Habitat use and selection and home ranges of Merriam's Wild Turkey in Oregon

Habitat use and selection by Merriam's Wild Turkeys ( Meleagris gallopavo merriami ) in Wasco County, Oregon, was studied during 1981-82. This turkey population selectively used forested cover types (such as ponderosa pine-Douglas-fir-oak, ponderosa pine-oak) characterized by a variety of structural features, species, and age classes. The population used single species forested cover types (oak, ponderosa pine) less than expected, used nonforested cover types in proportion to their availability, and avoided forested cover types with structure simplified by logging activities. The four age and sex classes had large seasonal home ranges (￣x = 1,615 ha); the smallest home ranges were exhibited by adult males in winter and the largest were shown by subadult males in fall. In most instances, turkeys used cover types as they were available. We suggest that structural complexity of vegetation, both within and among cover types, is an important component of habitat for Merriam's Wild Turkeys that should be considered in the evaluation of potential release sites and in habitat management plans.     

Increased willow heights along northern Yellowstone's Blacktail Deer Creek following wolf reintroduction

Gray wolves ( Canis lupus ) were reintroduced into Yellowstone National Park in 1995–1996. In August 2004 we measured plant architecture of Geyer willow ( Salix geyeriana ) stems along three 100-m reaches of Blacktail Deer Creek in Yellowstone's northern elk ( Cervus elaphus ) winter range to evaluate changes in patterns of browsing and height growth following wolf reintroduction. Average browsing intensities ( n = 3 stream reaches) of 100% in 1997 decreased to 0%–55% by 2003, whereas average stem heights of 25–74 cm in 1997 increased to 149–268 cm by 2003, indicating that willow height growth was inversely related to browsing intensity. In addition, average willow canopy cover over the streams increased from < 5% in 1997 to 14%–73% in 2004. These findings were consistent with a hypothesis that increased willow heights following the 1995–1996 wolf reintroduction represent a trophic cascade involving wolves, elk, and deciduous woody vegetation.     

Gray fox and coyote abundance and diet responses after a wildfire in central Arizona

There is a paucity of information on the effects of wildfire on carnivores. We studied the effects of a 237-km 2 catastrophic wildfire in the Mazatzal Mountains, Arizona, on gray foxes ( Urocyon cinereoargenteus ) and coyotes ( Canis latrans ). We indexed relative abundance 3 times each year from 1996 to1998 using scat transects in burned and unburned areas. We collected scats to estimate diet and measured small mammal abundance and mast availability in 1997 and 1998. We also measured vegetation cover in burned and unburned sites. Gray fox indices declined 3 months postfire, but after 30 months, indices returned to preburn levels. Coyote indices did not change. Primary foods for both species in burned and unburned sites were mast (fruits of shrubs) and rodents, and diet comparisons between sites became similar as plant succession continued. Scat indices did not correlate with seasonal small mammal abundance. We suspect that the lower abundance indices of gray foxes were related to reduction in cover and food availability, because indices increased as vertical cover and mast crop increased. These data indicate that the effects of this catastrophic fire were short-term but also highlight the importance of preserving shrub and vegetation diversity for gray fox.     

Vegetation responses to 35 and 55 years of native ungulate grazing in shrubsteppe communities

Ungulate populations are managed in shrubsteppe ecosystems around the world, but relatively few long-term datasets are available that test the impacts of these grazers on shrubsteppe structure and function. This study evaluated 8 exclosures in 4 shrubsteppe communities to determine the effects of deer and elk over 35 or 55 years on (1) plant biomass and species composition, (2) soil nitrogen (N) mineralization and net nitrification rates, Olsen extractable phosphorus (P), and C:N ratios, and (3) arthropod diversity and abundance. The site with deer, the highest ungulate densities, and coldest climate (Sinlahekin Wildlife Area, WA) had greater vegetative biomass and cover inside the exclosures than outside. The sites with elk, moderate ungulate densities, and intermediate climatic conditions (Oak Creek and Wenas Wildlife Areas, WA) had no effects of exclosures on vegetative biomass or cover. The site with elk, the lowest ungulate densities, and driest climatic conditions (L.T. Murray Wildlife Area, WA) had greater shrub cover outside of the exclosures. Ungulates significantly increased net N mineralization and nitrification rates, providing a potential explanation for compensatory growth by grazed plants. Our data suggest that arthropod herbivory does not substitute for ungulate herbivory. To the contrary, arthropod diversity reflected ungulate-induced changes in plant biomass. In addition to effects on standing biomass, ungulates were associated with increased exotic plant species richness at all 4 sites. Our results suggest that there may be a balance between indirect positive and direct negative effects of herbivory on plants that varies with ungulate densities and site characteristics, and that arthropod herbivory does not functionally replace ungulate herbivory.     

Great Basin summer range forage quality: do plants nutrients meet elk requirements?

Understanding the relative ability of forages to meet the needs of prime-age females, the productive component of elk ( Cervus elaphus ) populations, is necessary to decipher reasons for declines and potential for population growth. Information on forage nutrient dynamics for elk on Great Basin summer-fall ranges is lacking. Our primary objectives were to estimate nutrient levels in common elk forage species in northeastern Nevada at 3 time periods and evaluate whether nutrient levels met good requirements for lactating cow elk at time periods across summers. We compared crude protein, digestible energy, and macromineral levels in 2 forbs, 6 grasses, and 4 woody browse forage species to requirements for lactating cow elk in early summer, midsummer, and early fall 1999 and 2000. Spurred lupine ( Lupinus caudatus ) and snowbrush ceanothus ( Ceanothus velutinus ) were the most proteinaceous plants, exceeding requirements across all seasons. By midsummer, protein levels in all grasses were below elk requirements (12%). Digestible energy was the most limiting nutrient with woody browse meeting lactating cow elk requirements only in early fall (2750 kcal · kg -1 ). Sodium levels never exceeded about 10% of the required 600 μg · g -1 . The potential for maintaining a relatively high density of elk at forage-quality levels that fulfill requirements declines as summers progress on Great Basin summer ranges. Maintaining highly productive elk herds in the Great Basin requires that managers maintain plant communities with a diversity of forbs, grasses, and browse to provide for nutritional needs of lactating cows and their growing calves.     

Ungulate herbivory on alpine willow in the Sangre de Cristo Mountains of Colorado

In many areas of the Rocky Mountains, elk ( Cervus elaphus ) migrate from low-elevation mountain valleys during spring to high-elevation subalpine and alpine areas for the summer. Research has focused on the impacts of elk herbivory on winter-range plant communities, particularly on woody species such as willow and aspen; however, little information is available on the effects of elk herbivory on alpine willows. In the Sangre de Cristo Mountains of south central Colorado, select alpine areas appear to receive high levels of summer elk herbivory, while other areas are nearly unbrowsed. In 2005 and 2008, we measured willow height, cover, and utilization on sites that appeared to be used heavily by elk, as well as on sites that appeared to be used lightly, to determine differences between these communities over time. We found less willow cover and shorter willows at sites that received higher levels of browsing compared to those that had lower levels of browsing. Human recreational use was greater at lightly browsed sites than at highly browsed sites. From 2005 to 2008, willow utilization declined, and willow cover and height increased at sites with heavy browsing, likely owing to ownership change of adjacent valley land which led to (1) removal of grazing competition from cattle at valley locations and (2) increased human use in alpine areas, which displaced elk. We discuss the implications of increased human use and climate change on elk use of these alpine habitats. En muchas &aacute;reas de las Monta&ntilde;as Rocosas, el ciervo rojo ( Cervus elaphus ) migra durante la primavera de valles monta&ntilde;osos de baja elevaci&oacute;n a &aacute;reas altas subalpinas y alpinas para el verano. Hasta ahora la investigaci&oacute;n se ha enfocado en el impacto de la herbivor&iacute;a del ciervo rojo sobre las comunidades de plantas en el invierno, particularmente en las especies le&ntilde;osas como el sauce y el &aacute;lamo; sin embargo, existe poca informaci&oacute;n disponible sobre el efecto de la herbivor&iacute;a del ciervo rojo en los sauces alpinos. En la cordillera Sangre de Cristo al centro-sur de Colorado, ciertas &aacute;reas alpinas parecen tener altos niveles de herbivor&iacute;a de verano por el ciervo rojo, en tanto que otras &aacute;reas quedan casi sin ramoneo. En 2005 y 2008 medimos la altura, cobertura y uso de los sauces en sitios en los que parec&iacute;a haber sido abundante el ramoneo y los comparamos con sitios donde parec&iacute;a haber sido m&aacute;s ligero, a fin de determinar las diferencias entre estas comunidades en el tiempo. Encontramos menos cobertura y altura de sauces en los sitios que recib&iacute;an niveles m&aacute;s altos de ramoneo en comparaci&oacute;n a los que ten&iacute;an menos evidencia de ello. El uso humano recreativo era mayor en los sitios de ramoneo ligero que en donde era abundante. De 2005 a 2008, disminuy&oacute; el uso y aument&oacute; la cobertura y la altura en sitios de ramoneo abundante, probablemente debido a que un valle adyacente cambi&oacute; de propietario, lo cual provoc&oacute; (1) la eliminaci&oacute;n de la competencia por el pastoreo en ganado en el valle; y (2) un aumento del uso humano en &aacute;reas alpinas, desplazando al ciervo rojo. Discutimos las implicaciones del aumento del uso humano y el cambio clim&aacute;tico en el uso por el ciervo rojo de estos h&aacute;bitats alpinos.     

Summer habitat use by Columbian Sharp-tailed Grouse in western Idaho

We studied summer habitat use by Columbian Sharp-tailed Grouse ( Tympanuchus phasianellus columbianus ) in western Idaho during 1983-85. Vegetative and topographic measurements were recorded at 716 locations of 15 radio-tagged grouse and at 180 random sites within the major vegetation/cover types in the study area. The mean size of summer home ranges was 1.87 ± 1.14 km 2 . Of eight cover types identified in the study area, individual grouse used the big sagebrush Artemisia tridentata ) cover type more than or in proportion to availability, the low sagebrush ( A. arbuscula ) in proportion to availability, and avoided the shrubby eriogonum ( Eriogonum spp.) type. Characteristics of the big sagebrush cover type that Sharp-tailed Grouse preferred include moderate vegetative cover, high plant species diversity, and high structural diversity. Grouse used areas of dense cover (i.e., mountain shrub and riparian cover types) primarily for escape cover. Compared with random sites, grouse selected areas with (1) greater horizontal and vertical cover, (2) greater canopy coverage of forbs typically decreased by livestock grazing, (3) greater density and canopy coverage of arrowleaf balsamroot ( Balsamorhiza sagittata ), and (4) greater canopy coverage of bluebunch wheatgrass ( Agropyron spicatum ) in the big sagebrush cover type in 1984 and the low sagebrush cover type in 1985. The importance of the native perennials arrowleaf balsamroot and bluebunch wheatgrass became apparent during a drought year when many exotic annuals dried up and provided no cover. Overall, grouse selected vegetative communities that were least modified by livestock grazing.     

Vegetal responses and big game values after thinning regenerating lodgepole pine

Understory vegetal response was found to significantly increase with the degree of thinning in an early regenerating, dense stand of lodgepole pine ( Pinus contorta ). The value of the increased vegetation for deer and elk was determined to be important through comparisons with known dietary and habitat preferences.     

Effects of browsing by native ungulates on the shrubs in big sagebrush communities in Yellowstone National Park

The effects of elk ( Cervus elaphus ), pronghorn ( Antilocapra americana ), and mule deer ( Odocoileus hemionus ) browsing on shrubs in big sagebrush ( Artemisia tridentata ) communities were monitored over a 31-year period in Yellowstone National Park. Ungulates were restricting Wyoming big sagebrush (spp. wyomingensis ) heights, size, and recruitment on the lower-elevation stratum only, while no such suppression was observed on the high-elevation stratum. Parallel increases in mountain big sagebrush (spp. vaseyana ) densities and cover occurred over the study period on both browsed and unbrowsed sites at the higher-elevation stratum, although big sagebrush, green rabbitbrush ( Chrysothamnus viscidiflorus ), and horsebrush ( Tetradymia canescens ) were slightly taller and crown sizes were slightly larger on unbrowsed than browsed sites. Wyoming big sagebrush utilization (percent leader use) was eight times higher (￣ x = 87 ± 7.2% by pronghorns, mule deer, and elk) on the low-elevation winter ranges stratum (the Boundary Line Area [BLA] portion of the winter range), while mostly mountain big sagebrush with leader use averaged only 11 ± 4.1% (nearly all by elk) on the high-elevation range stratum. In addition, annual aboveground biomass production of big sagebrush did not differ between browsed and unbrowsed study sites on the high-elevation stratum of the winter range. Population turnover was higher on browsed plots versus unbrowsed plots. No difference was observed in percent dieback of big sagebrush adult plants between browsed and unbrowsed plots at the higher stratum. Browsing did not influence the number of leaves or seedstalks per plant ( P > .05), but leaves averaged 45% longer and seedstalks 42% longer on browsed big sagebrush. Ungulate browsing, however, apparently suppressed production, germination, and survival of Wyoming big sagebrush on the low-elevation stratum. Numbers of Wyoming big sagebrush declined 43% and cover declined 29%, 1957-1990, on browsed sites on the BLA. Annual biomass production on browsed sites at the low-elevation stratum was only 6-35% that of unbrowsed sites, and big sagebrush recruitment was less on browsed sites. Percent leader use of big sagebrush did not differ between the period of ungulate reductions, 1962-1969, and the 1980s on the lower stratum (￣ x = 87% leader use), but utilization was less on higher portions of the winter range during the period of elk reductions (￣ x = 2%) than during the 1980s following cessation of elk controls (￣ x = 11%).     

Space use by two arboreal rodent species in a Neotropical cloud forest

Studying animal space use patterns can help increase our understating of ecological processes such as competition and community dynamics. To quantify space and habitat use in an isolated and patchy cloud forest community in Mexico, we evaluate the vertical stratification, home range and habitat selection of two arboreal rodents: Habromys schmidlyi and Reithrodontomys microdon. Using live-traps at ground level and different forest strata, we radio-equipped nine individuals of H. schmidlyi and seven of R. microdon, and evaluated fine-scale space use and broad-scale habitat selection between cloud forest and oak forest. We found an average home range of 0.24 ha for R. microdon males and 0.72 ha for females, with a preference for higher canopy in the cloud forest. For H. schmidlyi the home range was 0.83 ha for males and 0.29 ha for females, with a preference for the understory level in the cloud forest. Home range is three-dimensional for these rodents, so we estimate that on average, individuals of both species used eight trees in the time they were tracked. We characterised the vegetation at the trap sites, and used recursive partitioning to relate the presence of different plants with the probability of finding these two species and Peromyscus aztecus, a third rodent species also present in the area and considered in our analysis of habitat use. The highest probability of finding R. microdon (96%) was related to the presence of Brachythecium occidentale and Renauldia mexicana, while H. schmidlyi (95%) was found in close proximity to Fabronia ciliaris and Everniastrum. We highlight the importance of arboreal trapping in biodiversity assessments, and the role of arboreal rodents in maintaining tropical forest ecosystems. We suggest that these rodent species could avoid or reduce competition by using the vertical strata differentially, and that H. schmidlyi and R. microdon can be biological indicators for cloud forest management and conservation.     

Brood-rearing habitat use by Rio Grande Wild Turkeys in Oregon

Wild turkey ( Meleagris gallopavo ) brood-rearing sites have been described for portions of their range, but brood-rearing habitat use and characteristics of brood-rearing sites used by Rio Grande Wild Turkeys ( M. g. intermedia ) in the Pacific Northwest were unknown. We described cover types at 362 brood-rearing sites and measured habitat characteristics at 64 of these sites used by a recently established Rio Grande Wild Turkey population in southwestern Oregon during May-September 1989 and 1990. Hens with broods used 9 of 10 available cover types. Meadows, mixed hardwood/conifer woodlands, and savannas were used more often than expected (47% of observations, P ≤ 0.05). Broods used mature mixed conifer and dense sapling/pole mixed conifer cover types less than expected and did not use brush-fields. Many brood-rearing sites were characterized by a parklike appearance. Understory vegetation averaged P ≤ 0.05). We suggest that land managers maintain mixed hardwood/conifer woodland and savanna cover types adjacent to meadows on south slopes to provide brood-rearing habitat for Rio Grande Wild Turkeys in southwestern Oregon.     

Natural variability of vegetation, soils, and physiography in the bristlecone pine forest of the Rocky Mountains

Pinus aristata Engelm. forest vegetation in Colorado was studied to determine vegetation composition and the relationship between vegetation and environment. Species percent cover, tree size class, and environmental variables were recorded for 49 plots. Previously collected data for 4 plots form New Mexico were included. Environmental variables included latitude, longitude, elevation, slope, aspect, topographic position, parent material, percent rock cover, mean rock size, litter depth, estimated plot age class, and evidence of anthropogenic disturbance. Soils were analyzed for texture, depth, and percent carbon and nitrogen. Pinus aristata foliage was analyzed for percent nitrogen and phosphorus. Direct and indirect gradient analyses (CANOCO) were used to determine environmental factors associated with community composition. Vegetation in P. aristata forests is influenced primarily by elevation and soil pH. Substrate, soil texture, topographic position, and geographic location are secondary factors. Six plant associations were identified using cluster analysis (listed in an elevational sequence from low to high): Pinus aristata/ Festuca arizonica Vasey, Pinus aristata / Festuca thurberi Vasey, Pinus aristata / Juniperus communis L., Pinus aristata / Vaccinium myrtilus L., Pinus aristata / Ribes montigenum McClatchie, and Pinus aristata / Trifolium dasyphyllum Torr. & Gray.     

Soil depth effects on Chihuahuan Desert vegetation

We evaluated relationships between soil depth and vegetation standing crop components over a 3-year period on 3 adjoining pastures with similar size, vegetation, and soils on the Chihuahuan Desert Rangeland Research Center in south central New Mexico. Soils on our study pastures are primarily light sandy loams varying from a few centimeters to 1 m or more in depth underlain by a calcium carbonate layer. Study pastures were ungrazed in 1995 and 1996 and conservatively grazed in 1997. Linear regression equations using perennial grass standing crop (kg ha -1 ) and honey mesquite ( Prosopis glandulosa Torr.) cover (%) as dependent variables and soil depth as the independent variable were significant ( P P = 0.78, n = 18), but a significant ( P = 0.01) negative correlation occurred on deep soils ( r = -0.67, n = 15). Perennial grass standing crop differed greatly among years when data were pooled across pastures, ranging from 64 kg ha -1 in 1995 to 248 kg ha -1 in 1997. Our study shows that soil depth has a major influence on Chihuahuan Desert vegetation. Perennial grasses are favored by shallow sandy soils while deep sandy soils favor honey mesquite.     

Habitat features and predictive habitat modeling for the Colorado chipmunk in southern New Mexico

Two subspecies of Colorado chipmunk (state threatened and federal species of concern) occur in southern New MeXico: Tamias quadrivittatus australis in the Organ Mountains and T. q. oscuraensis in the Oscura Mountains. We developed a GIS model of potentially suitable habitat based on vegetation and elevation features, evaluated site classifications of the GIS model, and determined vegetation and terrain features associated with chipmunk occurrence. We compared GIS model classifications with actual vegetation and elevation features measured at 37 sites. At 60 sites we measured 18 habitat variables regarding slope, aspect, tree species, shrub species, and ground cover. We used logistic regression to analyze habitat variables associated with chipmunk presence/absence. All (100%) 37 sample sites (28 predicted suitable, 9 predicted unsuitable) were classified correctly by the GIS model regarding elevation and vegetation. For 28 sites predicted suitable by the GIS model, 18 sites (64%) appeared visually suitable based on habitat variables selected from logistic regression analyses, of which 10 sites (36%) were specifically predicted as suitable habitat via logistic regression. We detected chipmunks at 70% of sites deemed suitable via the logistic regression models. Shrub cover, tree density, plant proximity, presence of logs, and presence of rock outcrop were retained in the logistic model for the Oscura Mountains; litter, shrub cover, and grass cover were retained in the logistic model for the Organ Mountains. Evaluation of predictive models illustrates the need for multi-stage analyses to best judge performance. Microhabitat analyses indicate prospective needs for different management strategies between the subspecies. Sensitivities of each population of the Colorado chipmunk to natural and prescribed fire suggest that partial burnings of areas inhabited by Colorado chipmunks in southern New Mexico may be beneficial. These partial burnings may later help avoid a fire that could substantially reduce habitat of chipmunks over a mountain range.     

Bottom-up factors influencing riparian willow recovery in Yellowstone National Park

After the elimination of wolves ( Canis lupis L.) in the 1920s, woody riparian plant communities on the northern range of Yellowstone National Park (YNP) declined an estimated 50%. After the reintroduction of wolves in 1995&ndash;1996, riparian willows ( Salix spp.) on YNP&rsquo;s northern range showed significant growth for the first time since the 1920s. However, the pace of willow recovery has not been uniform. Some communities have exceeded 400 cm, while others are still at pre-1995 levels of &#60;80 cm mean height. We took intensive, repeated measurements of abiotic factors, including soil and water-table characteristics, to determine whether these factors might be contributing to the varying pace of willow recovery. Willows at all of our study sites were &ldquo;short&rdquo; (&#60;250 cm max. height) prior to 1995 and have recovered to varying degrees since. We contrasted &ldquo;tall&rdquo; (>250 cm max. height) willow sites where willows had escaped elk ( Cervus elaphus L.) browsing with &ldquo;short&rdquo; willow sites that could still be browsed. Unlike studies that manipulated willow height with fences and artificial dams, we examined sites that had natural growth differences in height since the reintroduction of wolves. Tall willow sites had greater water availability, more-rapid net soil nitrogen mineralization, greater snow depth, lower soil respiration rates, and cooler summer soil temperatures than nearby short willow sites. Most of these differences were measured both in herbaceous areas adjacent to the willow patches and in the willow patches themselves, suggesting that they were not effects of varying willow height recovery but were instead preexisting site differences that may have contributed to increased plant productivity. Our results agree with earlier studies in experimental plots which suggest that the varying pace of willow recovery has been influenced by abiotic limiting factors that interact with top-down reductions in willow browsing by elk.     

Vegetation response to fire and postburn seeding treatments in juniper woodlands of the Grand Staircase-Escalante National Monument, Utah

We compared 3 naturally ignited burns with unburned sites in the Grand Staircase-Escalante National Monument. Each burn site was restored with native and nonnative seed mixes, restored with native seeds only, or regenerated naturally. In general, burned sites had significantly lower native species richness (1.8 vs. 2.9 species), native species cover (11% vs. 22.5%), and soil crust cover (4.1% vs. 15%) than unburned sites. Most burned plots, seeded or not, had significantly higher average nonnative species richness and cover and lower average native species richness and cover than unburned sites. Regression tree analyses suggest site variation was equally important to rehabilitation results as seeding treatments. Low native species richness and cover, high soil C, and low cover of biological soil crusts may facilitate increased nonnative species richness and cover. Our study also found that unburned sites in the region had equally high cover of nonnative species compared with the rest of the Monument. Cheatgrass ( Bromus tectorum ) dominated both burned and unburned sites. Despite the invasion of cheatgrass, unburned sites still maintain higher native species richness; however, the high cover of cheatgrass may increase fire frequency, further reduce native species richness and cover, and ultimately change vegetation composition in juniper woodlands.     

Habitat characteristics of small mammals in southeastern Utah

We describe habitat characteristics of 8 small mammal species occurring in the Manti-LaSal National Forest in southeastern Utah. Thirty-seven grids across 7 vegetation types were sample by live-trapping from May through October 1994 and 1995. Logistic regression models of habitat measurements correctly classified small mammal presence 36%-87% of the time. Except for 1 instance, 4 Peromyscus species present in a specific vegetation type were negatively associated with forb or grass cover. Microtus montanus was present primarily on mesas and was positively associated with tall tree and low shrub cover. Neotoma mexicana was present only in canyons and was found primarily in the pinyon-juniper ( Pinus edulis-Juniperus osteosperma ) vegetation type. Tamias spp. was present in all vegetation types. Our results allow better management of these species by providing greater understanding of their use of habitat within vegetation types.     

Livestock and vegetation responses to rotational grazing in short-grass steppe

There is a paucity of information concerning livestock and vegetation responses to rotational grazing in short-grass steppe. We compared effects between 1995 and 2003 of time-controlled, short-duration rotational grazing against season-long continuous grazing, at a moderate stocking rate (1.95 ha ? animal unit month –1 ), on livestock gains and on foliar and basal cover in short-grass steppe. Livestock average daily gains, grazing-season gains, and beef production did not differ between grazing systems. We observed no relationship between precipitation (annual or growing-season) and average daily gain. In contrast, both grazing-season gains and beef production exhibited a significant curvilinear response to both growing-season and annual precipitation. Basal and foliar cover of all plant functional groups (C 3 annual grasses, C 3 perennial grasses and grass-likes, C 4 perennial grasses, cactus, annual forbs, perennial forbs, and shrubs/subshrubs) did not differ between grazing systems. Litter and bare ground were also unaffected by grazing system, with litter increasing and bare ground decreasing over the duration of this experiment. Land managers in shortgrass steppe who are implementing rotational grazing at moderate stocking rates should not expect increased livestock gains or changes in basal and foliar cover of the plant community. Rotational grazing may be a useful management tool for achieving conservation goals through modifications of seasonality and intensity of use in paddocks within larger management units to accommodate spatial variability in vegetation and temporal variation in precipitation.     

Habitat use by small mammals in southeastern Utah, with reference to Mexican Spotted Owl management

We determined temporal and spatial differences in abundance and habitat use by small mammals in southeastern Utah as part of an effort to enhance management of the Mexican Spotted Owl ( Strix occidentalis lucida ), listed by the federal government as threatened. Woodrats ( Neotoma spp.) were captured only in canyons and most frequently in the pinyon-juniper ( Pinus edulis-Juniperus osteosperma ) vegetation type. White-footed mice ( Peromyscus spp.) were found in a variety of vegetation types in both canyons and mesas. The deer mouse ( P. maniculatus ) was generally the most frequently captured species among vegetation types. We found seasonal and yearly differences in relative abundance of each small mammal species. Our data suggest that the pinyon-juniper vegetation type within canyons is an important component of Mexican Spotted Owl habitat.     

Diet similarity between elk and deer in Utah

Growing numbers of elk ( Cervus elaphus ) on winter ranges might adversely affect sympatric wintering mule deer ( Odoeoileus hemionus ) if diets of the two species are similar. Diets of elk and deer on a northern Utah range were analyzed for overlap in winter with microhistological analysis of fecal samples. Diets overlapped 71%. No significant difference was found in use of grasses or shrubs between elk and deer; however, use of forbs was significantly different. Shrubs comprised the largest proportion of the diets of both elk and deer. Deer might be under more severe dietary stress than elk on poor winter ranges.