Understanding Habitat Quality for Preble's Meadow Jumping Mouse: How Survival Responds to Vegetation Structure and Composition

Habitat loss is the primary conservation concern for many rare species; yet, it is unclear what habitat components are vital for the persistence of many rare species. The Preble's meadow jumping mouse Zapus hudsonius preblei (PMJM) was listed as Threatened under the Endangered Species Act because of habitat loss in Colorado and Wyoming. The PMJM is restricted to dense shrub cover and dense herbaceous vegetation along wetland and riverine systems. Although it is well established by researchers that PMJM infrequently leave these habitat types, it is unclear what riparian vegetation structure and composition is important to PMJM survival. We collected and analyzed a 14-y PMJM vegetation-monitoring data set and a PMJM mark-recapture data set to assess the influence of vegetation structure and composition on PMJM annual survival. Using individual, group, and site-specific covariates we estimated survival and evaluated the influence of such covariates on annual survival. Annual survival for PMJM was low (< 10%), increasing with body mass, grass cover, and shrub cover, and decreasing with meadow vole Microtus pennsylvanicus captures. The PMJM use of and occupation of dense riparian habitats may increase individual survival, and likely increases population persistence. Thus, habitat modifications that reduce grass cover and shrub regeneration, such as grazing, suburban development, and development-altered hydrology, will be detrimental to PMJM populations. Given the low annual survival of PMJM, it is important for conserving PMJM populations to minimize disturbances to the vegetation structure, composition, and density, and the hydrologic processes that support them.