Hydroclimatic Variables for Predicting Riparian Habitat Suitability
Brad Butterfield1,2, Emily Palmquist2,3
1Center for Ecosystem Science and Society (ECOSS), Northern Arizona University, Flagstaff, AZ, USA; Bradley.Butterfield@nau.edu
2Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
3U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, AZ, USA; epalmquist@usgs.gov
Identifying target communities for restoration requires an understanding of the underlying hydrologic and climatic factors that determine habitat suitability. Hydrology and climate can have strong interactive effects on plant performance and population growth, where river flows can ameliorate or exacerbate stressors related to evaporative demand or precipitation. In order to assess the importance of these interactions in determining riparian habitat suitability, we quantified a suite of “hydroclimatic” variables that characterize climate conditions during periods of high and low flows, and likewise the flow conditions that typify climatically stressful or benign parts of the year. We developed ecological niche models for a suite of common woody riparian plant species, as well as riparian LANDFIRE Existing Vegetation Types, across the Western US. We found that incorporating hydroclimatic variables significantly improved model fit over models that only included standard bioclimatic and hydrologic variables. We discuss the implications for riparian restoration, and flow management in the context of compensating for climatic stress with environmental flows.