Integrated species distribution modeling to assess species status and current and future threats for an imperiled amphibian
C. Lane Scher, Brian J. Tornabene, David F. Bradford, J. Tomasz Giermakowski, Caren S. Goldberg, Evan H. Campbell Grant, David A. W. Miller, Riley O. Mummah, Erin Muths, Mason J. Ryan, Brent H. Sigafus, Kenzi M. Stemp, Brian K. Sullivan, Kevin K. Wheeler, Blake R. HossackAbstract
Integrated species distribution models (iSDM) are an innovative approach to inform status assessments and provide estimates and projections to support management and recovery. We combined 13 datasets in an iSDM to estimate the current range of the Arizona Toad ( Anaxyrus microscaphus ), quantify the influence of potential threats across its range, and project changes in abundance and distribution under divergent, mid‐century (2040–2069) climate scenarios. Our model estimated that the Arizona Toad occurs in only 26%–34% of previously defined range boundaries. Covariates representing water availability and environmental moisture were most strongly linked with toad abundance, which peaked in streams with intermediate (~4.1 m 3 /s) flows during spring. Abundance and occurrence were strongly limited by environmental dryness, represented as climatic water deficit, with projected changes in climatic water deficit estimated to decrease range size by up to 22% of our current estimate by the period 2040–2069. Water permanence and the presence of non‐native species were not strongly linked to distribution at the scale of our analysis. Our results highlight the utility of iSDMs in estimating current distributions, identifying threats, and supporting management for taxa, including imperiled species that lack a comprehensive single‐source dataset across their range.