The majority of interior cutthroat trout (Oncorhynchus clarki) subspecies have been extirpated from large rivers by anthropogenic activities that have fragmented habitats and introduced non-native competitors. Selective pressures against migratory behaviors and mainstream river occupation and conservation schemes that isolate genetically pure populations above barriers have restricted gene flow and prevented the expression of fluvial life history traits in many populations. Existing knowledge about the movements and home range requirements of fluvial cutthroat trout is therefore limited. We implanted a total of 55 Bonneville cutthroat trout (BCT) in the Thomas Fork River, Idaho, with radio transmitters and located them weekly or bimonthly from October to April of both 1999/2000 and 2000/2001. Half of these fish were located above a seasonal diversion barrier and half were located below. We found fish to be more mobile than previously reported. Individuals located above the diversion barrier in 2000/2001 occupied significantly larger home ranges (median 3,675 m, range 2,500-8,900 m) and moved more frequently (mean 0.89 movements/contact, range 0.57-1.0) than other fish. Fish occupied habitats in the lower Thomas Fork and Bear River during the winter that were marginal or uninhabitable during other seasons. During the spring of both years we located fish in both upstream and neighboring tributaries up to 84 km away from our study site. Our results document the existence of a fluvial component of BCT in the Bear River and its tributaries and suggest that successful efforts at conservation of these fish will focus on mainstream habitats and the maintenance of seasonal migration corridors.

My research focused on common raven (Corvus corax; hereafter raven) winter ecology and removal, and how raven removal aids Greater sage-grouse (Centrocerus urophasiansu; hereafter sage-grouse) populations. Raven winter ecology in the western US has not been described in detail. I researched raven use of landfills for foraging and raven use of anthropogenic structures for roosting, as well as dispersal of ravens in the spring. In all 22% of radio-marked ravens (n=73) used landfills during the day, and 68%(n=73) roosted at anthropogenic roost sites during the evening. Correlations between landfill and roost counts of ravens were stronger (0.4>r<0.7) when the distance between these sites was <15 km, and smaller (r<0.3) when this distance >20 km. In the spring, ravens dispersed, on average, 38 km from landfills where they were caught. Large congregations of ravens at a few sites in winter may present opportunities to initiate raven population reduction methods to alleviate later problems. I analyzed raven survival and behaviour when USDA/APHIS Wildlife Services (WS) removed ravens using DRC-1339 during winter months. The number of ravens killed annually was 7-34% of the local population. Ravens did not avoid landfills, yet they switched roosts more frequently after an application of the toxicant. Raven removal improves sage-grouse nest success; however, data were not available to examine how raven removal improves sage-grouse abundance. I analyzed changes in raven density with regard to WS removal, and then related these changes with changes in sage-grouse lek counts the following year. Raven densities decreased by 50% from 2008-2014 where WS conducted removal programs. Sage-grouse lek counts improved in area where WS lowered raven abundance, in comparison to areas farther away, during the latter half of the study (2013-2015), when WS removal efforts intensified. Thereafter, a 10% decline in raven abundance was associated with a 2% increase in sage-grouse lek counts. Overall, ravens in souther Wyoming used anthropogenic resources during the winter, and removal of ravens at these locations, combined with removal in the spring, minimally impacted raven populations annually and was associated with increases in sage-grouse abundance.

An intensive creel census and marking program was conducted in 1969 and 1970 to make possible population estimates and estimates of harvest of cutthroat trout in the Snake River in Teton County, Wyoming. Stock density determinations made in one of the five study areas provided an estimate of 400 and 992 cutthroat trout, eight inches or more in length, per mile of stream in 1969 and 1970 respectively. Harvest data provide an estimate of 5,207 and 5,903 cutthroat trout harvested in 1969 and 1970 respectively. The harvest estimates obtained in this study are not comparable to those made in 1967 and 1968 due to a difference in the methods used in obtaining these data. The catches of cutthroat trout per hour in 1969 and 1970 were calculated to be 0.31 and 0.30 respectively, These relatively low success rates are coincident with the fluctuating volume flows of the Snake River. Average lengths, condition factors, and catch per unit effort do not indicate significant changes in the fishery from past years.

A study was initiated in 1981 to investigate the redevelopment of plant communities on a recontoured, surface-mined site in southwestern Wyoming. The landscape pattern of vegetation was compared with topographic position, the initial topsoil pattern, and cultural practices including shrub planting density, shrub planting pattern and topsoil treatments for the years 1982-1985. In addition, differences in vascular plant species diversity within these various factors and treatments were determined, along with the trend in intracommunity (alpha), intercommunity (beta) and landscape (gamma) diversity for the entire study area. The influence of site factors and tested cultural practices on the differentiation of the landscape vegetation pattern generally declined over time. There were no persistent differences in diversity among any cultural treatments or topographic positions, with the exception of plan ting pattern. The vegetation classified by cultural treatment, topographic position, or the initial plant comm uni ties identified in 1982 showed strong successional convergence by 1985. This is reflected in a decline in be ta and gamma diversity over the period 1984-1985. Alpha diversity remained stable over this same period, though species richness increased, indicating that a subset of species is becoming more dominant. The landscape vegetation pattern apparently converged to a rather uniform composition, increasingly dominated by perennial grasses, forbs and shrubs.

Herbivory and plant competition affect sexual reproduction of plants in various ways. Exclusion of mule deer (Odocoileus hemionus) and cattle, removal of plant competition (both inter- and intraspecific), and all combinations of the above treatments were used to examine the individual and combined affects on Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) reproduction. Reproduction of Artemisia tridentata ssp. wyomingensis was divided into hierarchical levels of the number of: (1) modules per current-year ' s growth (CYG), (2) nodes per module, (3) inflorescence heads per node, (4) achenes per inflorescence head and (5) percent viable achenes. Counts at hierarchical levels were made to determine the level affected by the treatments. Deer herbivory significantly reduced reproduction at the reproductive-module-per-CYG-vegetative-biomass hierarchical level, while plant competition (both inter- and intraspecific) significantly reduced reproduction at the nodes-per-reproductive-module level and at the inflorescence-heads-per-node level. Cattle presence had neither a beneficial nor detrimental influence on reproduction during this two-year study. The combined effects of release from deer herbivory and from plant competition on reproduction was more than additive because these biotic interactions affected nested hierarchical levels.

Plant spatial patterns have been studied to gain insight into plant interactions such as competition and facilitation (positive plant interactions). The stress gradient hypothesis predicts that as environmental stress increases facilitation dominates, while competition dominates in less stressful conditions. Beneficial plants (nurses) can create favorable abiotic conditions for subanopy plants. Additionally, palatable herbaceous species growing under nurse shrub canopies benefit from physical protection. I investigated spatial associations between Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) and three native grasses (Poa secunda, Elymus elymoides, and Pseudoroegneria spicata) across a rainfall gradient in the Great Basin, USA. I also explored the effect of grazing on grass-shrub spatial associations. I hypothesized that positive shrub-grass spatial associations would become more frequent at lower rainfall levels; I further hypothesized that 1) at intermediate levels of stress, positive grass-shrub spatial associations would dominate and 2) at extreme levels of stress, positive grass-shrub spatial associations and interactions would no longer dominate. At high moisture stress, the addition of grazing stress may limit the nurse’s ability to provide to benefits to subcanopy plants. Cover of P. secunda was greater in shrub canopy microsites than interspaces at low to moderate levels of rainfall. Cover and density of E. elymoides were greater in sagebrush canopies over most rainfall levels. Elymus elymoides and P. spicata were taller and narrower in basal width and less likely to be grazed in canopy versus interspace microsites. I next investigated the effects of grazing intensity over a rainfall gradient and found a significant interaction of rainfall and microsite on P. secunda cover. Poa secunda formed positive interactions with A. tridentata at lower rainfall levels, regardless of grazing intensity. Its cover was significantly greater in interspaces at high rainfall compared to low rainfall sites. Elymus elymoides density was greater in canopy vs. interspace microsites, regardless of rainfall level or grazing intensity. Plant spatial associations can indicate which nurse microsites are favorable to plant growth and may improve seeding or planting success during ecological restoration. My results suggest that exploiting sagebrush canopy microsites for restoration of native perennial grasses would improve plant establishment, growth or survival particularly in drier areas.

Holocene climate likely influenced prehistoric hunter-gatherer subsistence and mobility as changing climate patterns affected food resources. Of interest here is whether climate-driven resource variability influenced peoples in the central Rocky Mountains. This study employed the z-score model to predict how foragers coped with resource variability. The exercise enabled exploration of the relationship between climate, resources, and foraging strategies at High Rise Village (48FR5891), an alpine residential site in Wyoming's Wind River Range occupied between 2800-250 cal B.P. The test was applied to occupations dating to the Medieval Warm Period (1150-550 cal B.P.) and the Little Ice Age (550-100 cal B.P.). Using regional characterizations of temporal variability for these climate periods, a z-score model was employed to develop predictions of how foragers coped with resource variability and predictability during both periods. The model predicted foraging decisions at High Rise Village that managed the risk of caloric shortfall during the slow-changing Medieval Warm Period and the highly variable Little Ice Age. Predictions for each period were tested against corresponding archaeological expectations for subsistence remains, mobility and technology requirements, and the frequency of site use. Further, this study employed a dendroclimatological study to locally characterize the climate periods and test model assumptions of their contrasting patterns of variability. The dendroclimatological study corroborates model assumptions and finds that the Medieval Warm Period was a period of multidecadal climatic variability and resource predictability while the Little Ice Age was characterized by short-term variability and resource unpredictability. Poor preservation of subsistence remains hampered the archaeological study. However, as expected, lithic and chronometric data indicate the site was used residentially and relatively frequently during the Medieval Warm Period, and that use decreased during the Little Ice Age. Medieval use of the site appears to be by Uinta Phase (1800-900 cal B.P.) foragers from the adjacent lowlands, and likely related to regional population pressure, as well as resource accessibility and predictability at High Rise Village. A dramatic decrease in site use predates the Little Ice Age and is likely related to regional population decrease and not LIA conditions at High Rise Village.

The objectives of this study were to determine how seed reserves varied with depth in topsoil stockpiles and to evaluate the effect of length of time of storage on the number of viable seeds and number of species of seeds. Soil samples were taken from five topsoil piles representing zero to three years of storage on the Elkol-Sorenson mine near Kemmerer in southwestern Wyoming. Seeds were extracted using flotation/separation methods and were tested for viability using 2,3,5-triphenyl tetrazolium chloride solution. Data were analyzed using nonparametric statistical tests. Overall density of seeds in topsoil piles was low. No relationship was found between depth into the topsoil pile and the number of seeds or species. The number of seeds and species in the topsoil pile showed no decrease with increasing length of time of storage. The proportion of annual species in the seed reserve was not shown to increase with length of time of storage. Comparisons were made between the species composition of the seed reserve in the topsoil piles and the species composition of vegetation on sites selected to represent the sites of origin of the topsoil. Factors affecting the density, species composition and species richness of stored topsoil were suggested to be the plant community on the soil to be removed, depth of soil removed, and timing of topsoil removal.

The landscape evolution of the northeastern Uinta Mountains and the manner in which climatic and tectonic forcing have influenced it are not well constrained. Surficial deposits covering ~325 km2 below the glacial termini in the Henrys Fork and ~50 km2 along the Green River in western Browns Park were mapped at 1:24,000 scale to develop a Quaternary stratigraphic framework for the northeastern Uinta Mountains. The Henrys Fork mapping area spans from late Wisconsinan moraines to Flaming Gorge Reservoir. The Henrys Fork stratigraphy contains 10 mainstem gravels, six piedmont gravels, and landslide deposits. Terraces preserved along the Henrys Fork converge downstream and are strath terraces underlain by clast-supported, cobble gravel derived from the Uinta Mountain Group and Paleozoic limestone units. The Henrys Fork terrace stratigraphy was correlated to the Wind River terrace stratigraphy for age control, and incision rates were estimated at 80-110 m/m.y. The Browns Park mapping area includes Little Hole and continues through lower Red Canyon into westernmost Browns Park, ending at the Warren Draw-Swallow Canyon quadrangle boundary. The Browns Park stratigraphy includes eight mainstem gravels, five piedmont gravels, and various landslide, colluvial, and eolian deposits. A tuffaceous bed with Lava Creek Bash (640 ka) was identified near the top of a deposit at Little Hole that was previously mapped as Miocene basin fill. Minimum Green River incision rates were estimated between 90 and 115 m/m.y. using the Lava Creek Bash for age control. These rates are comparable to estimates for the Henrys Fork, but are about half of the rates reported for the south flank of the Uintas and other central Rocky Mountain ranges. A series of three distinct deposits in western Browns Park are interpreted as evidence for the landslide impoundment and subsequent outburst flooding of the Green River. These include slackwater deposits at Little Hole, an outburst flood deposit in western Browns Park, and a large paleolandslide deposit that lies between them. Estimates of sediment accumulation rates behind the paleolandslide dam suggest it was stable for ~605 years. Peak discharge estimates from impounded water volume estimates and paleoflow competence indicators suggest that the resulting outburst flood was ~22,000 m3/s.

A detailed study was made of the composition and distribution of modern and fossil animal and plant traces around saline, alkaline lakes in tectonically active, closed lake-basins. Modern and Pleistocene traces that were examined in lake basins of the Kenya Rift Valley (Lakes Bogoria, Magadi, and Nasikie Engida) were compared directly with fossil traces from the Eocene Lake Gosiute in the Green River Formation of Wyoming, U.S.A., which had a similar hydrochemistry. Analysis of lithofacies and the stratigraphic packaging of the sediments hosting biogenic structures was undertaken so that their vertical and lateral distribution could be used to interpret lake histories and to help to develop depositional models of enigmatic sedimentary successions. A focus was given to the application of the results for paleoecology and stratigraphy, and a model for predicting the position of different trace associations in vertical successions and in different parts of saline, alkaline lake basins has been developed. Evidence from the Kenyan lakes and Eocene Lake Gosiute shows that (1) sedimentary environments are diverse in underfilled basins, and frequent lake-level fluctuations strongly impact the distribution of sedimentary environments suitable for the production and preservation of biogenic structures; (2) the distribution of biogenic structures in underfilled basins is related to the geomorphological and structural setting, tectonic activity, catchment lithology, the basin margin or basin centre location, climate, and salinity and alkalinity, together with other finer-scale environmental and biological controls; (3) because saline environments are restrictive, sites of relatively dilute inflow (springs, rivers and deltas, ephemeral streams) provide oasis-like habitats for animals and plants, and contribute to the increased diversity and laterally variable distribution of saline-lake trace assemblages; and (4) the vertical distribution of trace fossils in a stratigraphic succession reflects changing environments through time; important stratigraphic surfaces, usually formed during periods of lake-level fall, can be recognized from the overprinting patterns of traces produced under different conditions.