined and applied in other watersheds throughout the Hawaii Islands, the Pacific and across the US.

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