Autumn and winter food habits of bobcats in Washington state

The stomach contents were examined from 324 western Washington bobcats ( Felis rufus ) and 123 from eastern Washington taken by hunters from 1976 through 1980, for major prey items as well as sex- and age-related differences in diet. Western Washington bobcats ate primarily mountain beavers ( Aplodontia rufa ) (42% occurrence) and snowshoe hares ( Lepus americanus ) (26%). Within that population females ate larger quantities of smaller prey such as douglas squirrels ( Tamiasciurus douglasi ) and lesser amounts of deer ( Odocoileus sp.) than males. Bobcat diets in eastern Washington were more diverse; main foods consisted of lagomorphs ( Sylvilagus nuttallii, Lepus sp.) (20%), red squirrels ( Tamiasciurus hudsonicus ) (15%), deer (11%), and voles ( Microtus sp.) (11%). Age-related differences were most prevalent in this population, with adults consuming larger quantities of deer and larger prey than did kittens.     

Diets of sympatric bobcats and coyotes during years of varying rainfall in central Arizona

We collected fecal samples (scats) of sympatric bobcats ( Lynx rufus ) and coyotes ( Canis latrans ) between 2000 and 2003 in a 53,600-ha area of the Upper Sonoran Desert in central Arizona. Our objective was to investigate composition, diversity, and overlap of diets of bobcats and coyotes in relation to varying rainfall in the Sonoran Desert of central Arizona. In general, bobcats ate more rodents than did coyotes, and coyotes ate more lagomorphs, large prey, and fruit/seeds than did bobcats. Composition of bobcat diets was independent of differences among years in annual rainfall and seasonal rainfall during summer–autumn (May–October) and winter–spring (November–April). Composition of coyote diets also was independent of drought conditions among years during summer–autumn, but coyotes ate more large prey and fewer rodents during years with winter–spring drought. Seasonally, bobcats ate more rodents than did coyotes in summer–autumn and winter–spring, whereas coyotes ate more lagomorphs than did bobcats during winter– spring, and more large prey and fruit/seeds in both seasons. Coyotes ate more large prey and lagomorphs during winter–spring, when seasonal rainfall was higher, and more fruit/seeds in summer–autumn, when seasonal rainfall was lower. Diversity of diets was consistently higher for coyotes than for bobcats, and increased for bobcats but not for coyotes during winter–spring drought and during higher seasonal rainfall in winter–spring. Overlap of diets between predators was independent of rainfall levels. We suggest that bobcats in the Sonoran Desert are more selective, specialized predators and that coyotes are more generalist, opportunistic predators. We hypothesize that, although diversity of bobcat food items and composition of coyote diets differ with varying rainfall in the Sonoran Desert, patterns of feeding strategy are independent of seasonal differences in precipitation and effects of drought, and bobcats and coyotes partition food resources independently of varying rainfall.     

Avian use of desert wildlife water developments as determined by remote videography

In the desert Southwest, migrating birds have been documented using upland habitat and xeroriparian washes as well as riparian areas. Yet aside from the river corridors, natural water sources (e.g., natural rock tanks [tinajas], springs, and ephemeral washes) in upland areas are scarce. Because of this scarcity, state and federal resource managers augmented water sources throughout the Southwest by constructing permanent wildlife water developments with the intention of enhancing game populations. However, despite these increases in free-standing water, there is a paucity of information on the use of water by birds during migration. Our objectives were to document use of these wildlife water developments by resident and migratory songbirds and assess the effectiveness of monitoring these species using remote color videography. We placed color video cameras at 2 wildlife water developments in southwestern Arizona during the spring and fall of 2004. Although we observed more use by migrants during spring than fall, overall use by migratory birds was low. However, the wildlife water developments were frequently used by resident birds. Remote videography provided continuous information on daily and seasonal patterns of bird use at wildlife water catchments with negligible disturbance by observers, yet for passerines, we felt that the benefits of remote videography did not justify the high cost of equipment purchase, installation, maintenance, and data processing.     

Examining ecological consequences of feral horse grazing using exclosures

Although feral horses have inhabited western North America since the end of the 16th century, relatively little synecological research has been conducted to quantitatively characterize how they interact with ecosystem components. Because feral horses exhibit watering behavior markedly different from that of domestic cattle, it is particularly important to evaluate response of ecosystem elements near water sources to horse use. To assess this response, we performed live-trapping of small mammals and 2-tiered vegetative sampling in 2 mountain ranges in central Nevada in the interior Great Basin, USA. At low elevations, plots around horse-excluded springs exhibited notably greater plant species richness, percent cover, and abundance of grasses and shrubs, as well as more small mammal burrow entrances than plots at horse-grazed springs. At high elevations, meadows protected from grazing exhibited maximum vegetation heights 2.8 times greater than vegetation grazed by horses only and 4.5 times greater than vegetation grazed by horses and cattle. Species richness in quadrats was most different between the horse-and-cattle-grazed meadow and its ungrazed counterpart, suggesting the possibility of synergistic effects of horse and cattle grazing in the same location. This study, the first in the Great Basin to investigate quantitatively ecosystem consequences of feral horse use with exclosures, represents a preliminary step in identifying factors that determine the magnitude of horse grazing impacts.     

Organisms using Phragmites australis are diverse and similar on three continents

ABSTRACT

Common reed (Phragmites australis) is one of the most widely distributed, most abundant, and best-studied vascular plants worldwide but there has been no broad comparison of reed-associated biota on different continents. A survey of observational data on (mostly terrestrial) organisms using P. australis reedbeds revealed diverse biotas and some strong relationships to Phragmites in North America, Europe, and sub-Saharan Africa. I present examples for a selected group of 29 habitat functions (i.e., features of the reed plant or reedbed used in particular ways by groups of organisms). These functions include animals eating certain parts of reed, birds roosting in reedbeds, and insects mining within reed leaf blades. The diversity of reed users (associated species) and the similarities in habitat functions in biogeographically distinct world regions suggest a fundamental character of reed ecological relationships related to the large size, extensive stands, high productivity, deep litter layers, and other traits of reed. The data also underline the general importance of reed for biodiversity support, although on all three continents reed is considered desirable or undesirable depending on the site character and management goals. Managers can consider reed habitat functions and user guilds to prioritise and design management approaches and predict outcomes of conservation, management, or other environmental changes affecting reedbeds and their users, whether native or introduced, over-abundant or under-abundant.     

Efficacy of using passive integrated transponder technology to track individual shorthead sculpins

We evaluated the feasibility of using passive integrated transponder (PIT) tags to mark and track individual shorthead sculpins ( Cottus confusus ). We implanted PIT tags in 80 shorthead sculpins in 2 size categories (60–80 mm and 81–106 mm total length) and in 1 of 2 locations (subcutaneous along the spinous dorsal fin or in the body cavity). We evaluated tag retention, sculpin survival, and net-avoidance behavior for 29 days. We observed no mortality directly attributable to PIT-tag injection at either tagging location. We observed a 38.8% loss rate of dorsal tags and a 2.5% loss rate of body-cavity tags. No change in net-avoidance behavior was observed. We released 97 PIT-tagged sculpins into an artificial stream and monitored them with 3 stationary and 1 portable antenna. Sixty sculpins were detected at least once, and 18 sculpins were detected multiple times with the portable antenna. These results indicate that PIT-tagging within the body cavity is a feasible method for marking and tracking individual shorthead sculpins.     

Controlling performance of bluebunch wheatgrass and spotted knapweed using nitrogen and sucrose amendments

Range- and wildlands are being invaded by nonindigenous plants, resulting in an unprecedented, rapid change in plant community composition across the United States. Successional management predicts that species performance may be modified by resource availability. The objective of this study was to determine whether species performance could be altered by modifying soil nitrate (NO 3 – ) and ammonium (NH 4 + ) concentrations within an Idaho fescue ( Festuca idahoensis )/bluebunch wheatgrass ( Pseudoroegneria spicata ) plant association. We planted bluebunch wheatgrass and spotted knapweed ( Centaurea maculosa ) in an addition series at 2 sites in southwestern Montana. Each plot in the addition series matrix was divided into thirds, and we applied nitrogen (N) to a subplot and sucrose to a 2nd subplot. The remaining subplot was not amended and considered a control. Nitrogen amendment tended to enhance the performance of spotted knapweed, while sucrose amendment had no effect. Bluebunch wheatgrass performance was not affected by either amendment. Sucrose treatments only decreased soil NO 3 – at the more productive site. Regression models for predicting bluebunch wheatgrass and spotted knapweed biomass accounted for only about 30% of the variation, suggesting other processes in addition to interference were responsible for explaining relative plant perfor - mance. We recommend that land managers prevent activities that increase soil N concentration while the effectiveness of carbon amendments as a means to decrease soil N concentrations and shift interference relationships is further investigated.     

Growth of juvenile American lobsters in semiopen and closed culture systems using formulated diets

Growth of juvenile American lobsters, Homarus americanus , raised in four semiopen culture systems, with daily water exchange rates ranging from 29 percent to 3.3 percent, was compared with growth in a completely closed system. Animals were fed a formulated pelleted ration, water quality factors were measured daily, and changes in concentration of nitrate, orthophosphate, and total organic carbon were monitored. Results of two 90-day trials indicate that growth increased in the system with the lower water exchange rates. Maximum growth occurred in the closed system.     

Holocene vegetation and historic grazing impacts at Capitol Reef National Park reconstructed using packrat middens

Mid- to late-Holocene vegetation change from a remote high-desert site was reconstructed using plant macrofossils and pollen from 9 packrat middens ranging from 0 to 5400 yr in age. Presettlement middens consistently contained abundant macrofossils of plant species palatable to large herbivores that are now absent or reduced, such as winterfat ( Ceratoides lanata ) and ricegrass ( Stipa hymenoides ). Macrofossils and pollen of pinyon pine ( Pinus edulis ), sagebrush ( Artemisia spp.), and roundleaf buffaloberry ( Shepherdia rotundifolia ) were recently reduced to their lowest levels for the 5400-yr record. Conversely, species typical of overgrazed range, such as snakeweed ( Gutierrezia sarothrae ), viscid rabbitbrush ( Chrysothamnus visidiflorus ), and Russian thistle ( Salsola sp.), were not recorded prior to the historic introduction of grazing animals. Pollens of Utah juniper ( Juniperus osteosperma ) also increased during the last 200 yr. These records demonstrate that the most sever vegetation changes of the last 5400 yr occurred during the past 200 yr. The nature and timing of these changes suggest that they were primarily caused by the 19th-century open-land sheep and cattle ranching. The reduction of pinyon and sagebrush concurrent with other grazing impacts suggests that effects of cattle grazing at modern stocking levels may be a poor analog for the effects of intense sheep grazing during drought.     

Improving seed germination of Salicornia rubra (Chenopodiaceae) under saline conditions using germination-regulating chemicals

Salicornia rubra Nels. (Chenopodiaceae) is a salt-tolerant annual species occurring in salt playas of the Great Basin desert in western United States. It forms pioneer communities on the most saline location of an inland salt playa at Goshen, Utah. Seeds of Salicornia rubra are capable of germinating at 1000 mM NaCl at 25-35° C alternating temperature regime. Dormancy-regulating chemicals were evaluated for their ability to alleviate the innate and salinityenforced dormancy in seeds of Salicornia rubra . Betaine, GA3, kinetin, fusicoccin, ethephon, thiourea, proline, and nitrate had no effect in alleviating primary dormancy. Increases in NaCl concentration progressively inhibited germination of Salicornia rubra seeds. Ethephon, fusicoccin, GA3, kinetin, thiourea, and nitrate promoted germination under low saline conditions. At high salinity fusicoccin had no effect, whereas GA3, kinetin, and ethephon substantially alleviated salinity effects. Application of these dormancy-regulating compounds could be of practical value in seeding a saline area for restoration purposes, particularly under high saline conditions.     

Evaluating the relationship between mule deer pellet-group data and available winter range, using LANDSAT imagery

In this study, mule deer population trend data (deer-days-use/hectare) were statistically analyzed with range area data that were extracted from LANDSAT satellite imagery. The remote sensing techniques developed use multidate, winter images of an area in central Utah. Snow-covered areas and vegetational areas mapped from the imagery were composited into 26 maps representing the approximate winter range available to mule deer on 26 dates over a five-year period (1972–1977). Utah State Division of Wildlife Resources pellet-group transect data were statistically analyzed with range data measured from the satellite imagery. Range area accounted for a fairly large proportion of the variation in deer-days-use/hectare (r = –.83). This result seems reasonable since deer population density should increase as available range decreases.     

Estimating root biomass and distribution after fire in a Great Basin woodland using cores and pits

Quantifying root biomass is critical to an estimation and understanding of ecosystem net primary production, biomass partitioning, and belowground competition. We compared 2 methods for determining root biomass: a new soil-coring technique and traditional excavation of quantitative pits. We conducted the study in an existing Joint Fire Sciences demonstration area in the central Great Basin. This area is representative of a shrub (sagebrush) ecosystem exhibiting tree (pinyon and juniper) encroachment. The demonstration area had a prescribed burn implemented 4 years prior to our study, and we sampled both control and burned plots. The samples were stratified across 3 microsites (interspace, under shrub, and under tree) and 4 soil depths (0–8, 8–23, 23–38, and 38–52 cm) to determine the effects of plant life form and burning on root biomass. We found that estimates of total root biomass were similar between quantitative pits and our soil cores. However, cores tended to show a more even distribution of root biomass across all microsites and depths than did pits. Overall, results indicated that root biomass differs significantly among microsites and soil depths and that the amount of root biomass at a given depth differs among microsites. Burning reduced root biomass in our study by 23% and altered the spatial distribution of root mass.     

Warm water aquaculture using waste heat and water from zero discharge power plants in the Great Basin

Two series of experiments were completed to determine (a) toxicity of waste water from power plants on warm water fish and (b) multiple use of waste heat and water for aquatic animal and plant production. All three types of waste water from a typical coal-fired power plant are acceptable for growing catfish and tilapia following aeration. This growth was compared with fish raised in spring water. Closed, recirculating polyculture systems using evaporation pond water operated efficiently for plant (duckweed) and animal (fish and freshwater prawns) production. Duckweed is an excellent supplement for fish feed. Tilapia and freshwater prawns grew rapidly in the tanks containing duckweed only.        

Assessing cheatgrass ( Bromus tectorum ) genetic diversity and population structure using RAPD and microsatellite molecular markers

Two molecular marker systems, random amplified polymorphic DNA (RAPD) and microsatellites, were used to evaluate population diversity and differentiation in 4 northern Nevada Bromus tectorum populations. From 80 RAPD primers, we found 16 (20%) that yielded 165 strong repeatable bands. Of those bands, 60 (35.8%) were polymorphic. Of those, 21 met data-pruning guidelines for final analysis. RAPD variation was moderate (0.363, SE = 0.022), ranging from 0.312 to 0.404. Microsatellite variation was similar (0.234, SE = 0.051) but varied more widely, ranging from 0.009 to 0.551. All populations were out of Hardy-Weinberg equilibrium, as expected in a predominantly selfing species. RAPDs revealed significant differentiation (P Bromus rubens ).     

A Potamophylax larva (Trichoptera: Limnephilidae) using other caddisfly cases to construct its own case

Larvae of a species of Potamophylax (Trichoptera: Limnephilidae) from the Peñalara Natural Park (Madrid, Spain) constructed cases using the smaller cases of Sericostomatidae. Possible explanations for this behaviour are discussed.     

Population structure and paternity in an American black bear ( Ursus americanus ) population using microsatellite DNA

We report genetic microsatellite data from analysis of 71 American black bears ( Ursus americanus ) from the East Tavaputs Plateau in eastern Utah. Heterozygosity was 52.9%, which is lower than other mainland North American populations and possibly reflects low recruitment into the study area. We used a combination of known pedigrees (mother/cubs), relatedness estimates, and paternity estimation using CERVUS to infer single and possible multiple paternity within litters, breeding by pairs over consecutive years, and the possibility of a single male successfully breeding with multiple females in a single year. Estimates of inbreeding effective population size indicate the East Tavaputs Plateau population is part of a larger black bear population.     

Genetic differentiation of rare and common varieties of Eriogonum shockleyi (Polygonaceae) in Idaho using ISSR variability

Idaho populations of Eriogonum shockleyi are divided taxonomically into 2 varieties: E. shockleyi var. packardae , which is endemic to Idaho, and the typical variety, which is widespread in the western United States. Recent morphological investigations of E. shockleyi in Idaho have identified potentially reliable morphological characters for field identification of the subspecific taxa. This paper investigates the genetic basis for the separation of the 2 varieties of E. shockleyi using inter simple-sequence repeats (ISSR) markers. Although we found some morphological differences between the populations that correlated with the 2 varieties, we identified no molecular markers in this study to distinguish between them. Morphological measurements obtained in the field indicate that although a population may have an overall average morphology that defines the variety, some individuals in nearly all populations have putative diagnostic characters that define the other variety. The morphological characters used to distinguish the 2 varieties are most likely the result of environmental variability and could result from differences in precipitation and soil water retention. Alternatively, high levels of outcrossing through pollen flow could be obscuring selection for morphological characters at particular sites.     

RCLUS, a new program for clustering associated species: a demonstration using a Mojave Desert plant community dataset

This paper presents a new clustering program named RCLUS that was developed for species (R-mode) analysis of plant community data. RCLUS identifies clusters of co-occurring species that meet a user-specified cutoff level of positive association with each other. The "strict affinity" clustering algorithm in RCLUS builds clusters of species whose pairwise associations all exceed the cutoff level, whereas the "coalition" clustering algorithm only requires that the mean pairwise association of the cluster exceeds the cutoff level. Both algorithms allow species to belong to multiple clusters, thus accommodating both generalist and specialist species. Using a 60-plot dataset of perennial plants occurring on the Beaver Dam Slope in southwestern Utah, we carried out RCLUS analyses and compared the results with 2 widely used clustering techniques: UPGMA and PAM. We found that many of the RCLUS clusters were subsets of the UPGMA and PAM clusters, although novel species combinations were also generated by RCLUS. An advantage of RCLUS over these methods is its ability to exclude species that are poorly represented in a dataset as well as species lacking strong association patterns. The RCLUS program also includes modules that assess the affinity of a given species, plot, or environmental variable to a given cluster. We found statistically significant correlations between some of the RCLUS species clusters and certain environmental variables of the study area (elevation and topographical position). We also noted differences in clustering behavior when different association coefficients were used in RCLUS and found that those incorporating joint absences (e.g., the phi coefficient) produced more clusters and more even numbers of species per cluster than those not incorporating joint absences (e.g., the Jaccard index). In addition to the species association application described in this paper, the RCLUS algorithms could be used for preliminary data stratification in sample (Q-mode) analysis. The indirect link between sample plots and RCLUS species clusters could also be exploited to yield a form of "fuzzy" classification of plots or to characterize species pools of plots.     

Taxonomic revision of Amerus troisi (Berlese, 1883) (Acari,Oribatida, Ameridae) using morphological and biochemical characters

This paper redescribes the classical taxon Amerus troisi (Berlese, 1883) on the basis of topotypical material. A new species, Amerus cuspidatus, characterized by short interlamellar setae and a distinct rostral morphology, is also described. In spite of overlapping biogeographical distributions, biochemical analysis indicates that the two Amerus species are clearly differentiated.