Beetles from the environs of Lake Powell in southern Utah and northern Arizona

Sixty-eight species of beetles of 14 families were collected in pit traps in 12 major vegetative communities during environmental monitoring studies in the summers of 1971 to 1973 in southern Utah and northern Arizona. Seasonal and plant community differences and correlations in population and composition were noted for the 16 sites studied. Highest populations and the most species were found in a grass community, but occurred in different months in each of the three years. Lowest populations were found in a Coleogyne community, and fewest species in an Artemisia- grass community.     

Ants of Utah

A man bitten on the finger by a wolf spider, Lycosa sp., experienced temporary bleeding and tingling of the finger, but no other symptoms occurred.     

Late Quaternary arthropods from the Colorado Plateau, Arizona and Utah

Late Quaternary-age arthropods were recovered from dry cave deposits and packrat middens located in the Grand Canyon, Canyonlands, and Glen Canyon region of the Colorado Plateau. This Quaternary data resource has not been analyzed before from the Colorado Plateau national parks. Radiocarbon dates on the various deposits containing arthropods range from 1510 to 30,660 yr B.P. The fossil assemblages yielded 57 identified taxa of insects, arachnids, and millipedes, including 15 taxa taken to the species level. The information from the fossil insect record of the Colorado Plateau is not yet sufficiently detailed to permit precise paleoenvironmental reconstructions. However, preliminary conclusions suggest a cooler, moister climatic regime during the late Wisconsin glacial and a mosaic of vegetation types, such as grassland and shrubby communities, unlike the present vegetation at the localities.     

Parasites from two species of suckers (Catostomidae) from southern Utah

Twenty Catostomus latipinnis and 50 Catostomus discobolis from La Verkin Creek and the Fremont River in southern Utah were collected and surveyed for parasites. Data from the survey indicated that 83 percent of the fish were infected with at least one parasite, with the fish from La Verkin Creek harboring more parasites. Twelve genera and 12 species of parasites were identified from these fish. A monogenetic trematode, Gyrodactylus elegans, which was found in 90 percent of the fish, was the most common parasite. Comments are included on habitat and host variations for the parasitofauna from suckers taken from the two locations.     

Range extension of Helianthus spp. (Asteraceae) in Arizona and Utah

Two populations of Helianthus niveus (Benth.) Brandegee ssp. canescens (A. Gray) Heiser were discovered in northern Arizona extending the range 300 miles north for this species. Helianthus deserticola Heiser range was extended 100 miles east in both Arizona and Utah.     

Phytogeography and floristics of pinyon-juniper woodlands in northern Arizona

This study assesses the floristic diversity and affinities of pinyon-juniper (PJ) woodlands in northern Arizona at 2 different scales: regionally within the context of North American floristic patterns and locally within the 2500-m elevation gradient of the San Francisco Volcanic Field (SFVF). An analysis based upon 245 North American floras indicates that the PJ woodlands of the SFVF share strong affinities with the adjacent Colorado Plateau and Apachian floristic elements but also show high floristic similarity to the Great Plains. Data suggest that mid-elevation woodlands of the Colorado Plateau share floristic affinities with the Great Plains that are as strong as or stronger than those shared with the Great Basin. A geostatisical analysis provides a spatially explicit depiction of these findings. A comparison of species occurrences between 6 adjacent biotic communities in northern Arizona reveals that the PJ woodlands host the most distinctive flora among local life zones. Despite what their simple woodland structure may suggest, PJ woodlands of the SFVF host a moderately species-rich flora. This study suggests that the floras of PJ woodlands vary in significant and important ways across the range of PJ woodlands in western North America.     

Fire history of Paunsaugunt Plateau in southern Utah

A fire history of the Pausaugunt Plateau in southern Utah was developed using dendrochronological methods. Fire frequencies of individual ponderosa pine trees from three sites on the plateau varied from 19.5 to 47 years. Composite fire intervals for the three sites ranged from 15.2 to 18.4 years. The last recorded fires in these study areas occurred in 1892, 1902, and 1911, corresponding to the initiation of fire suppression policies in the West. The absence of fire since 1911 may be contributing to a recently documented decrease in ponderosa pine regeneration within the high-elevation, mixed-coniferous forests of the Paunsaugunt Plateau.     

Compositional similarity within the oakbrush type in central and northern Utah

Indices of similarity were used to evaluate the similarity of oakbrush stands throughout the Uinta National Forest and to compare oak communities in central and northern Utah. Results show that Gambel oak stands in central Utah differ significantly among themselves in respect to quantitative aspects of the vegetation. Those differences can be correlated with elevation, slope exposure, and fire history. Nevertheless, there is currently inadequate justification for recognizing more than one habitat type for the species in the study area. There is a need to develop a model capable of predicting growth rate of oak on specific sites.     

Biogeographic significance of low-elevation records for Neotoma cinerea from the northern Bonneville Basin, Utah

The existence of low-elevation populations of Neotoma cinera in the northern Bonneville Basin shows either that these mammals can survive thousands of years in xeric habitats or that they can move across xeric lowlands far more readily than has been appreciated, or both. Current models of Great Basin small mammal biogeography are far too static to encompass properly the interaction of the wide range of geographical and biological variability that has produced the modern distribution of those mammals that have, for several decades, been treated as ""montane"" within the Great Basin.     

Birds of northern Black Mesa, Navajo County, Arizona

Two hundred forty-one species of birds have been identified from northern Black Mesa, Arizona. This region's avifauna was poorly known until the late 1970s when large-scale coal mining began. Vegetation of the region is predominantly Great Basin desert scrub, pinyon-juniper woodland, and mixed-conifer woodland. The latter vegetation supports an assemblage of isolated montane bird species unique to the region. Numerous environmental changes have recently affected the bird life of Black Mesa. These include large-scale type conversions (pinyon-juniper clearing and surface mining), pond construction, and establishment of exotic vegetation.     

Genetic analysis of the rare species Salix arizonica (Salicacea) and associated willows in Arizona and Utah

Management decisions affecting the rare plant Arizona willow ( Salix arizonica ) will be aided by understanding genetic similarities among populations of this species. Random Amplified Polymorphic DNA (RAPD) analysis was conducted on 20 populations of S. arizonica , 12 populations of 5 congeners, and 2 samples of outgroup, Populus tremuloides . A phenogram based on DNA markers shows clear separation of populations of S. arizonica from those of co-occurring willow species, but similarity is low (～ 37%) between Utah and Arizona populations of S. arizonica . Evaluation of the relationship of habitat characteristics and geographic distance to genetic similarity reveals that environment and genetic similarity are poorly correlated. Considering Arizona versus Utah populations, we found a significant negative relationship between geographic distance and genetic similarity ( r = 0.936), but no significant relationship between interpopulation distance and genetic similarity within Arizona or Utah. The wide geographic disjunction of S. arizonica populations in Utah and Arizona appears to have existed for a long period during which genetic drift, random mutations, and selection for somewhat different habitats have pushed the 2 regional complexes along separate evolutionary trajectories. Preservation of genetic variation within S. arizonica will require protection of multiple populations in Arizona and Utah.     

Fire frequency and the vegetative mosaic of a spruce-fir forest in northern Utah

Fire scar and vegetative analysis were used to construct a fire history for the Engelmann spruce/subalpine fir ( Picea engelmannii/Abies lasciocarpa ) vegetation type of Utah State University (USU) T. W. Daniel Experimental Forest. Three distinct periods of fire frequency were established-presettlement (1700-1855), settlement (1856-1909), and suppression (1910-1990). Mean fire interval (MFI) decreased during the settlement period and greatly increased during the suppression era. The difference was attributed to the influx of ignition sources during the settlement of nearby Cache Valley, located 40 km to the west. Logging and livestock grazing appear to have led to the reduced MFI, which in turn worked as a factor to create the vegetative mosaic now observed on the study area. The increase in MFI during the suppression ear permitted the advancement of shade-tolerant species in the understory of the shade-intolerant lodgepole pine ( Pinus contorta var. latifolia ) and quaking aspen ( Populus tremuloides ). Continued suppression of disturbance from wildfire will allow the lodgepole pine cover type, which experience the lowest MFI during the settlement period, to be further invaded by shade-intolerant species, decreasing spatial stand diversity and increasing the risk of more intense fires.     

Thermal tolerances and preferences of fishes of the Virgin River system (Utah, Arizona, Nevada)

Critical thermal maxima (CTM) and thermal preferenda of the common fishes of the Virgin River were examined. Differences in final temperature preferenda and CTM for species with low thermal lability (speckled dace, spinedace, roundtail chub) correspond well with differences in their distribution and abundance in the river. These species shifted their acute thermal preferences relatively little as acclimation temperature increased. For thermally labile species (woundfin, red shiner, desert sucker, and flannelmouth sucker), the final preferendum is a less precise indicator of probably distribution. The woundfin, an endangered fish, has a high CTM (39.5 C at 25 C acclimation) and a labile species preferendum (slope nearest 1) compared to other species in the system. The introduced red shiner likewise has a high CTM and a labile acute preferendum. In cooler temperatures, its acute preferendum shifts more rapidly than does that of the woundfin. At higher temperatures (above 15 C), the red shiner does not shift its acute preferendum as rapidly as does the woundfin. The red shiner, however, has a higher final preferendum. For thermally labile species, influence of acclimation temperature on mean preferendum, together with CTM, provides a better insight into distributional relationships within the system.     

Marsilea mollis (Marsileaceae) sporocarps and associated insect parasitism in southern Arizona

We report observations on reproductive phenology, fecundity, and sporocarp morphology for a population of the semiaquatic fern Marsilea mollis B.L. Rob. & Fernald in southern Arizona and document the parasitic relationships of 2 insects collected with the plants. The recently described weevil Notiodes sporocarpicus O’Brien (Coleoptera: Curculionidae) utilizes the fern’s sporocarp as a brood chamber, only the second documented instance of this form of parasitism in the United States. The wasp Lyrcus maculatus (Gahan) (Hymenoptera: Pteromalidae) is a parasitoid of the weevil in this system.     

Observations on the dwarf shrew ( Sorex nanus ) in northern Arizona

Observations of 23 dwarf shrews ( Sorex nanus ) at Fracas Lake in Arizona extend the range of this uncommon shrew northward on the Kaibab Plateau and provide further information regarding the ecology and habitat requirements of this species. Shrews were captured in a previously unreported habitat type (Rocky Mountain montane conifer forest; Brown 1982). This study illustrates the usefulness of intensive, long-term studies and faunal surveys using pitfall traps.     

Some aspects of succession in the spruce-fir forest zone of northern Utah

A site in the Rocky Mountain subalpine forest zone with which a series of hypotheses concerning ecosystem succession was tested is characterized. Succession from herb-dominated meadows to climax forests of Engelmann spruce and subalpine fir can follow at least four identified pathways. After fire, spruce and fir may reinvade a site directly, follow invasion by aspen, or follow invasion by lodgepole pine, the pathway depending on a combination of physical and biotic factors. In other cases, succession begins with long-established meadows which do not owe their existence to fire. In this latter pathway, aspen invades meadows by suckering and changes the environment near the soil surface so as to facilitate establishment of the climax tree species. The biota and soils of four characteristic seral stages (meadow, aspen, fir, spruce-fir) in this latter pathway are described.     

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.     

Douglas-fir tussock moth ( Orgyia pseudotsugata McDunnough) on subalpine fir in northern Utah

Douglas-fir tussock moth ( Orgyia pseudotsugata McDunnough) defoliation was detected by aerial survey on three areas of the Wasatch-Cache National Forest in 1990 and 1991. These are the first documented tussock moth outbreaks in Utah. Ground surveys revealed that subalpine fir ( Abies lasiocarpa [Hook.] Nutt.) was heavily defoliated during the outbreak. Douglas-fir ( Pseudotsuga menziesii [Mirb.] Franco), though minor component in the affected areas, had noticeably less defoliation and mortality. Adjacent stands of Douglas-fir had little or no visible tussock moth activity. Defoliation on subalpine fir was typically found evenly distributed throughout the crown rather than concentrated at the top. Ninety-four percent of subalpine fir with defoliation ratings of 90% or more were killed. Top-kill occurred on nearly one-half of subalpine firs defoliated 25-89%. Heavy defoliated trees tended to occur in pockets bounded by areas of light defoliation. After three consecutive years of defoliation, tussock moth populations collapsed. No life stages were detected in 1993 from visual inspections of foliage or in pheromone traps.     

New Notiodes semiaquatic weevil (Curculionidae) from sporocarps of Marsilea mollis (Marsileaceae) in southern Arizona, USA

A new species from the semiaquatic weevil genus, Notiodes sporocarpicus, which develops and pupates in the sporocarps of the water fern Marsilea mollis B.L. Rob. & Fernald, is described from cattle tanks in southeastern Arizona. This new species can be separated readily from the majority of the known species by its nearly straight rostrum, with its distinctive dorsally swollen base and attenuated apex. Its elongate and slender body will separate N. sporocarpicus from most species in the genus except N. aeratus, which lacks the characters above. The Texas species N. celatus resembles the new species but has strongly developed suberect curved setae that are not present in N. sporocarpicus. Included are habitus photos and line drawings of the male and female genitalia of the new species.     

Western balsam bark beetle, Dryocoetes confusus Swaine, flight periodicity in northern Utah

The flight periodicity of western balsam bark beetle ( Dryocoetes confusus Swaine) in Big Cottonwood Canyon, Utah, was studied during the summer months of 1992, 1993, and 1994. Contents of baited funnel traps were tallied by species up to 3 times weekly. Two main periods of flight activity were observed each year. The first and, generally, largest occurred in early summer soon after flight was initiated for the season. A 2nd period was observed in late summer, generally August. Timing of the 2 periods was influenced by unusually warm or cool weather in each study year. The 1st period had more males than females while the 2nd period had a majority of females. Except during periods of cool or wet weather, western balsam bark beetles were found to be active at least at minimal levels from June through September.