An Ecological Classification Approach for Hawaiian Stream Reaches: Improving Efforts to Assess Current and Future Conditions

Michigan State University has partnered with the Hawai'i Fish Habitat Partnership (HFHP) and the Institute of Pacific Islands Forestry to develop a landscape-based classification of the ecological potential of Hawaiian stream reaches. Using an existing spatial framework developed for the HFHP, landscape, stream-specific flow data, and state-wide presence absence data for migratory stream species, we developed a classification approach that groups streams into ecological types relevant to stream fauna and measures of faunal vulnerability.  This classification incorporates natural landscape variables such as geology, slope, and elevation and climate variables known to be important in structuring physical and biological characteristics of streams. We used a multi-step process to select influential variables and relied on biological data to ensure ecological meaning.  With streams classified into specific groups, we can characterize the potential of reaches to change with changes in climate on a reach by reach basis. Additionally, we can use regional species-specific data to improve the classification, allowing managers to consider shifts in biological condition in the context of climate change.  These results will be used in support of the 2015 assessment of fish habitats for the HFHP and can be used to inform future climate change assessments of stream habitat.