Influence of experimental habitat manipulations on a desert rodent population in southern Utah

This paper addresses how habitat manipulations in a black sagebrush ( Artemisia nova ) -dominated area, John's Valley of southern Utah, affected resident desert rodent populations. Rodents studied included the deer mouse ( Peromyscus maniculatus ), Great Basin pocket mouse ( Perognathus parvus ), sagebrush vole ( Lagurus curtatus ), Ord's kangaroo rat ( Dipodomys ordii ), and least chipmunk ( Eutamias minimus ). The experimental design involved analyses of treatment and control (nontreatment) plots rather than pre- and posttreatment of all plots. Habitat manipulations emphasized cutting of shrubs (rotobeating), treatment of plants with a herbicide (2,4-D), and reseeding with a mixture of grasses, forbs, and shrubs. Posttreatment trapping indicated the deer mouse was the most abundant rodent in treatment and control plots. Data indicate the prescribed habitat treatments had no significant negative affects on the deer mouse demes on the control or treatment plots. Habitat treatments may have negatively impacted recruitment in pocket mice. Least chipmunks were not captured in plots treated by rotobeating. Our habitat manipulations may have contributed to interspecific competition in this rodent community through the reduction of both food and cover.     

Vegetative and edaphic factors affecting abundance and distribution of small mammals in southeast Oregon

The relationships between vegetative and edaphic habitat factors and the local distribution and abundance of small mammals on Malheur National Wildlife Refuge, Harney County, Oregon, were examined between July 1973 and June 1975. Of 16 species of small mammals captured, deer mice ( Peromyscus maniculatus ), montane voles ( Microtus montanus ), Great Basin pocket mice ( Perognathus parvus ), and least chipmunks ( Eutamias minimus ) comprised 90.1 percent of the individuals. The physiognomy of the vegetation was a factor in the distribution of rodent species other than deer mice. Pocket mice and chipmunks were restricted to the communities dominated by sagebrush ( Artemisia tridentata ) or greasewood ( Sarcobatus vermiculatus ). Population densities of pocket mice and chipmunks were significantly related to edaphic factors such as soil depth, texture, and strength, which may have affected the construction and stability of burrows. Montane voles occurred only in marsh or grassland communities. Population densities of voles were directly correlated with the amount of cover and inversely correlated with its patchiness. Deer mice were the most common species encountered and occurred in all but the grassland communities. The density of this species was related to vegetative or edaphic factors only seasonally or in certain habitats, and few generalizations could be made.     

Habitat and diet of Bhutan takin Budorcas taxicolor whitei during summer in Jigme Dorji National Park,Bhutan

Little is known about the ecology of the rare and vulnerable Bhutan takin Budorcas taxicolor whitei, a large and basically forest-dwelling goat-antelope inhabiting mountain valleys in northern Bhutan. In Tsharijathang valley (3800 m asl) in Jigme Dorji National Park, we described the summer habitat of this takin subspecies through vegetation transects and by studying diet via microhistological analysis of faeces supplemented by examination of feeding sites. The habitats utilized by the c.250 animals occupying the valley consisted of six main vegetation types with roughly equal coverages, viz. three forest types (dominated by Juniperus, Betula or Abies), alpine scrub (mainly low Rhododendron shrubs), open alpine meadow (mainly graminoids and forbs) and semi-open willow shrub (mainly Salix and forbs). Sixty-eight food species were identified in the feeding sites, but the bulk of the diet consisted of ≈10 species, the same species that also dominated the faecal material. With >50% of the diet consisting of shrubs, mainly Salix myrtillacea, the takins were mainly browsers. When foraging, they exhibited a weak form of selection by choosing sites with a slightly higher coverage of the most important food species and, while at these, proportionally more feeding signs were recorded. Domestic yak Bos grunniens are allowed to graze in the study area during winter when the takins have descended to lower elevation. At the present grazing pressure, the wintering yaks probably benefit the takin by maintaining the open vegetation structure, but their numbers and impact on the habitat should be monitored to prevent adverse effects.     

Botanical content of black-tailed jackrabbit diets on semidesert rangeland

Botanical content of black-tailed jackrabbit diets was determined by microhistological examination of fecal samples collected from six different vegetation types in southern New Mexico on three dates. Grasses comprised the largest component of the jackrabbit diets, with dropseed species ( Sporobolus spp.) and black grama ( Bouteloua eriopoda ) the most abundant grasses in the diets. Leatherweed croton ( Croton pottsii ) and silverleaf nightshade ( Solanum elaeagnifolium ) were important forbs on most vegetation types. Diet composition varied in response to season and vegetation type. Grasses were important during the summer growing season, while forbs were selected during their growing season (summer or winter-spring). Shrubs were less abundant in the diet than grasses and forbs.     

Habitat affinities of rodents in northeastern Nevada rangeland communities

From May 1978 through September 1980, baseline data for rodent populations were collected by livetrapping in the Saval Ranch area of northeastern Nevada. The objectives of this study were to determine species composition and relative abundance of rodents for the various range sites. The 3 most abundant and uniformly distributed species were deer mice ( Peromyscus maniculatus ), Great Basin pocket mice ( Perognathus parvus ), and least chipmunks ( Neotamias minimus ). Relative abundance indices and densities reported for most species were similar to those reported in other multiyear studies at similar sites. The composition and relative abundance / density of rodent species was variable among habitats and over time. Diverse rodent species within the sagebrush ecosystem have commensurately diverse habitat requirements that should be considered when vegetation management is planned. Annual population fluctuations and differences among similar habitats should be considered when researchers propose to test rodent population responses to livestock grazing or other habitat treatments.     

Summer food habits of coyotes in central Wyoming

Summer food habits of coyotes ( Canis latrans ) were investigated on a 3100-km 2 area in central Wyoming, divided into one deer-use area and five non-deer areas. Analysis of 404 scats (fecal samples) revealed an overall average of 63 percent occurrence of native ungulates, 63 percent leporids, 46 percent rodents, 14 percent livestock, and 11 percent birds. Pronghorn ( Antilocapra Americana ) was the ungulate most frequently consumed, occurring in about 87 percent of the scats. Mule deer ( Odocoileus hemionus ) occurred in only 8 percent, and in 5 percent the native ungulate remains were not identifiable beyond order. This large percentage of big game in the diet is apparently unusual, because big game has been of minor importance in most coyote food-habit studies. The high incidence of leporids is consistent with other studies performed in arid intermountain areas. Although cricetines, especially deer mice ( Peromyscus maniculatus ), were trapped consistently in all habitats, months, and trapping areas, they were found in scats at a lower frequency than microtines and sciurids. This suggests a coyote hunting strategy that selected for the latter two groups.     

Diets of sympatric red foxes and coyotes in southeastern Idaho

Scats of sympatric red foxes and coyotes from the upper Snake River Plain of southeastern Idaho were analyzed for composition. Rodent remains in general and those of cricetid mice in particular occurred more frequently in scats of red foxes during all seasons of the year than any other food items identified. Scats of coyotes differed significantly in content from scats of red foxes during winter and contained primarily pygmy rabbit remains. In summer, remains of pygmy rabbits, sheep, ground squirrels, yellow-bellied marmots, arthropods, and vegetation were formed more frequently in scats of coyotes and remains of cricetid mice occurred more frequently in scats of red foxes. Red foxes and coyotes generally consumed similar food items but in different proportions. Based on the location of scats that were collected, red foxes and coyotes largely used different portions of the study area. Reasons for the preferential usage of habitat are discussed.     

Plant community patterns in unburned and burned blackbrush ( Coleogne ramosissima Torr.) shrublands in the Mojave Desert

The blackbrush vegetation type is dominated by Coleogyne ramossisima , which is thought to preclude the coexistence of many other plant species. Fire can remove blackbrush cover and possibly increase plant species richness and evenness. Fire also may increase the frequency and cover of alien annual grasses, thereby intensifying landscape flammability. We tested these predictions in unburned and burned (6-14 years postfire) blackbrush at 3 sites spanning the range of this vegetation type in the Mojave Desert. Species richness in unburned blackbrush was similar to published values for vegetation types in western North America, bur richness varied significantly among the 3 sites and 4 spatial scales (1, 10, 100, and 1000 m 2 ). Richness values declined in order from annual forbs, woody perennials, herbaceous perennials, annual grasses, cacti, to perennial grasses. Fire reduced Coleogyne cover, thus boosting species evenness. In contrast, species richness decreased after burning, although the results varied among spatial scales. Total cover was unaffected by fire because cover of wood perennials decreased, while cover of annual forbs, annual grasses, herbaceous perennials, and perennial grasses increased. Native species richness and cover decreased, whereas alien richness and cover increased after burning especially where the alien forb Erodium cicutarium was present. Fire had no effect on frequency and variable effects on cover of alien annual grasses. These results indicate that in blackbrush species richness can vary among sites and local spatial scales, and effects of fires can vary among plant life-forms and between natives and aliens.     

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.     

Habitat use and diet of the endemic lizard Ameivula nigrigula (Squamata: Teiidae) in Caatinga domain,Northeastern Brazil

ABSTRACT

The lizard Ameivula nigrigula is endemic to Caatinga vegetation and the transition zone between the Caatinga and Cerrado domains in Brazil. It was recently described, but little is known about its biology. We analysed microhabitat use and the diet of this species in Caatinga vegetation in Santo Inácio, Bahia State. Its diet consisted mainly of arthropods and plant material, and in particular aggregate (e.g. termites) and large preys (e.g. Coleoptera, insect larvae and spiders), reflecting their nutritional and energy values and high water contents. With regard to habitat use, we found A. nigrigula using microhabitats with tall vegetation over accumulated leaf litter, which could potentially contribute to temperature regulation. Together, those characteristics contribute to the survival of lizards in environments with low water availability and high temperatures, such as the Caatinga domain.     

Marmot scats supplement hay pile vegetation as food energy for pikas

During summer pikas do not store fat for the winter months; hay piles are the main energy source in winter. All the hay piles collected in an area where pikas ( Ochotona princeps ) coexisted with marmots ( Marmota flaviventris ) contained marmot scats. Marmot scats had a higher energy density than the most abundant type of vegetation in hay piles. In feeding trials pikas on a diet of hay pile vegetation plus marmot scats consumed significantly less food per day than they did on a diet of hay pile vegetation alone. These findings suggest that pikas coexisting with marmots use marmot scats to supplement the energy contained in the vegetational component of hay piles.     

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.     

Cheek pouch capacities and loading rates of deer mice ( Peromyscus maniculatus )

Eight deer mice ( Peromyscus maniculatus were attracted to bait stations in the field and filled their cheek pouches with seeds. Pouch capacity of the deer mice, which have small, internal cheek pouches, was 0.45 ± 0.11 mL, about 12-27% of that carried by similar-sized heteromyid rodents. Cheek pouches of deer mice, although small, give them the capacity to carry 3-5 times more food than unspecialized mice. This presumably increases efficiency of deer mice in exploiting small, particulate food items that are patchily distributed.     

Deer mouse ( Peromyscus maniculatus ) home-range size and fidelity in sage-steppe habitat

Within a species, home-range size can vary due to factors such as sex, mass, age, and breeding condition of individuals as well as habitat type, food availability, population density, and season. The objectives of this study were to estimate home ranges of deer mice ( Peromyscus maniculatus ) in sage-steppe habitat and to test the hypothesis that several factors (sex, mass, reproductive status, and seasonality) affect home-range size. We also tested the hypothesis that deer mice exhibit home-range fidelity over time. Passive integrated transponder (PIT) technology was used to estimate home ranges in June and September 2006. Home-range estimates varied from 360 m 2 to 5868 m 2 (65 individuals, 753 observations). Home-range size increased by approximately 60% from June to September. Besides seasonality, none of the other predictors of home range were informative in explaining the variation in home range. Deer mice recaptured in September (3 months after initial capture) had high fidelity in home-range use (42.1% [SE = 8.4%] overlap with 74.1% [SE = 8.7%] area conserved; n = 9). All animals for which home range was estimated in both seasons retained some fraction of their June home range in September. Results support the use of combined location data collected over long periods, such as weeks or months, to estimate home range for deer mice. The results have implications for deer mouse–pathogen ecology, particularly with respect to modeling transmission of Sin Nombre virus—a pathogen that is directly transmitted by deer mice.     

Summer food habits of coyotes in Idaho's River of No Return Wilderness Area

Summer food habits of coyotes ( Canis latrans )in the River of No Return Wilderness Area, Idaho, were determined. Analysis of 51 scats (fecal samples) revealed that Columbian ground squirrels ( Spermophilus columbianus ), mule deer ( Odocoileus hemionus ), and deer mice ( Peromyscus manniculatus ) exhibited the greatest frequency of occurrence for identified food items, being detected in 57%, 27%, and 16%, respectively, of scats examined.     

Gray Partridge foraging ecology in eastern South Dakota

We examined crop contents of 217 Gray Partridge ( Perdix perdix ) collected during a two-year period in eastern South Dakota. Row crop grains (corn, sunflowers) dominated late fall, winter, and spring diets. Small grains (oats, barley, wheat, rye) were rarely consumed although fields of small grains were widely available. During a severe winter when waste row crop grains were buried by snow, partridge consumed more leafy vegetation. Insects dominated the early summer diet, while foxtail ( Setaria spp.) seeds were a major late summer and early fall food.     

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.     

Comparison between plant species in bushy-tailed woodrat middens and in the habitat

Bushy-tailed woodrats ( Neotoma cinera ) collect vegetation and store it in middens. We asked to what extent plant species collected by woodrats reflect the array of species growing in the habitat. Species composition of plant clippings at 20 bushy-tailed woodrat middens in central Colorado were compared to vegetation growing within 30 m of the dens. Amount of overlap between midden and habitat species was low (28-49%) when all taxa were included; however, if only woody taxa were considered, overlap was 71-89%. Sorensen's Index of Similarity exhibited a like pattern; the index increased markedly if only woody taxa were included. Only one plant species not found within 30 m of a den occurred in significant amounts of the middens. Bushy-tailed woodrats collected a wide array of species but were more selective the greater the habitat plant diversity. Results of this and other studies indicate the concordance between midden contents and habitat vegetation decreases with increasing habitat plant diversity. Ancient woodrat middens are nonetheless useful to paleontologists seeking to reconstruct past vegetation associations in woody vegetation is well represented in middens.     

Scatter-hoarding behavior of deer mice ( Peromyscus maniculatus )

Deer mice ( Peromyscus maniculatus ) are known to larder hoard food, but their scatter-hoarding behavior is poorly documented. Eleven deer mice were each presented with 150 Jeffrey pine ( Pinus jeffreyi ) seeds in 10 γ 10- m enclosures in Jeffrey pine forests on the east slope of the Sierra Nevada. Subjects made a mean ± 1 s of 31.2 ± 30.0 caches per trial. Caches were shallow (most 2-12 mm deep) and usually contained only 1 or 2 seeds. Most caches were made at the edge of antelope bitterbrush ( Purshia tridentata ) shrubs in mineral soil or in thin layers of plant litter. These results suggest that deer mice might make a significant contribution to the dispersal of Jeffrey pine.     

Habitat use and food selection of small mammals near a sagebrush/crested wheatgrass interface in southeastern Idaho

Habitat use and food selection data were collected for deer mice ( Peromyscus maniculatus ), montane voles ( Microtus montanus ), Ord's kangaroo rats ( Dipodomys ordii ), and Townsend's ground squirrels ( Spermophilus townsendii ) near a sagebrush ( Artemisia tridentata )/crested wheatgrass ( Agropyron cristatum ) interface in southeastem Idaho. Significantly more captures occurred in the native sagebrush habitat than in areas planted in crested wheatgrass or in disturbed sites. Crested wheatgrass, a prolific seed producer, still accounted for over 30% of the total captures. Montane voles and Townsend's ground squirrels (during periods of aboveground activity) used the crested wheatgrass habitat throughout the summer, while deer mice and, Ord's kangaroo rats exhibited heavy use after seed set.