Ectomycorrhizal colonization and rooting characteristics were quantified in a mature ponderosa pine (Pinus ponderosa Dougl. ex Laws.) stand in the western Sierra Nevada. Root length totaled 3835.9 m · m^-2 of forest floor surface area, with 96% consisting of the fine-root fraction. Total root dry weight and volume were 2230.4 g · m^-2 and 5807.4 cm³ · m^-2 of forest floor area, respectively, with 69% of the former and 75% of the latter accounted for by the coarse fraction. Fine roots were most prevalent in the upper 15 cm of the mineral soil profile, and their abundance declined with increasing depth. Coarse roots were most abundant at a depth of 15–30 cm. Ectomycorrhizal counts totaled 26,814 · m^-2 of forest floor area, and an overwhelming preponderance was associated with the fine-root fraction More than three-quarters of mychorrhizae resided in the upper 15 cm of mineral soil, with an overall trend of declining numbers with increasing depth. Roots and mycorrhizae were exceedingly scarce at a depth of 45–60 cm, and neither was found in the organic soil layer above the mineral profile. A necessary step in understanding the ecophysiological role of mycorrhizae in mature forests is to quantify their abundance in such settings, and the results of this study contribute such information for ponderosa pine.

Examination of specimens of Pediomelum in the Brigham Young University Stanley L. Welsh Herbarium (BRY), and others obtained on loan from the Northern Arizona University Deaver Herbarium (ASC), the Arizona State University Herbarium (ASU), and the University of Arizona Herbarium (ARIZ), allows for substantial reevaluations of the species in Arizona and for description of 2 previously undescribed species. Pediomelum verdiensis S.L. Welsh and M. Licher is described as a new species from substrate derived from the Tertiary Verde Formation, Verde Valley, north central Arizona. Pediomelum pauperitense S.L. Welsh, M. Licher, and N.D. Atwood is described as a new species from outcrops of Paleozoic limestone near Poverty Mountain, Coconino County, Arizona, north of the Grand Canyon. For the species of Pediomelum in Arizona, we include a summary revision, a key to the taxa, and a list of specimens examined for study.

During winter 1996–1997 and summer 1997, we surveyed birds at 26 study sites in desert grasslands of Arizona and New Mexico to determine tolerance of birds to variability in plant composition and structure. The relationship between bird abundance and vegetative characteristics might be an important consideration in the development of management and restoration plans. Of the 49 bird species we observed, we examined 13 and 16 species in detail for winter and summer seasons, respectively. A noticeable shift in species composition occurred between 3% and 10% woody plant cover. During winter, Chestnut-collared Longspurs (Calcarius ornatus) and Horned Larks (Eremophila alpestris) showed significant positive relationships with grass cover and negative relationships with woody plant cover, occurring in greatest numbers where woody cover was < 1%. The richness of sparrow species during winter was highest among sites with 6% to 15% woody plant cover. In addition to showing significant positive relationships with woody cover, Vesper Sparrows (Pooecetes gramineus), Black-throated Sparrows (Amphispiza bilineata), Brewer's Sparrows (Spizella breweri), and Chipping Sparrows (S. passerina) showed significant positive relationships with shrub species richness. Our results showed that reductions of woody plant cover below 3% in combination with the presence of native grasses could substantially enhance the presence of several bird species. Maintenance of woody cover between 6% and 15% could increase use by a suite of other species, especially wintering sparrows.

The southern Oregon—northeastern California and extreme northwestern Nevada (hereafter “SONEC”) region provides critical spring migration habitat for waterfowl and other waterbirds in the Pacific Flyway. Information on the dynamics and distribution of waterbird habitats in SONEC during spring is needed to guide conservation efforts in the region. We grouped 1992 National Land Cover Data classes into 5 potential waterbird habitat types and used Landsat 5 Thematic Mapper and Landsat 7 Enhanced Thematic Mapper Plus satellite imagery to map flooding of these habitat types in SONEC during February–May, 2002 and 2003. SONEC included 13,727 km² of potential waterbird habitat comprised of grasslands (37.1%), pasture/hay (24.6%), marsh (15.9%), open wetland (11.8%), and croplands (10.6%). On average, 11.9% of this potential habitat was flooded during spring; but the percentage, area, and composition varied within and among years and subregions. Total flooding increased from 693 km² in February to 2099 km² in April during 2002 and from 1630 km² in February to 2125 km² in May during 2003. Open wetland comprised 58%–74%, marsh 8%–18%, pasture/hay 4%–11%, grassland 4%–17%, and cropland 3%–8% of the flooded habitat in SONEC. Satellite imagery and land-use data provided useful estimates of waterbird habitat availability in SONEC during spring, but other methods should be tested to more accurately measure flooding of densely vegetated habitats such as marsh. With < 12% of the potential habitat flooded on average during spring, conservation programs have ample opportunity to improve the SONEC landscape for migrating waterbirds.

Historical events have had a great impact on the biogeography of fishes of western North America. We examined the genetic variation of the speckled dace (Rhinichthys osculus) to determine the effects on this species of extensive hydrological changes during the last 10 million years in the Bonneville and Lahontan basins of the Great Basin and the upper Snake River Basin. Eight hundred sixty-nine base pairs of the mitochondrial gene cytochrome b were sequenced from 97 individuals representing 22 populations within these 3 basins, as well as from 2 individuals of longnose dace (Rhinichthys cataractae) that served as outgroups. Additionally, 13 speckled dace sequences representing 3 Bonneville populations were used from GenBank. Phylogenetic relationships were reconstructed using maximum parsimony and maximum likelihood criteria. Analysis of molecular variance was used to determine population structure and to estimate the amount of gene flow across the community boundaries. Three distinct clades were reconstructed representing the Lahontan Basin, the northern Bonneville and upper Snake River basins, and the southern Bonneville Basin. Additionally, most of the population structuring was explained by variation among basins (65.33%) Speckled dace demonstrated high genetic variation. As hypothesized, the northern and southern Bonneville specimens formed separate clades; however, the southern Bonneville clade was basal to a sister clade formed by the northern Bonneville/upper Snake River and Lahontan clades. These relationships indicate that Pliocene connections between the Snake, Lahontan, and Bonneville drainages, rather than more recent Pleistocene connections, best explain population structuring in speckled dace.

Understanding factors influencing the timing of den entrance and emergence of black bears (Ursus americanus) provides insight for bear management. We determined den entrance and emergence dates for bears in Rocky Mountain National Park (RMNP) and related these dates to vegetative productivity, weather, habitat, and demographic factors to assess the influence of these factors on denning chronology. Date of den entrance was most strongly influenced by age class, precipitation, and proportion of human-use areas in annual home ranges. Den entrance was typically later for adult bears during wetter years and when annual home ranges contained a greater proportion of human-use areas. Sex and presence of human-use areas were most strongly related to den emergence. Male bears typically emerged from dens before females, and bears emerged from dens earlier when human-use areas composed a greater proportion of annual home ranges. Collectively, our results suggest that denning behavior of black bears in RMNP was strongly influenced by presence of human-use areas, likely because of foods associated with such areas. Managers of black bears in RMNP can use precipitation to predict relative dates of den entrance, thereby allowing for more efficient strategies to combat potentially negative human—black bear encounters.

Natural establishment of seedlings in desert playas with temporally variable precipitation hinges on many factors, including seed production, seed dispersal, seed entrapment, seed germination, and seedling survival. We investigated natural seed dispersal patterns and the effects of surface texture, wind barriers, resource availability (water and nutrients), and protection from herbivory on seedling establishment in a desert playa. We hypothesized that the seed rain would be consistent throughout the year and that seedling establishment would improve in resource-amended plots with barriers to wind dispersal. Contrary to our hypotheses, seed flux peaked seasonally during the winter, and fertilization had no consistent effect on seedling establishment. Seed availability for dispersal correlated with precipitation in the previous water year, whereas seedling recruitment was greatest when current-year precipitation during the spring germination and summer seedling growth periods was high. Gravel and barrier surface treatments contained more surviving seedlings than other surface treatments. Comparison with plots located outside of herbivore exclosures, however, showed that greater seedling presence in gravel plots may be due somewhat to protection from herbivory provided by the gravel, rather than simply to the greater seed-trapping quality of the gravel. With abundant seed availability, application of surface treatments, like coarse gravel, combined with increased seasonal water availability could lead to improved shrub establishment from seed in desert playas.

The sagebrush biotype is the largest in the western United States. This vast sagebrush community is thought to harbor equally vast and diverse arthropod communities, but these remain little explored. Our objective was to examine the diversity, abundance, and seasonal phenology of arthropod taxa found on the dominant shrub of the sagebrush ecosystem, big sagebrush (Artemisia tridentata). We wanted to improve understanding of this little-studied arthropod assemblage that may play significant roles in the dynamics of sagebrush populations and the sagebrush ecosystem. We sampled free-living and gall-forming arthropods from a stratified random sample of sagebrush plants at the Barton Road Ecological Research Area, Idaho, resulting in a sample of over 8000 individuals and 232 morphospecies. Species richness and abundance declined from May to August, and abundance of most taxa similarly declined over the summer. A few taxa, including Acari (mites), were notably more abundant in August. Fluid feeders were the most diverse and abundant free-living feeding guild during all months and comprised up to 79% of morphospecies. The gall formers included 4713 individuals of 12 species of gall flies (Rhopalomyia spp.), primarily (97%) R. ampullaria. Abundance of galls increased from small to large (presumably young to old) plants. Overall, A. tridentata was host to a high diversity of arthropods, some of which have potential to cause or mitigate significant damage to their host plant. Arthropods seem likely to have the greatest impact on sagebrush early in the growing season, when they are most diverse and abundant. Documentation of the full diversity of arthropods associated with sagebrush required samples taken throughout the growing season, but a single sample early in the growing season captured a high proportion of taxa.

Redband trout Oncorhynchus mykiss gairdneri in the Columbia River Basin of western North America occupy desert and montane streams with variable habitat conditions. In general, desert streams are lower in gradient and elevation, contain less large substrate and more silt substrate, are less shaded by overhead vegetation, and have higher summer water temperature than montane streams. Consequently, we assessed whether the relationships between biotic and abiotic factors and the occurrence and abundance of redband trout in southwestern Idaho differed between desert and montane streams (<25 m mean width). Increased occurrence of redband trout in desert streams was most strongly related to increased stream shading and decreased amounts of silt substrate, followed by increased amounts of cobble/boulder substrate and absence of piscivorous fish (i.e., smallmouth bass Micropterus dolomieui and northern pikeminnow Ptychocheilus oregonensis). In montane streams, increased occurrence of redband trout was most strongly related to decreased site elevation and increases in cobble/boulder substrate, followed by decreases in stream gradient and width. Furthermore, occurrence of redband trout decreased in desert streams at mean summer (June–August) water temperature (Temp_smr) > 16 °C. whereas for montane streams, occurrence increased at Temp_smr >9 °C Redband trout density in desert streams was most strongly related to higher stream order (i.e., headwater streams), increased stream shading, and increased amounts of cobble/boulder substrate. In montane streams, redband trout density was not well explained by any stream conditions, but stream shading had the strongest positive relationship with density. Redband trout density was negatively related to Temp_smr in desert streams, but the relationship was weak for montane streams. That environmental conditions related to the occurrence and abundance of redband trout differ between desert and montane streams is important for fisheries managers who manage these disparate populations occurring in such close proximity to each other.

During the summers of 2005 and 2006, northern flying squirrels (Glaucomys sabrinus Shaw) were live-captured in the northern Black Hills of South Dakota from mixed deciduous/coniferous and coniferous habitats. Squirrel captures were significantly correlated with volume of downed wood and number of snags. Diets were examined from scat collections (n = 40, deciduous/coniferous; n = 10, coniferous). Number of fungal spores in the scat was significantly correlated with number of snags. From each scat collection, the frequencies of plant, animal, fungal, and unidentified components were determined. Hypogeous fungi were a frequent component of the diet, being found in 98.3% and 78.8% of the scat observed in 2005 and 2006. In 2006, as the frequency of dietary fungi decreased, the frequency of plant material increased from <1.0% to 8.0% and frequency of unidentified material increased from 2.0% to 74.0%. Animal content in the scat was negligible (<1.0% to 1.0%) Rhizopogon was the most frequently occurring hypogeous fungus observed. Rhizopogon spores made up 97.9% of the spores counted in 2005 and 96.4% in 2006. Elaphomyces, Gautieria, Geopora, Hymenogaster, and Hysterangium were observed at much lower frequencies. Sporocarps were collected throughout the trapping periods. Fourteen were collected in 2005 and 12 in 2006. Of the 26 sporocarps collected, 11 were Rhizopogon, 4 Elaphomyces, 2 Gautieria, 1 Hymenogaster, 7 Hysterangium, and 1 Tuber. This study is the first to examine flying squirrel diets in the Black Hills and the first to report Elaphomyces, Gautieria, Hymenogaster, Hysterangium, Rhizopogon, and Tuber sporocarps from the South Dakota Black Hills.

The Least Bell's Vireo (Vireo bellii pusillus) was listed as state endangered in 1980 and federally endangered in 1986 in response to a sharp population decline and range reduction. This vireo commonly bred in riparian forests throughout the Central Valley of California, but prior to 2005, no nesting pairs had been confirmed in the region in over 50 years. On 29 June 2005, a Least Bell's Vireo nest was located in a 3-year-old riparian restoration site at the San Joaquin River National Wildlife Refuge in Stanislaus County, California. In 2006, a Least Bell's Vireo pair returned to the refuge to successfully breed, followed by an unsuccessful attempt in 2007 by an unpaired female. These records are approximately 350 km from the nearest known breeding population and appear to be part of a growing number of sightings outside of the species' current southern California breeding range. These nesting attempts lend credence to the idea that extirpated species can recolonize restored habitat by long-distance dispersal.

A wide variety of blood-feeding Diptera feed on extrafloral sugar sources such as homopteran honeydew. The significance of these sugar sources to insect survival and disease transmission is poorly known. Culicoides sonorensis, a biting midge, can survive on plant sugars but might also feed on homopteran honeydew. The survival of C. sonorensis fed 10% melezitose or 10% stachyose was compared to that of C. sonorensis fed 10% sucrose. A significantly greater number of C. sonorensis survived longer when fed melezitose than when fed either stachyose or sucrose. The effect of sugar meals on vector competence was measured using bluetongue and epizootic hemorrhagic disease viruses. There was no significant difference in viral persistence. However, if C. sonorensis feeds on homopteran honeydew in the wild, a larger number of midges could survive to transmit orbiviruses.

We report 2 separate records from sport-fish anglers in Lake Mohave, Arizona—Nevada, that document the presence of endangered razorback sucker Xyrauchen texanus and bonytail Gila elegans in stomach contents of large (13 kg) nonnative striped bass Morone saxatilis. These records suggest that striped bass, since their first appearance in Lake Mohave nearly 3 decades ago, may have played a role in population declines of the other 2 species. Current native-fish stocking programs at Lake Mohave continue to face significant obstacles to achieving population recoveries because all life stages of repatriated individuals, including mature adults, are vulnerable to predation.

From April to July 2008, we surveyed for breeding plovers at 32 sites in the semiarid highlands of Jalisco, Aguascalientes, Zacatecas, and San Luis Potosí, in the Central Mexican High Plateau. We documented evidence or presumption of breeding Snowy Plovers (Charadrius alexandrinus) at 3 sites, Killdeer (C. vociferus) at 15 sites, and Mountain Plovers (C. montanus) at 1 site Our surveys showed that the region is important breeding ground for only the Killdeer. We documented an apparent breeding range extension of the Mountain Plover to slightly more than 200 km south of its previously known breeding range.

The hispid pocket mouse (Chaetodipus hispidus) occurs throughout the Great Plains, mainly west of the Missouri River. In Nebraska, this species likely occurs throughout the state, but records of occurrence were lacking for east-central and northeastern counties. During a survey in 2008 for the plains pocket mouse (Perognathus flavescens) in eastern Nebraska, we documented C. hispidus in 10 new counties, including a modest range expansion into northeastern Nebraska. Many individuals were captured on moderately compact soils consisting of silt, but some also were captured on sandy and other friable soils. Most individuals were captured in areas containing some exposed ground, but this may reflect our trap placement for P. flavescens. Individuals from northeastern and east-central Nebraska best resembled C. h. spilotus from southeastern Nebraska, with black coloration suffused on the dorsum, head, and dorsal side of the tail; however, our individuals generally lacked the characteristic bright ochraceous coloration along lateral lines and on the dorsum. Limited evidence supports a recent expansion in distribution within the region.