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74 results for “Pikas”
Pika habitat occupancy survey data for Niwot Ridge and Green Lakes Valley, 2016 - ongoing
Long-term monitoring of habitat occupancy can reveal patterns of habitat use, population dynamics, and factors controlling species distribution. The American pika (Ochotona princeps), a small mammal found in rocky habitats throughout western North America, has been targeted for occupancy studies due to its relatively conspicuous behavior and its unusual adaptations for surviving long, cold winters without hibernation. These adaptations include an unusually high resting metabolic rate and maintenance of body temperatures near the lethal maximum for this species, which would appear to compromise the pika's ability to survive warmer summers. Recent monitoring as well as projections based on future climate scenarios have suggested this species is experiencing a period of range retraction due to warming summers and/or loss of insulating winter snow cover. Niwot Ridge is situated ideally to test competing hypotheses about the trajectory and drivers of pika range shift. The pika is still common throughout the Colorado Rockies, but published models differ markedly regarding projections of the pika’s future distribution in this region. Niwot Ridge has experienced warmer summers as well as shorter periods of insulating snow cover in recent years, and there is evidence that pikas are now less common than they once were in at least one area on the ridge. This study is designed to provide robust data on pika population trends through long-term monitoring of occupancy in a spatially balanced random sample of pika habitat patches centered on Niwot Ridge. Survey plots (n = 72) were selected according to a Generalized Random-Tessellation Stratified (GRTS) algorithm, stratified dichotomously by elevation, average annual snow accumulation (SWE), and probabilities of pika occurrence based on previous data. Each plot extends 12 m in radius from a GRTS point. To ensure that each plot contains at least 10% cover of talus, plot coordinates were adjusted (usually less than 50 m) or replaced
Pika demography data for west knoll and Indian Peaks wilderness, 2008 - ongoing.
Pikas are captured, anesthetized, marked with colored ear-tags, non-lethally sampled, and released at point of capture during June-October. Study sites include a gradient of elevation and slope aspect, allowing a comparative study of pika response to variation in climate and sub-surface microclimate. Daily variation in snow cover and sub-surface temperatures are measured using data loggers placed within the territories of marked pikas. Focal territories are revisited at least once to characterize available vegetation via transect sampling and at least annually to service data loggers and record pika survival. Samples collected for genetic and physiological studies include ectoparasites, blood, saliva, urine, feces and hair as well as records of sex, stage, reproductive status, weight, foot length and body temperature.
Fecal glucocorticoid metabolite levels of American pika (Ochotona princeps) and habitat characteristics of their associated territories found in rock glaciers adjacent to Niwot Ridge and within Rocky Mountain National Park, 2018 - 2019.
To understand whether stress-associated hormones vary with metrics of habitat quality, we measured fecal glucocorticoid metabolite (FGM) levels in the American pika (Ochotona princeps), a small mammal with well-defined habitat (talus), that can vary in quality depending on the presence of rock ice features (RIFs). In 2018, we sampled pika scat from two types of RIFs: “active” rock glaciers thought to harbor subsurface ice recently, and “fossil” rock glaciers considered long devoid of subsurface ice (as classified by Janke 2005, 2007). Specifically, fecal pellets were collected from pika territories located in rock glaciers within eight sites along the Front Range of Colorado: four in Rocky Mountain National Park (2 active, 2 fossil) and four adjacent to Niwot Ridge (2 active, 2 fossil) (pika_fecal_glu_rg.aw.csv). To account for possible seasonal variation in pika FGM, scat samples were collected in the alpine spring and fall. To understand other influences of habitat quality on FGMs, we also measured fine-scale habitat differences between rock glaciers in 2019, including talus depth, clast size, and land cover metrics related to forage (pika_fecal_habitat_rg.aw.csv).
Data from: Phylogenomics of American pika (Ochotona princeps) lineage diversification
<p>Quaternary climate oscillations have profoundly influenced current species distributions. For many montane species, these fluctuations were a prominent driver in species range shifts, often resulting in intraspecific diversification, as has been the case for American pikas (<em>Ochotona princeps</em>). Range shifts and population declines in this thermally-sensitive lagomorph have been linked to historical and contemporary environmental changes across its western North American range, with previous research reconstructing five mitochondrial DNA lineages. Here, we paired genome-wide data (25,244 SNPs) with range-wide sampling to re-examine the number and distribution of intra-specific lineages, and investigate patterns of within- and among-lineage divergence and diversity. Our results provide genomic evidence of <em>O. princeps</em> monophyly, reconstructing six distinct lineages that underwent multiple rounds of divergence (0.809-2.81mya), including a new Central Rocky Mountain lineage. We further found evidence for population differentiation across multiple spatial scales, and reconstructed levels of standing variation comparable to those found in other small mammals. Overall, our findings demonstrate the influence of past glacial cycles on <em>O. princeps</em> lineage diversification, suggest that current subspecific taxonomy may need to be revisited, and provide an important framework for investigations of American pika adaptive potential in the face of anthropogenic climate change.</p>
Fig. 1 in Altitudinal Variation Of Skull Size In Daurian Pika (Ochotona Daurica Pallas, 1868)
Fig. 1. Skull measurements of Daurian pika (Ochotona daurica) vary with altitude, where GLC stands for greatest length of skull, MB for mastoid breadth and NL for nasal length. The entire measurement unit was millimetre (mm) except the skull size, which was centimeter cube (cm3). The results indicate that all of the measurements are negatively correlated with altitude, for skull size: r = –0.420, P <0.001, n = 123; for GLC: r = –0.565, P <0.001, n = 123; for MB: r = –0.191, P = 0.031,
FIGURE 2 in Late Pleistocene and Holocene pikas (Mammalia, Lagomorpha) from Europe and the validity of Ochotona spelaea: New insights based on mtDNA analysis
FIGURE 2. Haplotype network of species of the genus Ochotona based on the analysis of cytochrome b mtDNA sequences.
FIGURE 1 in Late Pleistocene and Holocene pikas (Mammalia, Lagomorpha) from Europe and the validity of Ochotona spelaea: New insights based on mtDNA analysis
FIGURE 1. Phylogenetic tree of the genus Ochotona based on the analysis of cytochrome b mtDNA sequences.
Рис. 2. НижнечеΛюстные кости из шурфа Ш-1, кв. Б-3: А — собоΛь (Martes zibellina); Б — заяц-беΛяк (Lepus timidus); В — пищухи (Ochotona sp.) Fig. 2. Mandibular bones from D-1, sq. B-3: A — sable (Martes zibellina); Б — white hare (Lepus timidus); В — pikas (Ochotona sp.) in New data on the Holocene vertebrate fauna of the Middle Lena and Aldan Rivers basins (Yakutia) based on the materials from archaeological sites Jampa, Kuznets I, II Daban-Yuryakh, and Buor-Khaya I, II, III
Рис. 2. НижнечеΛюстные кости из шурфа Ш-1, кв. Б-3: А — собоΛь (Martes zibellina); Б — заяц-беΛяк (Lepus timidus); В — пищухи (Ochotona sp.) Fig. 2. Mandibular bones from D-1, sq. B-3: A — sable (Martes zibellina); Б — white hare (Lepus timidus); В — pikas (Ochotona sp.)
Data from: Phylogenomics of American pika (Ochotona princeps) lineage diversification
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Sampling a pika’s pantry: Temporal shifts in nutritional quality & over-winter preservation of American pika food caches
Climate change is increasing temperature, decreasing precipitation, and increasing atmospheric CO2 concentrations in many ecosystems. As atmospheric carbon rises, plants may increase carbon-based defenses such as phenolics, thereby potentially affecting food quality, foraging habits, and habitat suitability for mammalian herbivores. In alpine habitats, the American pika (Ochotona princeps) is a model species for studying effects of changing plant chemistry on mammals. To survive between growing seasons, pikas cache “haypiles” of plants rich in phenolics. Although they are acutely toxic to pikas, phenolic compounds help plants retain biomass and nutrition during storage, and they break down over time. Alpine avens (Geum rossii, Rosales: Rosaceae) is a high-phenolic plant species that comprises up to 75% of pika winter diet in Colorado. Here, we tested the hypothesis that contemporary climate change has affected the nutritional value of Alpine avens to pikas in the last 30 years. Specifically, we compared phenolic activity, nutritional quality, and overwinter preservation of plants collected at Niwot Ridge, Colorado (USA) in 1992 to those collected between 2010 – 2018, spanning nearly three decades of climate change. Phenolic activity increased in alpine avens since 1992, while fiber and nitrogen content decreased. Importantly, overwinter preservation of plant biomass also increased, particularly on windblown slopes without long-lasting snow cover. Previous studies indicate that pikas at this site still depend on alpine avens in their winter food caches. Increasing phenolic content in alpine avens could therefore enhance the preservation of haypiles over winter; however, if pikas must further delay consuming these plants to avoid acute toxicity, then he nutritional gains from enhanced preservation may not be beneficial. This study provides important insights into how changing plant chemistry will affect mammalian herbivores in the future.
Physiological stress of American pika (Ochotona princeps) and associated habitat characteristics for Niwot Ridge, 2018 - 2019
Temporal variation in a metric of stress might signify changes in an organism’s internal or external environment, but spatial variation in stress response could also signify spatial variation in habitat quality. Any stress response to habitat quality can be complicated or modulated, however, by strategies like escape in space (e.g., animal movements) or time (e.g., seed banks) that allow access to different conditions. Spatial and temporal variation in response to potential stressors has received little study in wild animals, especially at scales appropriate for relating stress to specific habitat characteristics. Here, we use the American pika (Ochotona princeps), a highly territorial small mammal, to investigate stress response within and among territories. For individually territorial animals such as pika, differences in habitat quality should lead to differences in the levels of stress exhibited by territory owners. In this study, we indexed stress by measuring stress hormone metabolites in feces collected non-invasively from pika territories. Feces were collected from 20 territories every two weeks from June to September of 2018 (pika_fecal_glut.aw.data.csv). In 2019, habitat metrics were recorded at each territory (pika_fecal_glut_habitat.aw.data.csv).
Divergent adaptations in resource-use traits explain how pikas thrive on the roof of the world
Life in extreme environments is possible through multilevel adaptations to physical and biotic stresses. At high elevations, species face numerous challenges, besides low oxygen levels, but previous studies have focused on genetic and physiological adaptations to chronic hypoxia while overlooking other key strategies for thriving in alpine landscapes. Here, we investigate resource-use trait adaptations to extreme elevations using pikas as a model, lagomorphs distributed up to 6200 metres and reaching maximum diversity on the Qinghai-Tibet plateau, the highest plateau on Earth. Specifically, we assess cranial evolution in pikas using geometric morphometric and phylogenetic comparative techniques to determine whether adaptations among high-elevation biota shown at the molecular and physiological levels also occur in resource-use traits. We further explore the roles of two contrasting lifestyles (burrowing and rocky-dwelling) in cranial evolution. We found that alpine species exhibit striking phenotypic specialization to distinct microhabitats. Contrary to physiological and genetic adaptive convergence, we show that the cranium has undergone adaptive divergence likely reflecting past resource competition in highlands and long-term association with alpine landscapes. Our analyses also reveal that the evolution of burrowing lifestyle allows high-elevation pikas to explore novel niches and boosts their phenotypic diversification. In addition to cold and hypoxia tolerance, high cranial specialization, the appearance of burrowing habits, and strong niche separation explain how pikas overcome alpine stresses and flourish on the highest plateau on Earth. By contrast, when moving to spatially complex and heterogeneous vegetation zonation, pikas exhibit generalist skull forms able to exploit diverse habitats. These findings mirror previously reported intraspecific patterns in mammals, suggesting a general morphological response in resource-exploiting traits to cope with distinct selection pressures across elevation zones. Phenotypic diversity is further constrained by rocky habitats, resulting in convergent skulls. Our study highlights that adaptations to extreme environments occur at multiple levels of organization, but can lead to distinct evolutionary paths depending on which selective forces they respond to. The evolution of burrowing behaviour represents a landmark in the evolutionary history of pikas. We further show that rocky habitats impose strong ecological pressures, leading to convergent responses in resource-use traits, which is rarely documented in mammals.
Data from: Northern pikas experience reduced occupancy due to surrounding human land use despite the occurrence of suitable microclimates
<p>Aim: Despite warming temperatures, some species are found persisting at the trailing edge of their distribution. Microclimates provided by complex topography are considered a key factor in these cases of range stationarity, buffering stress from exposure to warming and enabling persistence. However, for species with trailing-edges located in human-modified landscapes, refugial conditions provided by microclimates could be disrupted by human activities. Here, we aimed to understand the determinants of trailing-edge occupancy for a small lagomorph found in rocky patches harboring cool microclimates.</p> <p>Location: Hokkaido Island, Japan</p> <p>Taxon: Northern pika (<em>Ochotona hyperborea</em>)</p> <p>Methods: We surveyed the occupancy of northern pikas across a wide elevational gradient (350–2200 m) for two consecutive summers. Ambient air and microhabitat (i.e., rock interstices) thermal conditions were measured to assess their relationship. We then analyzed their effects on occupancy at two nested spatial scales: (1) whole-distribution, and (2) at identified trailing-edge sites where we explored the effects of microclimates and surrounding human activities (i,e., distance to nearest road and area of human land use such as plantation forests or agricultural fields).</p> <p>Results: Overall, rock interstices exhibited cooler conditions than ambient air with temperature differences of 1–2 ºC. The overall distribution of northern pikas was affected by both mean ambient temperature and microhabitat availability, with warmer (lower elevation) sites with less microhabitats corresponding to the trailing edge of its distribution. Interestingly, trailing edge occupancy patterns were best explained by the negative effect of surrounding human land despite the existence of suitable microclimates in the rocky patches.</p> <p>Main conclusions: Our findings suggest that the local refugial conditions supported by cool microclimates are likely to be disrupted by the effects of human land at the larger landscape scale. This result highlights the importance of considering the effects of human activities and landscape alteration for effective microrefugia conservation. --</p>
Data from: Putative climate adaptation in American pikas (Ochotona princeps) is associated with copy number variation across environmental gradients
<p>Improved understanding of the genetic basis of adaptation to climate change is necessary for maintaining global biodiversity moving forward. Studies to date have largely focused on sequence variation, yet there is growing evidence that suggests that changes in genome structure may be an even more significant source of adaptive potential. The American pika (<em>Ochotona princeps</em>) is an alpine specialist that shows some evidence of adaptation to climate along elevational gradients, but previous work has been limited to single nucleotide polymorphism (SNP)-based analyses within a fraction of the species range. Here, we investigated the role of copy number variation underlying patterns of local adaptation in the American pika using genome-wide data previously collected across the entire species range. We identified 37-193 putative copy number variants (CNVs) associated with environmental variation (temperature, precipitation, solar radiation) within each of the six major American pika lineages, with patterns of divergence largely following elevational and latitudinal gradients. Genes associated (<em>n</em>=158) with independent annotations across lineages, variables, and/or CNVs had functions related to mitochondrial structure/function, immune response, hypoxia, olfaction, and DNA repair, some of which have been previously linked to putative high elevation and/or climate adaptation that may serve as important targets in future studies.</p>
Supplementary materials: Return of the pika: American pikas re-occupy long-extirpated, warm locations
<p>To accompany: Return of the pika: American pikas re-occupy long-extirpated, warm locations by Constance I. Millar and Andrew T. Smith, Nature Notes.</p> <p>American pika re-colonization sites identified in this study </p> <p>Bodie State Historic Park – Noonday Mine 38.004 N; -119.1005 W; 2,615 m Site also clearly identified in maps in Smith (1974a), Smith & Gilpin (1997), Smith & Nagy (2015).</p> <p>North Mono Craters Site 37.9116 N; -118.9985 W; 2,145-2,250 m</p>
Data from: Predicting range shifts of pikas (Mammalia, Ochotonidae) in China under scenarios incorporating land-use change, climate change, and dispersal limitations
<p><span>Two of the most important forces affecting biodiversity are land-use change (LUC) and global climate change (GCC). Previous studies have modeled their impacts on species separately and together, but few have done so for multiple species with dispersal limitations incorporated into the models.</span></p> <p><span>We integrate species distribution models plus a dispersal model to predict LUC and GCC impacts on the ranges of five species of pikas in the Qinghai-Tibet Plateau region of China. Pikas are sensitive to land-use and climate change, and have limited dispersal abilities.</span></p> <p><span>The predicted impacts of LUC and GCC on pikas vary between species as well as between LUC and GCC projections. Incorporation of dispersal limitations appreciably restricts the amount of colonized habitat. For all five species, the amount of habitat abandoned or colonized when LUC and GCC are modeled together is less than the sum of LUC and GCC modeled separately. Three of the five species experience a net increase in occupied habitat by 2080 relative to their current ranges under all modeled projections. However, relative to a "Dispersal Only" baseline scenario that assumes no environmental change but continued range expansion into suitable, unoccupied habitat, all five species suffer a net loss of occupied habitat by 2080 under some or all projections.</span></p> <p><span>Predictions of future distributions of species based solely on LUC or GCC, as well as predictions assuming additive impacts, can be misleading. Inclusion of dispersal limitations in models markedly alters predicted future distributions of species. The use of a "Dispersal Only" scenario provides a different and perhaps more accurate way to gauge net impacts to species. Future work should consider incorporating all these parameters to better predict the impacts of LUC and GCC on biodiversity.</span></p>
Data from: Genome-wide analysis reveals associations between climate and regional patterns of adaptive divergence and dispersal in American pikas
<p>Understanding the role of adaptation in species responses to climate change is important for evaluating the evolutionary potential of populations and informing conservation efforts. Population genomics provides a useful approach for identifying putative signatures of selection and the underlying environmental factors or biological processes that may be involved. Here, we employed a population genomic approach within a space-for-time study design to investigate the genetic basis of local adaptation and reconstruct patterns of movement across rapidly changing environments in a thermally-sensitive mammal, the American pika (<i>Ochotona princeps</i>). Using genotypic data at 49,074 single nucleotide polymorphisms (SNPs), we analyzed patterns of genome-wide diversity, structure, and migration along three independent elevational transects located at the northern extent (Tweedsmuir South Provincial Park, British Columbia, Canada) and core (North Cascades National Park, Washington, USA) of the Cascades lineage. We identified 899 robust outlier SNPs within- and among-transects. Of those annotated to genes with known function, many were linked with cellular processes related to climate stress including ATP-binding, ATP citrate synthase activity, ATPase activity, hormone activity, metal ion-binding, and protein-binding. Moreover, we detected evidence for contrasting patterns of directional migration along transects across geographic regions that suggest an increased propensity for American pikas to disperse among lower elevation populations at higher latitudes where environments are generally cooler. Ultimately, our data indicate that fine-scale demographic patterns and adaptive processes may vary among populations of American pikas, providing an important context for evaluating biotic responses to climate change in this species and other alpine-adapted mammals.</p>
Life on the edge: a changing genetic landscape within an iconic American pika metapopulation over the last half century
<p>Declines and extirpations of American pika (<em>Ochotona princeps</em>) populations at historically occupied sites started being documented in the literature during the early 2000s. Commensurate with global climate change, many of these losses at peripheral and lower elevation sites have been associated with changes in ambient air temperature and precipitation regimes. Here, we report on a decline in available genetic resources for an iconic American pika metapopulation, located at the southwestern edge of the species distribution in the Bodie Hills of eastern California, USA. Composed of a highly fragmented habitat created by hard rock mining, the ore dumps at this site were likely colonized by pikas at the end of the 19th century from nearby natural talus outcrops. Genetic data extracted from both contemporary samples and archived natural history collections allowed us to track population and patch-level genetic diversity for Bodie pikas across three distinct sampling points during the last half-century (1948, 1988-1991, 2013-2015). In addition to declines in within-population allelic diversity and expected heterozygosity, we observed an increase in population structure and a reduction in effective population size from more extensive sampling of extant patches during 1988-1991 and 2013-2015, respectively. Furthermore, census records from the last 50 years as well as archived museum samples collected in 1947 from a nearby pika population in the Wassuk range (NV, USA) provide further support for the increasing isolation and genetic coalescence occurring in this region. This study highlights the importance of museum samples and long-term monitoring in contextualizing our understanding of population viability.</p>
Data from: Predicting range shifts of pikas (Mammalia, Ochotonidae) in China under scenarios incorporating land-use change, climate change, and dispersal limitations
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Data from: Putative climate adaptation in American pikas (Ochotona princeps) is associated with copy number variation across environmental gradients
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