Habitat Use of the Rocky Mountain Water Shrew in the White Mountains, Arizona

Abstract

Abstract The population of Rocky Mountain water shrew Sorex navigator occurring in the White Mountains, Arizona, is isolated, genetically divergent, and of conservation concern. However, little is known about its distribution and habitat use due to difficulty capturing animals during previous surveys. The objectives of this study were to report captures of S. navigator that occurred during a survey for the New Mexico jumping mouse Zapus luteus luteus that expand its known distribution, evaluate habitat of capture sites, report natural history observations, and describe methods for capturing S. navigator. We captured 17 S. navigator at six sites, making this the most successful survey for this population. The records included two new sites and confirmation of the persistence of two historical populations considered extirpated. At the landscape scale, elevation was the best predictor of sites for capture of S. navigator. We captured Rocky Mountain water shrews on small cold-water streams and seeps on saturated soil with high vertical cover of herbaceous plants primarily consisting of sedges Carex. Sherman live traps were ideal for capturing S. navigator, if set appropriately. Given the population's restricted distribution, fragile habitat, and ongoing threats, conservation measures may be warranted.