title: Effects of changing climate on aquatic habitat and connectivity for remnant populations of a wide-ranging frog species in an arid landscape.
abstract: Amphibian species persisting in isolated streams and wetlands in desert environments can be susceptible to low connectivity, genetic isolation, and climate changes. We evaluated the past (1900-1930), recent (1981-2010), and future (2071-2100) climate suitability of the arid Great Basin (USA) for the Columbia spotted frog (Rana luteiventris) and assessed whether changes in surface water may affect connectivity for remaining populations. We developed a predictive model of current climate suitability and used it to predict the historic and future distribution of suitable climates. We then modeled changes in surface water availability at each time period. Finally, we quantified connectivity among existing populations on the basis of hydrology and correlated it with interpopulation genetic distance. We found that the area of the Great Basin with suitable climate conditions has declined by approximately 49% over the last century and will likely continue to decline under future climate scenarios. Climate conditions at currently occupied locations have been relatively stable over the last century, which may explain persistence at these sites. However, future climates at these currently occupied locations are predicted to become warmer throughout the year and drier during the frog's activity period (May - September). Fall and winter precipitation may increase, but as rain instead of snow. Earlier runoff and lower summer base flows may reduce connectivity between neighboring populations, which is already limited. Many of these changes could have negative effects on remaining populations over the next 50-80 years, but milder winters, longer growing seasons, and wetter falls might positively affect survival and dispersal. Collectively, however, seasonal shifts in temperature, precipitation, and stream flow patterns could reduce habitat suitability and connectivity for frogs and possibly other aquatic species inhabiting streams in this arid region.
authors.affiliation: U.S. Geological Survey Forest and Rangeland Ecosystem Science Center 970 Lusk Street Boise Idaho 83706.
authors.forename: David S
authors.initials: DS
authors.lastname: Pilliod
authors.affiliation: U.S. Geological Survey Forest and Rangeland Ecosystem Science Center 970 Lusk Street Boise Idaho 83706.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Arkle
authors.affiliation: Department of Biology California State University Northridge California 91330.
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Robertson
authors.affiliation: Department of Ecosystem Science and Management Program in Ecology University of Wyoming Laramie Wyoming 82071.
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Murphy
authors.affiliation: Department of Biology Graduate Degree Program in Ecology Colorado State University Fort Collins Colorado 80523.
authors.forename: W Chris
authors.initials: WC
authors.lastname: Funk
keywords: Amphibian; Columbia spotted frog; Great Basin; Rana luteiventris; climate change; gene flow; habitat fragmentation; isolation; resistance surface