Daytime Amphibian Surveys in Three Protected Areas in the Western Great Lakes

We performed pilot monitoring of amphibian populations at Apostle Islands National Lakeshore (APIS) in 2006, Pictured Rocks NationalLakeshore (PIRO) in 2007, and Sleeping Bear Dunes National Lakeshore (SLBE ) in both 2006 and 2007. We performed daytime surveys (using multiple methods) at numerous sites in each of the three parks. We detected 10 amphibian and two reptilian species at APIS, nine amphibian and four reptilian species at SLBE , and nine amphibian and one reptilian species at PIRO. No one daytime survey technique appeared to be superior to any other. Our work resulted in two new species records (Gray Treefrog and Green Frog) for Basswood Island at APIS

Daytime Amphibian Surveys in Three Protected Areas in the Western Great Lakes

We performed pilot monitoring of amphibian populations at Apostle Islands National Lakeshore (APIS) in 2006, Pictured Rocks NationalLakeshore (PIRO) in 2007, and Sleeping Bear Dunes National Lakeshore (SLBE ) in both 2006 and 2007. We performed daytime surveys (using multiple methods) at numerous sites in each of the three parks. We detected 10 amphibian and two reptilian species at APIS, nine amphibian and four reptilian species at SLBE , and nine amphibian and one reptilian species at PIRO. No one daytime survey technique appeared to be superior to any other. Our work resulted in two new species records (Gray Treefrog and Green Frog) for Basswood Island at APIS

FACING A CHANGING WORLD: THERMAL PHYSIOLOGY OF AMERICAN PIKAS (OCHOTONA PRINCEPS)

American pikas (Ochotona princeps) are of concern with respect to warming montane temperatures; however, little information exists regarding their physiological ability to adapt to warming temperatures. Previous studies have shown that pikas have high metabolism and low thermal conductance, which allow survival during cold winters. It has been hypothesized that these characteristics may be detrimental, given the recent warming trends observed in montane ecosystems. We examined resting metabolic rate, surface activity, and den and ambient temperatures (Ta) of pikas in late summer (August 2011 and 2012) at 2 locations in the Rocky Mountains. Resting metabolic rate was calculated to be 2.02 mL O2 ⋅ g−1h−1, with a lower critical temperature (LCT) of 28.1 –+ 0.2 °C. No upper critical temperature (UCT) could be determined from our data; therefore, the estimated thermoneutral zone (TNZ) was 28.1 °C to at least 35.0 °C (upper experimental temperature). Pikas in this study showed the same bimodal above-talus activity patterns reported in previous studies. Den temperatures in Colorado were correlated with, but consistently lower than, current ambient temperatures. Wyoming den temperatures showed a weak correlation with Ta 20 min prior to the current den temperature. This study is one of few to present data on the physiological response pikas may have to current warming conditions, and the first to perform metabolic measurements in situ. Our data support conclusions of previous studies, specifically MacArthur and Wang (1973, 1974) and Smith (1974), which indicated American pikas may not have the physiological ability to cope with high Ta. Our results also highlight the importance of shaded regions below the talus rocks for behavioral thermoregulation by pikas. RESUMEN.—La pica americana (Ochotona princeps) es una especie considerada de preocupación debido al aumento de la temperatura en las montañas. Sin embargo, existe poca información relacionada a su capacidad fisiológica para adaptarse a temperaturas más cálidas. Estudios previos han mostrado que las picas tienen un metabolismo alto y una conductividad térmica baja, lo que les permite sobrevivir en los inviernos fríos. Se ha planteado la hipótesis de que estas características pueden ser perjudiciales, dadas a las tendencias recientes de calentamiento en los ecosistemas de montaña. Examinamos la tasa metabólica en reposo, la actividad superficial y la temperatura en las madrigueras y la temperatura ambiente (Ta) de las picas a finales del verano (agosto de 2011 y 2012) en 2 áreas de las Montañas Rocosas. Calculamos que la tasa metabólica en reposo sería 2.02 mL O2 ⋅ g−1h−1, con una temperatura crítica inferior (LCT) de 28.1 –+ 0.2 °C. No pudimos determinar la temperatura crítica superior (UCT) a partir de nuestros datos; por lo tanto, la zona termoneutral estimada (TNZ) fue 28.1 a al menos 35.0 °C (temperatura experimental superior). Las picas en este estudio mostraron los mismos patrones bimodales de actividad por encima del talud que los reportados en estudios anteriores. La temperatura de las madrigueras en Colorado se correlacionaron con, pero siendo siempre inferiores, la temperatura am - biental actual. La temperatura de las madrigueras en Wyoming mostraron una correlación débil con la temperatura ambiente 20 minutos antes de la temperatura actual de la madriguera. Este estudio es uno de los pocos que presentan datos de las respuestas fisiológicas que las picas podrían tener en las condiciones actuales de calentamiento climático, y el primero en realizar mediciones metabólicas in situ. Nuestros datos respaldan conclusiones de estudios previos, particularmente MacArthur y Wang 1973 y 1974, y Smith 1974, que indican que las picas americanas pueden no tener la capacidad fisiológica para enfrentar las altas temperaturas ambientales y resalta la importancia de las regiones sombreadas bajo las rocas del talud para el comportamiento de termorregulación de las picas

Incorporating Ecohydrologic Variables into Modeling of Patterns of Montane-Mammal Distribution and Abundance

Montane ecosystems have been suggested by both paleontological and contemporary research to often be systems of relatively rapid faunal change, compared to many valley-bottom counterparts. In addition to often (but not always) experiencing greater magnitudes of contemporary change in climatic parameters than species in other ecosystems, mountain-dwelling wildlife must also accommodate often-greater intra-annual swings in temperature and wind speeds, poorly developed soils, and generally harsher conditions. We present new results of ecoregional level analyses of American pikas (Ochotona princeps Richardson) that illustrate how biologically relevant derived hydrological variables can be important to predictors of abundance. We also present new results from the Northern Rocky Mountains that illustrate how behavioral plasticity can, in at least some cases, ‘soften’ the boundaries of species’ bioclimatic niches. Landscape Conservation Cooperatives and Climate Science Centers are newly emerging efforts that may contribute greatly to broad-scale, mechanism-based investigations to inform management and conservation of diverse montane wildlife and the ecosystem components with which they interact. Based on our empirical findings and our review of the literature, we propose tenets that may serves as foundational starting points for our expanding research on montane animals across the Northern Rocky Mountain Region

Understanding Relationships Among Abundance, Extirpation, and Climate at Ecoregional Scales

Recent research on mountain-dwelling species has illustrated changes in species\u27 distributional patterns in response to climate change. Abundance of a species will likely provide an earlier warning indicator of change than will occupancy, yet relationships between abundance and climatic factors have received less attention. We tested whether predictors of counts of American pikas (Ochotona princeps) during surveys from the Great Basin region in 1994-1999 and 2003-2008 differed between the two periods. Additionally, we tested whether various modeled aspects of ecohydrology better predicted relative density than did average annual precipitation, and whether risk of site-wide extirpation predicted subsequent population counts of pikas. We observed several patterns of change in pika abundance at range edges that likely constitute early warnings of distributional shifts. Predictors of pika abundance differed strongly between the survey periods, as did pika extirpation patterns previously reported from this region. Additionally, maximum snowpack and growing-season precipitation resulted in better-supported models than those using average annual precipitation, and constituted two of the top three predictors of pika density in the 2000s surveys (affecting pikas perhaps via vegetation). Unexpectedly, we found that extirpation risk positively predicted subsequent population size. Our results emphasize the need to clarify mechanisms underlying biotic responses to recent climate change at organism-relevant scales, to inform management and conservation strategies for species of concern

Landscape-Scale Conservation And Management Of Montane Wildlife: Contemporary Climate May Be Changing The Rules

Both paleontological and contemporary results have suggested that montane ecosystems to be systems of relatively rapid faunal change compared to many valley-bottom counterparts. In addition to experiencing greater magnitudes of contemporary change in climatic parameters than species in other ecosystems, mountain-dwelling wildlife must also accommodate often greater intra-annual swings in temperature and wind speeds, poorly developed soils, and generally harsher conditions. Research on a mountain-dwelling mammal species across 15 yrs of contemporary data and historical records from 1898-1956 suggest that pace of local extinctions and rate of upslope retraction have been markedly more rapid and governed by markedly different dynamics in the last decade than during the 20th century. This may mean that understanding past dynamics of species losses may not always help predict patterns of future loss. Given the importance of clinal variability and ecotypic variation, phenotypic plasticity, behavioral plasticity, and variation in climatic conditions, for widely-distributed species’ geographic ranges to be determined by different factors in different portions of their range is not uncommon. Consequently, greatest progress in understanding distributionalchange phenomena will occur with coordinated, landscape-scale research and monitoring. Landscape Conservation Cooperatives and Climate Science Centers are newly emerging efforts that may contribute greatly to such broad-scale investigations, e.g., climate-wildlife relationships. Based on our empirical findings and our review of related literature, we propose tenets that may serve as foundational starting points for mechanism-based research at broad scales to inform management and conservation of diverse montane wildlife and the ecosystem components with which they interact

Niche shifts and energetic condition of songbirds in response to phenology of food-resource availability in a high-elevation sagebrush ecosystem

Seasonal fluctuations in food availability can affect diets of consumers, which in turn may influence the physiological state of individuals and shape intra- and inter-specific patterns of resource use. High-elevation ecosystems often exhibit a pronounced seasonal “pulse” in productivity, although few studies document how resource use and energetic condition by avian consumers change in relation to food-resource availability in these ecosystems. We tested the hypothesis that seasonal increases (pulses) in food resources in high-elevation sagebrush ecosystems result in 2 changes after the pulse, relative to the before-pulse period: (1) reduced diet breadth of, and overlap between, 2 sympatric sparrow species; and (2) enhanced energetic condition in both species. We tracked breeding-season diets using stable isotopes and energetic condition using plasma metabolites of Brewer\u27s Sparrows (Spizella breweri), Vesper Sparrows (Pooecetes gramineus), and their food resources during 2011, and of only Brewer\u27s Sparrows and their food resources during 2013. We quantify diet breadth and overlap between both species, along with coincident physiological consequences of temporal changes in resource use. After invertebrate biomass increased following periods of rainfall in 2011, dietary breadth decreased by 35% in Brewer\u27s Sparrows and by 48% in Vesper Sparrows, while dietary overlap decreased by 88%. Energetic condition of both species increased when dietary overlap was lower and diet breadth decreased, after the rapid rise of food-resource availability. However, energetic condition of Brewer\u27s Sparrows remained constant in 2013, a year with low precipitation and lack of a strong pulse in food resources, even though the species\u27 dietary breadth again decreased that year. Our results indicate that diet breadth and overlap in these sparrow species inhabiting sagebrush ecosystems generally varied as predicted in relation to intra- and interannual changes in food resources, and this difference in diet was associated with improved energetic condition of sparrows at least in one year

Effects of Water-Level Management on Nesting Success of Common Loons

Water-level management is widespread and illustrates how contemporary climate can interact directly and indirectly with numerous biological and abiotic factors to influence reproductive success of wildlife species. We studied common loons, an iconic waterbird sensitive to timing and magnitude of waterlevel changes during the breeding season, using a before-after-control-impact design on large lakes in Voyageurs National Park (Minnesota, USA), to assess the effect of anthropogenic changes in hydroregime on their nesting success and productivity. We examined multiple competing a priori hypotheses in an information-theoretic framework, and predicted that magnitude of changes in loon productivity would be greater in the Namakan Reservoir, where water-level management was altered to mimic a more natural hydroregime, than in Rainy Lake, where management remained relatively unchanged. We determined outcomes from 278 nests during 2004–2006 by performing boat-based visits every 3–5 days, and measuring hydrologic, vegetative, and microtopographic covariates. Relative to comparably collected data for 260 total loon pairs during 1983–1986, productivity (chicks hatched/territorial pair) increased 95% in the Namakan Reservoir between the 2 time periods. Nest success declined in both lakes over the 2 study periods but less so in the Namakan Reservoir than in Rainy Lake. Flooding was a primary cause of nest failures (though second nests were less likely to flood). Nest predation appears to have increased considerably between the 2 study periods. Top-ranked models suggested that timing of nest initiation, probability of nest flooding, probability of nest stranding, and probability of nest success were each related to 2–4 factors, including date of initiation, timing of initiation relative to peak water levels, changes in the elevation of the nest edge, maximum waterlevel change between initiation and peak water levels, and maximum water-level change between initiation and nest outcome. The top model for all variables except stranding each garnered \u3e82% of total model weight. Results demonstrate that water-level management can be altered to benefit productivity of common loons. However, nuanced interactions between land-use change, invasive species, human development, recreation, climate change, and recovery of top predators may often complicate both management decisions and interpretation of water-level impacts on wildlife

Ecological Consequences of Anomalies in Atmospheric Moisture and Snowpack

Although increased frequency of extreme‐weather events is one of the most secure predictions associated with contemporary climate change, effects of such events on distribution and abundance of climate‐sensitive species remain poorly understood. Montane ecosystems may be especially sensitive to extreme weather because of complex abiotic and biotic interactions that propagate from climate‐driven reductions in snowpack. Snowpack not only protects subnivean biotas from extreme cold, but also influences forage availability through timing of melt‐off and water availability. We related relative abundances of an alpine mammal, the American pika (Ochotona princeps), to measures of weather and snowpack dynamics over an 8‐yr period that included before and after a year of record‐low snowpack in Washington, USA. We sought to (1) quantify any change in pika abundance associated with the snowpack anomaly and (2) identify aspects of weather and snowpack that influenced abundance of pikas. Pikas showed a 1‐yr lag response to the snowpack anomaly and exhibited marked declines in abundance at elevations below 1,400 m simultaneous with increased abundances at higher elevations. Atmospheric moisture, indexed by vapor pressure deficit (VPD), was especially important, evidenced by strong support for the top‐ranked model that included the interaction of VPD with snowpack duration. Notably, our novel application of VPD from gridded climate data for analyses of animal abundances shows strong potential for improving species distribution models because VPD represents an important aspect of weather that influences the physiology and habitat of biota. Pikas were apparently affected by cold stress without snowpack at mid elevations, whereas changes to forage associated with snowpack and VPD were influential at high and low elevations. Our results reveal context dependency in pika responses to weather and illustrate how snow drought can lead to rapid change in the abundance of subnivean animals

Managing for RADical ecosystem change: applying the Resist-Accept- Direct (RAD) framework

Ecosystem transformation involves the emergence of persistent ecological or social–ecological systems that diverge, dramatically and irreversibly, from prior ecosystem structure and function. Such transformations are occurring at increasing rates across the planet in response to changes in climate, land use, and other factors. Consequently, a dynamic view of ecosystem processes that accommodates rapid, irreversible change will be critical for effectively conserving fish, wildlife, and other natural resources, and maintaining ecosystem services. However, managing ecosystems toward states with novel structure and function is an inherently unpredictable and difficult task. Managers navigating ecosystem transformation can benefit from considering broader objectives, beyond a traditional focus on resisting ecosystem change, by also considering whether accepting inevitable change or directing it along some desirable pathway is more feasible (that is, practical and appropriate) under some circumstances (the RAD framework). By explicitly acknowledging transformation and implementing an iterative RAD approach, natural resource managers can be deliberate and strategic in addressing profound ecosystem change