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In this paper, we examine in a holistic manner how entrepreneurs' beliefs in climate change combine with psychological attributes and firm contextual conditions to produce high levels of personal resilience. To do so, we draw from complexity theory and employ a configurational approach with fuzzy set qualitative comparative analysis (fsQCA) using survey data from153 small business owners from Aberdeenshire, Scotland and Wyoming, USA, two regions where the local economies have traditionally been reliant on the fossil fuel industry. The analysis indicates that high entrepreneurial resilience arises from four unique configurations that capture the complex interactions of entrepreneurs' beliefs about climate change with their psychological attributes of self-efficacy, optimism, and locus of control, along with the size and profitability of their firms. Analyzing patterns across the configurations reveals that efficacy-driven, optimistic internals (EOIs) develop high resilience through psychological synergy. Entrepreneurs who are climate conscious optimistic internals (CCOIs), climate conscious efficacy-driven internals (CCEIs) and climate conscious efficacy-driven optimists (CCEOs) use a mechanism of climate conscious empowerment shifting to achieve high levels of resilience. Demonstrating how beliefs about climate change complement other psychological attributes that impact entrepreneurs' abilities to deal with adverse situations has important implications for entrepreneurship research and economic development policy. [ABSTRACT FROM AUTHOR]

In this paper, we explore and integrate different currencies that may underlie large-game hunting to guide a trans-Holocene analysis of variation in artiodactyl utilization using massive archaeofaunal data-sets from predominantly open-air sites from the Bonneville and Wyoming basins. The available empirical data continue to suggest that artiodactyls yield consistently higher return rates than lagomorphs allowing us to leverage predictions from both the prey choice and energetic risk-gain models that the relative importance of artiodactyl hunting should scale closely with climate-based change in their abundance on the landscape. We document with modeled climate data that seasonal variables correlated with the relative frequency of artiodactyl hunting, but that summer temperature had a significant overriding effect in both regions. Controlling for the negative relationship between summer temperature and artiodactyl abundances, we then document enhanced artiodactyl hunting in general and bison more specifically during the Fremont period that is consistent with a costly signaling hypothesis and the unique socio-ecological conditions of this context. Thus, climatic variation and its influence on artiodactyl abundances drives the overall trajectory of Holocene large game hunting variation but measurable and more subtle influences of costly signaling are also detected. [ABSTRACT FROM AUTHOR]

The impact of climate change on water resources is a major issue for regions in the world. Climate parameters such as temperature and precipitation are expected to change in the future and could significantly impact available water resources. This paper assesses long-term water availability over the North Platte River watershed, Wyoming, by utilizing the variable infiltration capacity (VIC) hydrologic model and developing streamflow projections under anthropogenic climate change conditions. Uncertainties in the scenarios of climate change and global climate models are assessed by utilizing ensemble multiple models and multiple scenarios from the World Climate Research Programme's database. The simulated streamflows are compared using an intermodel interscenario approach. Based on streamflow projections, there is a possibility of increased annual streamflow for this region through 2100, with maximum streamflow during 2085-2090. The simulated annual streamflows for future periods vary from −20 to 62% with respect to the baseline period (1971-2000). In the simulations, the wet months are getting wetter, whereas the summer months are found to be growing drier. The streamflow projections and the range of streamflow can be utilized by decision makers in future water supply and demand management study. [ABSTRACT FROM AUTHOR]

A broad range of participatory methods can be employed to understand the vulnerability of social-ecological systems threatened by various drivers of change including climate change and land-use change. Understanding this vulnerability is critical for managing natural resources, particularly water resources that flow across jurisdictional boundaries, and support conflicting uses. This paper demonstrates Q-methodology, a promising participatory method infrequently applied in the vulnerability context, with a case study investigation of the vulnerability of stakeholders reliant on water-based ecosystem services derived from the Shoshone National Forest in Wyoming, USA. The approach identified four distinct viewpoints regarding vulnerability, including an environmental perspective, agricultural perspective, Native American perspective, and recreation perspective. The distinct viewpoints highlighted disparate levels of importance related to 34 water benefits, such as commercial irrigation, oil and natural gas extraction, river-based fishing, and cultural and spiritual use. A diverse range of drivers of change threatening important water benefits were also identified, including pollution, too much management intervention, and development of recreation opportunities. The potential benefits of Q-methodology for vulnerability assessment include a rank-ordering exercise that elicits preferences for tradeoffs, and statistical derivation of a small number of perspectives about the topic. [ABSTRACT FROM AUTHOR]

The reproductive ecology of rare plants is seldom studied, yet the persistence of plant populations depends on successful mutualisms with pollinators. As atmospheric temperatures rise, phenology of plants and pollinators may become mismatched. We investigated the reproduction of Trifolium barnebyi (Barneby's clover), a mat‐forming perennial endemic to central Wyoming, USA, that grows in the crevices of sandstone bedrock. Our objectives were to evaluate a method for monitoring changes in cover as well as assess the pollination and seed‐set of T. barnebyi. We established five monitoring transects using a divided frame to estimate percent cover. We conducted seed‐set experiments at three locations to measure self‐pollination and the degree to which pollinating insects limited seed production. We used vane traps and bee bowls to capture pollinators, and examined pollen carried on bees. Percent cover along transects declined over the four year period and was associated with spring precipitation. Trifolium barnebyi did not self‐pollinate and relied on pollinators to produce seeds. The number and mass of viable seeds per flower, and the number of bees captured increased as the season progressed, indicating that more and larger seeds were made when more pollinators were present. Blooming of T. barnebyi ranged between April and June, depending on the microhabitat the plant lived in, and we observed much higher seed production in later‐blooming plants. Pollen from T. barnebyi was primarily carried by Andrena bees, although we found smaller amounts of pollen on seven other bee genera. A mismatch in timing between blooming and pollinating insect emergence could limit seed production in T. barnebyi if plants bloom earlier over time and bee emergence does not follow the same phenology. Rare plants can be pollinated by rare pollinators showing that conserving these pollinators is crucial for rare plants and early blooming species may be higher at risk. [ABSTRACT FROM AUTHOR]

Sagebrush (Artemisia spp.) ecosystems provide critical habitat for the Greater sage‐grouse (Centrocercus urophasianus), a species of conservation concern. Thus, future loss of sagebrush habitat because of land use change and global climate change is of concern. Here, we use a dynamic additive spatiotemporal model to estimate the effects of climate on sagebrush cover dynamics at 32 sage‐grouse management (core) areas in Wyoming. We use the fitted models to quantify the sensitivity of each management area to precipitation and temperature, and to make probabilistic projections of sagebrush cover from present to 2100 under three climate change scenarios. Global circulation models predict an increase in temperature and no change in precipitation for Wyoming. Sensitivity to climate varied among management areas, but the most common response (70% of management areas) was a positive effect of temperature on sagebrush performance. The combination of positive sensitivity to temperature and the predicted increase in temperature under all climate change scenarios resulted in projections of increased sagebrush cover for most management areas. We characterized management areas as "optimal" or "suboptimal" based on the percentage of grid cells in each management area with sagebrush cover exceeding a nesting habitat target value. Only 18% of management areas are projected to switch from being currently optimal to suboptimal in the future. Thirty‐five percent of management areas are projected to switch from being suboptimal to optimal. The most common outcome (47%) was for currently suboptimal management areas to remain suboptimal, even though average cover tended to increase in those areas. The direct effects of climate change appear to favor sagebrush performance in the future for most sage‐grouse core areas in Wyoming. Our approach is broadly applicable to quantitative climate change assessments where remotely sensed estimates of habitat‐defining vegetation are available. [ABSTRACT FROM AUTHOR]

The earth's mountains continue to lose water. Glaciers are melting and mountain snow/rain balance tilts increasingly liquescent. Water is running off sooner—sometimes overfilling reservoirs, causing flooding, and setting the stage for late-season shortages. One adaptive strategy is to recover and enhance water-storage capacities of headwater riparian systems. Grazing, a common use of headwater lands, affects both soils and vegetation. To better understand how grazing might affect water storage and other ecosystem services of high elevation riparian wetlands, we measured soil-profile temperatures, soil organic matter (SOM), and phytomass at six sites in the upper Sweetwater River sub-basin of Wyoming, USA, where fence lines allowed us to contrast grazing management. We found grazed wetlands consistently had warmer soils than fenced wetlands. We found added evidence that SOM is important in both soil temperature control and water-storage potential of wetlands. We review evidence that warmer soil temperatures and drying cause loss of SOM with the implied concomitant C losses through erosion and emissions. We recommend land managers of temperate-climate headwater systems consider the need to end growing seasons with full stands of riparian vegetation to reduce soil warming and to build organic matter—particularly on lands where municipalities and other downstream water users are seeking long-term increases in water yields and less flooding. [ABSTRACT FROM AUTHOR]

Increased wildfire activity and climate change have intensified disturbance regimes globally and have raised concern among scientists and land managers about the resilience of disturbed landscapes. Here we test the effects of climate, topographic variation and pre‐fire stand structure on regeneration in lodgepole pine (Pinus contorta var. latifolia) forests following high‐severity fire over the past seven decades.We surveyed lodgepole pine regeneration 8–67 years after eight high‐severity fires in western Colorado and southern Wyoming. We used dendroecological methods and machine learning to (a) identify temporal trends in post‐fire regeneration and (b) examine influences of climate on post‐fire regeneration, with focus on post‐fire establishment, initial post‐fire density and radial growth.All burned sites reached a median stocking density of ≥150 seedlings/ ha, but there was a large range of spatial heterogeneity, with regeneration being absent or scarce in many plots, implying a trend of increasing patchiness with likely cascading effects on subsequent patterns and processes. Our analysis indicated that (a) post‐fire regeneration is influenced by pre‐fire stand structure (stand age and density), elevation and post‐fire minimum temperature; (b) pre‐fire densities of >14,000 stems/ha promoted successful stocking (≥150 seedlings/ha) and reduced lag between the disturbance and initial regeneration; and (c) minimum post‐fire temperatures >−1.6°C reduced lag of initial regeneration and promoted initial radial growth.Synthesis. Our study demonstrates that lodgepole pine in high‐elevation forests are regenerating following fires under recent climatic trends, but that regeneration is affected by post‐fire climatic conditions. Importantly, forest patchiness may be increasing in a way that affects future ecological dynamics and may compromise the resilience of these systems. [ABSTRACT FROM AUTHOR]

Despite two decades of research into the earliest Eocene fossils of the Rocky Mountain interior of North America, almost nothing is known of the squamates (lizards and snakes) from this time, nor of the response of this component of the terrestrial biota to climate change near the Paleocene/Eocene boundary. The present study addresses this lacuna. Sixteen squamate species are described in the earliest Eocene (Wa0) Castle Gardens local fauna of the lower-most Willwood Formation of the Bighorn Basin, Wyoming. These include: two new iguanids, a species similar to Geiseltaliellus on the stem of Corytophaninae (basilisks and relatives) and a polychrotine (anoles and relatives); new stem representatives of the xantusiid (night lizard) clades Lepidophyma and Xantusia; a 'higher' amphisbaenian (worm lizard) of indeterminate affinities; six anguids, including a new species on the stem of Anniella (California legless lizards), a ?stem diploglossine (galliwasps), a ?stem gerrhonotine (alligator lizards) and a new glyptosaurinemorphologically intermediate between 'melanosaurins' and Glyptosaurini; a new anguimorph of undetermined affinities; and two species compared to the varanid (monitor lizard) taxon Saniwa. At least seven species at Castle Gardens were recent immigrants. The nearest relatives of one of these is obscure, but the other six (three iguanids, stem Lepidophyma, stem Anniella, ?stem Diploglossinae) have living relatives exclusively or almost exclusively confined to warm and frost-free (megathermal) parts of theNewWorld.Amonglizards,dispersal coincident with climaticwarming near the Paleocene/Eocene boundary was predominantly intracontinental. It is argued that when habitat tracking occurs and phylogenetic niche conservatism obtains, species within a clade could migrate in broad concert in response to climate change. Mid-latitude fossil groups may have contributed directly to the modern tropical biota, making palaeontological data of direct relevance to evaluating historical influences on modern biodiversity patterns. [ABSTRACT FROM AUTHOR]

Microsyopidae is a family of plesiadapiforms known from over 1500 stratigraphically controlled specimens from the southern Bighorn Basin of Wyoming spanning the first three million years of the early Eocene. The early Eocene is characterized by rapid fluctuations in climate during the period represented by this collection of microsyopids, making this an ideal sample to examine how climate may have influenced early stem primate biology, particularly diet. An evolving lineage of microsyopids is known from before, during, and after Biohorizon A, a faunal turnover event associated with a period of localized cooling. Dental topographic analysis (DTA) metrics quantify functional aspects of molars including curvature, complexity and relief, and covary with diet in extant taxa. Here, we use DTA to examine microsyopid dietary change over time, particularly in association with this cooling event. Our results suggest that microsyopids had molars that are functionally like extant insectivorous/omnivorous euarchontans. The earliest occurring species, Arctodontomyswilsoni, is characterized by molars that became more like modern insectivores over time. During Biohorizon A, A. wilsoni is replaced by A. nuptus, which has molars that are more like those of extant omnivores with a mixed diet including fruit. After Biohorizon A, A. nuptus appears more insectivorous, as is the later occurring Microsyopsangustidens, which evolves from A. nuptus. Overall, we provide potential evidence for a causal scenario in which local climate change coincided with a dietary transition among microsyopids. Our results have implications for understanding how diet was a prime mover for the evolution of Primates. [ABSTRACT FROM AUTHOR]

Terrestrial ecosystems in North America changed substantially during the Neogene. Previous authors have documented changes in plants and mammals but squamates have received comparatively little attention. Several Miocene lizard fossils were described previously from the Split Rock Formation (Wyoming), which was deposited just before or during the mid-Miocene Climatic Optimum (c. 18–14 Ma). I re-evaluate the identifications of some of the previously published fossil lizards from the Split Rock Formation and describe several new fossil lizards. I focus on the iguanians and revise the biogeographical and temporal context for the evolution of several clades. I establish a minimum age for crown Phrynosomatidae and describe the oldest known occurrence of Crotaphytidae. The fossils provide evidence of a relatively modern lizard fauna in central North America by ∼17.5 Ma and support a substantial turnover from the Eocene to the middle Miocene. I also describe a new taxon, Caeruleodentatus lovei, with a distinctive dentary morphology. The revised iguanian lizard fauna is more diverse than previously described. I discuss difficulties and considerations with using apomorphies to identify fossils, biogeographical biases that affect fossil identifications, and the previous and future use of fossils from the Split Rock Formation in divergence time analyses. I recommend that comparative samples used for identifying fossils should not be intentionally limited by biogeography or stratigraphy, and underscore the importance of topology selection when constructing an apomorphy-based diagnosis. While apomorphy-based diagnoses may decrease taxonomic resolution of fossil identifications, they do not necessarily decrease our capacity to interpret the phylogenetic, biogeographical or ecological significance of fossils. [ABSTRACT FROM AUTHOR]

Alluvial fans occur in all climatic and tectonic environments. However, most descriptions of fan features and sediments have focused on arid and semiarid regions. This paper describes the sediments and soil ages on 63 alluvial fans in a subhumid climate (mean annual precipitation of 45–52 cm). SSURGO soil data were merged with geologic and topographic data in the ArcMap© GIS platform to develop a series of maps showing variations across fan surfaces in sediment textures and surface stability ages. Particle size data (percent cobble and percent total gravel) from the upper 150 cm of sediments cluster into six textural groups that are aligned along a trend of decreasing gravel percentage (decreasing stream capacity) and decreasing cobble percentage (decreasing stream competency). The groups of higher cobble and gravel percentages extend from fan apex to toe in both the shallow (<50 cm depth) and deeper (>100 cm depth) layers with groups of lower cobble and gravel percentage occurring along fan margins in the shallow (<50 cm depth) layer. The thickness of B and Bt horizons from representative soil profiles were used to calculate proportional soil ages based on 10Be residence times in loessial Bt horizons and correlation of gravelly fan soils to similar gravelly soils on nearby Pinedale outwash. This approach identified six stability episodes since the end of the Bull Lake beginning at ~100 ka, ~38 ka, ~27 ka, ~16 ka, ~10 ka, and <2 ka. The proportional soil ages correlate closely with fan chronologies constrained by TL and OSL ages in nearby areas. Soil ages and sediment textural groups differed between fan populations along the mountain front with active faulting and those along the stable mountain front. Fan stability surfaces older than 16 ka are preserved only at fault termini. Holocene faulting resulted in fans with (1) coarser sediments, (2) younger sediments, (3) progressive onlap of younger sediments, (4) the absence of relic fan surfaces, landslides and colluvium at the mountain front, and (5) the onlap of alluvial fans onto the floodplain of the axial stream. Sediment pulses related to individual fault events could not be definitively identified because of concurrent climatic changes. The study demonstrates that both climatic and tectonic conditions influence sediment textures and fan surfaces ages. • Sediments cluster into six groups reflecting progressive changes in stream power • The same high capacity/high competency textural groups dominate all fan sediments • Six fan-surface stability episodes since Bull Lake (100, 38, 27, 16, 10, and < 2 ka) • Relict fans >38 ka only occur at fault termini; elsewhere fan surfaces are <16 ka • Identified fan-stability episodes are regional and correspond to climate changes [ABSTRACT FROM AUTHOR]

Species' distributions are often discontinuous near the edge of the range where the environment may be more variable than the core of the range. Range discontinuity can reduce or cut off gene flow to small peripheral populations and lead to genetic drift and subsequent loss of genetic diversity. The southern extent of the Great Gray Owl (Strix nebulosa) range in North America is discontinuous, unlike their northern core range across the boreal forests. We sampled owls from five different locations on the periphery of the range across the western US (Wyoming, Idaho, California, northern Oregon, and southern Oregon) to investigate genetic population structure and genetic diversity. Using a reduced-representation genomic sequencing approach to genotype 123 individuals at 4817 single nucleotide polymorphic loci, we identified four genetically differentiated populations: California, southern Oregon, northern Oregon, and Wyoming and Idaho grouped together as a single Rocky Mountain population. The four genetically differentiated populations of Great Gray Owls identified in this study display high differentiation and low genetic variation, which is suggestive of long-term isolation and lack of connectivity, potentially caused by range discontinuity. The populations that lack habitat connectivity to the rest of the breeding range (i.e. those in California and Oregon) had lower genetic diversity than the Rocky Mountain population that is connected to the core of the range. These factors and other risks (such as disease and human-caused mortality) heighten susceptibility of these range-edge populations to future habitat and climate changes, genetic diversity erosion, and potential extinction vortex. For these reasons, protecting and monitoring this species on the southern edge of their range is vital. [ABSTRACT FROM AUTHOR]

To increase resource gain, many herbivores pace their migration with the flush of nutritious plant green‐up that progresses across the landscape (termed "green‐wave surfing"). Despite concerns about the effects of climate change on migratory species and the critical role of plant phenology in mediating the ability of ungulates to surf, little is known about how drought shapes the green wave and influences the foraging benefits of migration. With a 19 year dataset on drought and plant phenology across 99 unique migratory routes of mule deer (Odocoileus hemionus) in western Wyoming, United States, we show that drought shortened the duration of spring green‐up by approximately twofold (2.5 weeks) and resulted in less sequential green‐up along migratory routes. We investigated the possibility that some routes were buffered from the effects of drought (i.e., routes that maintained long green‐up duration irrespective of drought intensity). We found no evidence of drought‐buffered routes. Instead, routes with the longest green‐up in non‐drought years also were the most affected by drought. Despite phenological changes along the migratory route, mule deer closely followed drought‐altered green waves during migration. Migrating deer did not experience a trophic mismatch with the green wave during drought. Instead, the shorter window of green‐up caused by drought reduced the opportunity to accumulate forage resources during rapid spring migrations. Our work highlights the synchronization of phenological events as an important mechanism by which climate change can negatively affect migratory species by reducing the temporal availability of key food resources. For migratory herbivores, climate change poses a new and growing threat by altering resource phenology and diminishing the foraging benefit of migration. [ABSTRACT FROM AUTHOR]

1. Semi‐arid rangeland productivity is limited by precipitation, and yet droughts are projected to increase in frequency and duration with unknown impacts on insect populations. As some katydids prolong diapause and remain in an egg bank as a blastoderm for multiple growing seasons, is it possible that drought could prolong diapause and promote outbreaks by synchronising embryonic development and hatching of Mormon crickets, Anabrus simplex, after moisture is restored? 2. In this study, a high‐elevation Wyoming population (WY) was compared with a mid‐elevation Idaho (ID) and a low‐elevation Oregon population (OR). It was predicted that eggs from the drier ID and OR habitats would be more tolerant of desiccation. Developmental state and water loss of eggs were measured after drought treatments, and when moisture was restored. 3. The two drier treatments had significantly more WY eggs prolonging diapause until after drought ended compared with the two wetter treatments. Whether WY eggs developed in the second or subsequent warm periods was independent of drought treatments. Significantly fewer OR embryos developed in the driest treatment compared with the others, whereas almost all ID eggs developed irrespective of the drought treatment. 4. In conclusion, Mormon crickets can delay embryonic development to improve drought tolerance. Although drought did not synchronise development and hatching, diapause plasticity allowed insects to cope and await more favourable conditions. 5. Unexpectedly, eggs from WY (the highest, wettest site) were more tolerant, because postponing development resulted in less water loss than in developed embryos. OR egg loss was also reduced by prolonging diapause, relative to ID, which developed in even the driest conditions. [ABSTRACT FROM AUTHOR]

In subalpine forests of the western United States that historically experienced infrequent, high‐severity fire, whether fire management can shape 21st‐century fire regimes and forest dynamics to meet natural resource objectives is not known. Managed wildfire use (i.e., allowing lightning‐ignited fires to burn when risk is low instead of suppressing them) is one approach for maintaining natural fire regimes and fostering mosaics of forest structure, stand age, and tree‐species composition, while protecting people and property. However, little guidance exists for where and when this strategy may be effective with climate change. We simulated most of the contiguous forest in Grand Teton National Park, Wyoming, USA to ask: (1) how would subalpine fires and forest structure be different if fires had not been suppressed during the last three decades? And (2) what is the relative influence of climate change vs. fire management strategy on future fire and forests? We contrasted fire and forests from 1989 to 2098 under two fire management scenarios (managed wildfire use and fire suppression), two general circulation models (CNRM‐CM5 and GFDL‐ESM2M), and two representative concentration pathways (8.5 and 4.5). We found little difference between management scenarios in the number, size, or severity of fires during the last three decades. With 21st‐century warming, fire activity increased rapidly, particularly after 2050, and followed nearly identical trajectories in both management scenarios. Area burned per year between 2018 and 2099 was 1,700% greater than in the last three decades (1989–2017). Large areas of forest were abruptly lost; only 65% of the original 40,178 ha of forest remained by 2098. However, forests stayed connected and fuels were abundant enough to support profound increases in burning through this century. Our results indicate that strategies emphasizing managed wildfire use, rather than suppression, will not alter climate‐induced changes to fire and forests in subalpine landscapes of western North America. This suggests that managers may continue to have flexibility to strategically suppress subalpine fires without concern for long‐term consequences, in distinct contrast with dry conifer forests of the Rocky Mountains and mixed conifer forest of California where maintaining low fuel loads is essential for sustaining frequent, low‐severity surface fire regimes. [ABSTRACT FROM AUTHOR]

Ecosystem function and stability are highly affected by internal and external stressors. Utilizing paleobotanical data gives insight into the evolutionary processes an ecosystem undergoes across long periods of time, allowing for a more complete understanding of how plant and insect herbivore communities are affected by ecosystem imbalance. To study how plant and insect herbivore communities change during times of disturbance, we quantified community turnover across the Paleocene­–Eocene boundary in the Hanna Basin, southeastern Wyoming. This particular location is unlike other nearby Laramide basins because it has an abundance of late Paleocene and Eocene coal and carbonaceous shales and paucity of well-developed paleosols, suggesting perpetually high water availability. We sampled approximately 800 semi-intact dicot leaves from five stratigraphic levels, one of which occurs late in the Paleocene–Eocene thermal maximum (PETM). Field collections were supplemented with specimens at the Denver Museum of Nature & Science. Fossil leaves were classified into morphospecies and herbivore damage was documented for each leaf. We tested for changes in plant and insect herbivore damage diversity using rarefaction and community composition using non-metric multidimensional scaling ordinations. We also documented changes in depositional environment at each stratigraphic level to better contextualize the environment of the basin. Plant diversity was highest during the mid-late Paleocene and decreased into the Eocene, whereas damage diversity was highest at the sites with low plant diversity. Plant communities significantly changed during the late PETM and do not return to pre-PETM composition. Insect herbivore communities also changed during the PETM, but, unlike plant communities, rebound to their pre-PETM structure. These results suggest that insect herbivore communities responded more strongly to plant community composition than to the diversity of species present. [ABSTRACT FROM AUTHOR]

Vegetation green-up signals the timing of available nutritious plants and shrubs providing high-quality forage for ungulates. In this study, we characterized spatial and temporal patterns of spring phenology and explored how they were related to preceding temperature and moisture conditions. We tested correlations between late winter weather and indicators of the onset and the length of the spring growing period with 250-m resolution time-series satellite data (2001 - 2013) for Wyoming, USA. In western Wyoming mountains, drier and warmer conditions during late winter were associated with earlier spring green-up onset of growth in forests, shrubs, and grasses. In the northeast mountains, onset of spring correlated positively with preceding warmer temperatures, but not with precipitation. In most basin and plains shrublands and grasslands, spring onset was not correlated with temperature, although earlier onset of spring was correlated with drier conditions in 25% of shrub/scrub areas. Results about the length of spring were less definitive, with warmer temperatures related to longer green-up time for 12-30% of the land cover in western mountains but to shorter green-up time periods for 10-20% of the grasses and shrubs in basins and plains. Complex phenological patterns are likely to affect ungulate foraging behaviour on a local scale. [ABSTRACT FROM AUTHOR]

The structure and function of grassland ecosystems can be altered by a changing climate, including higher temperature and elevated atmospheric CO2 concentration. Previous studies suggest that there is no consistent trend in seed germination and seedling recruitment as affected by these conditions. We collected seeds of two native and two invasive species over 6 years from a field study with elevated CO2 (600 p.p.m.) and temperature (1.5/3.0°C day/night) on the mixed-grass prairie of Wyoming, USA. Seed fill, viability and mass were evaluated and germination tests were conducted under alternating temperatures in growth chambers. Thermal time requirements to reach 50% germination (θ50) and base temperatures (T b) for germination were determined using thermal time models. Climate change conditions had limited effects on seed fill, viability and mass. The combination of CO2 enrichment and warming increased germination of Bouteloua gracilis. Centaurea diffusa and Linaria dalmatica , two invasive species in this study, had the lowest θ50 and T b required for germination among all the species studied. Although final germination percentages of these invasive species were not affected by treatments, previous studies reported increased seed production under future climate conditions, indicating that they could be more invasive at the regeneration stage in the future. We conclude that projected future temperature increases will have little effect on seed reproductive traits of native species. In addition, the distribution and abundance of B. gracilis and invasive species may be favoured by global climate change due to enhanced germination or seed production traits caused by elevated parental CO2 and temperature conditions. [ABSTRACT FROM AUTHOR]

Background: Spatial scale is important when studying ecological processes. The Greater sage-grouse (Centrocercus urophasianus) is a large sexually dimorphic tetraonid that is endemic to the sagebrush biome of western North America. The impacts of oil and gas (OAG) development at individual leks has been welldocumented. However, no previous studies have quantified the population-level response. Methods: Hierarchical models were used to estimate the effects of the areal disturbance due to well pads as well as climatic variation on individual lek counts and Greater sage-grouse populations (management units) over 32 years. The lek counts were analyzed using generalized linear mixed models while the management units were analyzed using Gompertz population dynamic models. The models were fitted using frequentist and Bayesian methods. An information-theoretic approach was used to identify the most important spatial scale and time lags. The relative importance of OAG and climate at the local and population-level scales was assessed using information-theoretic (Akaike's weights) and estimation (effect size) statistics. Results: At the local scale, OAG was an important negative predictor of the lek count. At the population scale, there was only weak support for OAG as a predictor of density changes but the estimated impacts on the long-term carrying capacity were consistent with summation of the local impacts. Regional climatic variation, as indexed by the Pacific Decadal Oscillation, was an important positive predictor of density changes at both the local and population level (particularly in the most recent part of the time series). Conclusions: Additional studies to reduce the uncertainty in the range of possible effects of OAG at the population scale are required. Wildlife agencies need to account for the effects of regional climatic variation when managing sage-grouse populations. [ABSTRACT FROM AUTHOR]

Cities are key sites of action for adaptation to climate change. However, there are a wide variety of responses to hazards at the municipal level. Why do communities take adaptive action in the face of weather- and climate-related risk? We studied what cities are doing in response to existing natural hazards, such as floods, droughts, and blizzards as an analog for understanding the drivers of adaptive behavior toward climate change risks. We conducted a survey of 60 U.S. municipalities followed by six in-depth case studies in the intermountain west states of Colorado, Wyoming and Utah that regularly experience weather and climate extreme events. Our analysis shows that perception of risk and external factors such as planning requirements and availability of funding stand out as important drivers. Nevertheless, political action is rarely driven by a single factor or event. Overall, our results suggest that multiple factors interact or act in combination to produce an enabling environment for action in the face of weather- and climate-related risk. [ABSTRACT FROM AUTHOR]

Ancient cultural changes have often been linked to abrupt climatic events, but the potential that climate can exert a persistent influence on human populations has been debated. Here, independent population, temperature, and moisture history reconstructions from the Bighorn Basin in Wyoming (United States) show a clear quantitative relationship spanning 13 ka, which explains five major periods of population growth/decline and ∼45% of the population variance. A persistent ∼300-y lag in the human demographic response conforms with either slow (∼0.3%) intrinsic annual population growth rates or a lag in the environmental carrying capacity, but in either case, the population continuously adjusted to changing environmental conditions. [ABSTRACT FROM AUTHOR]

Future climate projections predict warming at high elevations that will impact treeline species, but complex topographic relief in mountains complicates ecologic response, and we have a limited number of long-term studies examining vegetation change related to climate. In this study, pollen and conifer stomata were analyzed from a 2.3 m sediment core extending to 15,330 cal. yr BP recovered from a treeline lake in the Rocky Mountains of Wyoming. Both pollen and stomata record a sequence of vegetation and climate change similar in most respects to other regional studies, with sagebrush steppe and lowered treeline during the Late Pleistocene, rapid upward movement of treeline beginning about 11,500 cal. yr BP, treeline above modern between ~9000 and 6000 cal. yr BP, and then moving downslope ~5000 cal. yr BP, reaching modern limits by ~3000 cal. yr BP. Between 6000 and 5000 cal. yr BP sediments become increasingly organic and sedimentation rates increase. We interpret this as evidence for lower lake levels during an extended dry period with warmer summer temperatures and treeline advance. The complex topography of the Rocky Mountains makes it challenging to identify regional patterns associated with short term climatic variability, but our results contribute to gaining a better understanding of past ecologic responses at high elevation sites. [ABSTRACT FROM AUTHOR]

Greater sage-grouse ( Centrocercus urophasianus) are threatened by loss of sagebrush habitat and the spread of West Nile virus throughout much of their range in North America; yet, future impacts of climate change on these potential stressors have not been addressed. Here, we aim to quantify the potential impacts of climate change on the distribution of climatically suitable habitat for sagebrush and on transmission risk for West Nile virus in the eastern portion of the species' range. We used Maxent to model the current and future climatically suitable habitat for two dominant sagebrush species in the study area, and we used a degree-day model to predict future West Nile virus transmission risk under likely climate-change scenarios. Our models suggest that areas with the highest future suitability for sagebrush habitat will be found in southwestern Wyoming and north-central Montana. The degree-day model suggests that greater sage-grouse in western portions of the study area, which are generally higher in elevation than where West Nile virus currently occurs, will see increasing risk of transmission in the future. We developed a spatially explicit map of suggested management actions based on our predictions that will aid in conservation of the species into the coming decades. [ABSTRACT FROM AUTHOR]

Climate change is likely to alter wildfire regimes, but the magnitude and timing of potential climate-driven changes in regional fire regimes are not well understood. We considered how the occurrence, size, and spatial location of large fires might respond to climate projections in the Greater Yellowstone ecosystem (GYE) (Wyoming), a large wildland ecosystem dominated by conifer forests and characterized by infrequent, high-severity fire. We developed a suite of statistical models that related monthly climate data (1972-1999) to the occurrence and size of fires >200 ha in the northern Rocky Mountains; these models were cross-validated and then used with downscaled (~12 km × 12 km) climate projections from three global climate models to predict fire occurrence and area burned in the GYE through 2099. All models predicted substantial increases in fire by midcentury, with fire rotation (the time to burn an area equal to the landscape area) reduced to <30 y from the historical 100-300 y for most of the GYE. Years without large fires were common historically but are expected to become rare as annual area burned and the frequency of regionally synchronous fires increase. Our findings suggest a shift to novel fire-climate-vegetation relationships in Greater Yellowstone by midcentury because fire frequency and extent would be inconsistent with persistence of the current suite of conifer species. The predicted new fire regime would transform the flora, fauna, and ecosystem processes in this landscape and may indicate similar changes for other subalpine forests. [ABSTRACT FROM AUTHOR]

Marine and continental records show an abrupt negative shift in carbon isotope values at ?55.8?Myr ago. This carbon isotope excursion (CIE) is consistent with the release of a massive amount of isotopically light carbon into the atmosphere and was associated with a dramatic rise in global temperatures termed the Palaeocene-Eocene thermal maximum (PETM). Greenhouse gases released during the CIE, probably including methane, have often been considered the main cause of PETM warming. However, some evidence from the marine record suggests that warming directly preceded the CIE, raising the possibility that the CIE and PETM may have been linked to earlier warming with different origins. Yet pre-CIE warming is still uncertain. Disentangling the sequence of events before and during the CIE and PETM is important for understanding the causes of, and Earth system responses to, abrupt climate change. Here we show that continental warming of about 5?°C preceded the CIE in the Bighorn Basin, Wyoming. Our evidence, based on oxygen isotopes in mammal teeth (which reflect temperature-sensitive fractionation processes) and other proxies, reveals a marked temperature increase directly below the CIE, and again in the CIE. Pre-CIE warming is also supported by a negative amplification of ?13C values in soil carbonates below the CIE. Our results suggest that at least two sources of warming-the earlier of which is unlikely to have been methane-contributed to the PETM. [ABSTRACT FROM AUTHOR]

Clark, Gregory M., 2010. Changes in Patterns of Streamflow From Unregulated Watersheds in Idaho, Western Wyoming, and Northern Nevada. Journal of the American Water Resources Association (JAWRA) 46(3):486-497. DOI: 10.1111/j.1752-1688.2009.00416.x Recent studies have identified a pattern of earlier spring runoff across much of North America. Earlier spring runoff potentially poses numerous problems, including increased risk of flooding and reduced summer water supply for irrigation, power generation, and migratory fish passage. To identify changing runoff patterns in Idaho streams, streamflow records were analyzed for 26 U.S. Geological Survey gaging stations in Idaho, western Wyoming, and northern Nevada, each with a minimum of 41 years of record. The 26 stations are located on 23 unregulated and relatively pristine streams that drain areas ranging from 28 to >35,000 km2. Four runoff parameters were trend tested at each station for both the period of historical record and from 1967 through 2007. Parameters tested were annual mean streamflow, annual minimum daily streamflow, and the dates of the 25th and 50th percentiles of the annual total streamflow. Results of a nonparametric Mann-Kendall trend test revealed a trend toward lower annual mean and annual minimum streamflows at a majority of the stations, as well as a trend toward earlier snowmelt runoff. Significant downward trends over the period of historical record were most prevalent for the annual minimum streamflow (12 stations) and the 50th percentile of streamflow (11 stations). At most stations, trends were more pronounced during the period from 1967 through 2007. A regional Kendall test for water years 1967 through 2007 revealed significant regional trends in the percent change in the annual mean and annual minimum streamflows (0.67% less per year and 0.62% less per year, respectively), the 25th percentile of streamflow (12.3 days earlier), and the 50th percentile of streamflow (11.5 days earlier). [ABSTRACT FROM AUTHOR]

Aim Fire suppression, elk (Cervus elaphus Erxleben) browsing and drought have been suggested as possible explanations for low aspen (Populus tremuloides Michx.) ramet regeneration in elk winter range of the Greater Yellowstone Area (GYA) during the twentieth century. This study analyses the relationship between the rates of aspen regeneration, biophysical factors and human land use since 1830. This approach reveals the importance of indirect human impacts, especially through fire and elk management strategies, on forest structure. Location This study was conducted in and around the winter range of the Jackson Hole elk herd in western Wyoming, USA. Aspen stands in this region represent the ecotone between coniferous forest and sagebrush-grassland vegetation. Methods Age structures of aspen stands were reconstructed from tree-rings in order to determine how variation in drought, elk populations and fire occurrence may have affected aspen ramet regeneration since 1830. The effects of recent prescribed fires and elk browse on aspen regeneration were also evaluated by measuring stem height, browse intensity and age of ramets <2 m tall in prescribed burns and in unburned areas. Results Aspen ramet regeneration has occurred consistently but at low frequencies since 1830, with three peaks of regeneration: 1860–85, 1915–40 and 1955–90. Periods of frequent ramet regeneration coincided with low to moderate elk populations and aspen regenerated only sporadically when elk populations were high. Based on a comparison of the age structures with a tree-ring reconstruction of Palmer drought severity index (PDSI), observed PDSI and annual precipitation, drought variability appears unrelated to episodes of aspen regeneration. Recent regeneration patterns suggest that fire does not enhance the recruitment of tree-sized aspen stems in the presence of elk browse, although sample sizes were small. Since 1900, elk hunting and spatially clustered elk feeding in the... [ABSTRACT FROM AUTHOR]