Relationship between cheatgrass coverage and the relative abundance of snakes on Antelope Island, Utah

Cheatgrass ( Bromus tectorum ) is an invasive annual known to negatively impact many shrub-dependent organisms; however, relatively little research has examined how it affects snake communities. Bromus tectorum is abundant at Antelope Island State Park, Davis County, Utah, and could be a possible threat to snake populations. Study sites representing different B. tectorum coverage percentages were established to measure relative abundance of snakes. Snakes were captured from June to September 2005 primarily by using funnel traps attached to drift-fence arrays. Linear regression revealed a negative relationship between B. tectorum coverage (%) and the relative abundance of the Great Basin gopher snake ( Pituophis catenifer deserticola ) and the western racer ( Coluber mormon ). These results (1) suggest that B. tectorum invasions result in reduced snake abundance in shrubsteppe habitat on Antelope Island and (2) add to our understanding of the relationships between B. tectorum and native fauna.     

Spatial patterns of plant communities and differential weathering in Navajo National Monument, Arizona

Vegetation patterns in Navajo National Monument, Arizona, were studied over a five-year period from 1977 to 1981. Twelve distinct plant community types occur within the boundaries of the park. These communities are characterized and the dominant plant species of each are recorded. The relationships of parent material, soils, and moisture to plant communities are also discussed. It appears that discrete communities occupy soils of different characteristics, particularly with respect to amount of weathering of parent material.         

Ecological investigation of a suspected spawning site of Colorado squawfish on the Yampa River, Utah

On 5 July 1981, 13 adult Colorado squawfish were found in spawning condition at river mile 16.5 in the Yampa River, a major tributary to the Green River. An investigation was undertaken to quantitatively describe this section of the river to gain insights on the spawning requirements of this endangered species. The substrate at the suspected spawning site was cobble with large interstitial spaces devoid of organics, silts, or clays. It appeared that larvae of several fish species utilized these cobble areas and the associated voids. Diurnal sampling indicated that larval drift occurred between 0100 and 0125 hours. Substrate size also appeared to be a dominant factor in fish distribution. Feeding intensities of these fish corresponded to macroinvertebrate drift.         

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.     

A checklist of the alpine vascular flora of the Teton Range, Wyoming, with notes on biology and habitat preferences

A checklist of the vascular flora of the alpine zone (treeless vegetation above 9500 feet or 2900 m) of the Teton Range is presented. For each of the 216 species, six attributes are listed: flower color and shape, pollination mode, life form, habitat preference, and whether each species is found in the Arctic. White and yellow flowered species are most common, and zoophilous species greatly predominate over anemophilous and apomictic species. Perennial/biennial herbs are the most common life form. Common habitats in the alpine zone include dry and wet meadows, bogs, debris accumulations, and cliffs and rock faces. Arctic species account for 25.9 percent of the flora. The 216 species are distributed among 111 genera and 36 families. The largest families, in order of size, are Asteraceae, Poaceae, Cyperaceae, Brassicaceae, Rosaceae, and Scrophulariaceae.     

Predator-specific mortality of pronghorn on Yellowstone’s northern range

Yellowstone National Park supports a small population ( Antilocapra americana ). Some individuals migrate during summer to areas characterized by reduced visibility, mixed habitat types, and a diverse predator community. Across areas selected by migratory and nonmigratory pronghorn, we documented cause-specific mortality of adults and fawns and assessed relative risk of predation by various predators. Coyotes ( Canis latrans ) accounted for 56% of adult predation and up to 79% of fawn predation. Cougars ( Puma concolor ) and wolves ( Canis lupus ) accounted for additional predation of adults, while cougars, black bears ( Ursus americanus ), and Golden Eagles ( Aquila chrysaetos ) were documented killing fawns on rare occasions. Our results suggest that even when pronghorn are in the presence of multiple predator species, coyote predation on adults and fawns may predominate for populations inhabiting shrubsteppe habitat. However, the risk of predation by sympatric predators, particularly cougars, may be high for female pronghorn selecting mixed cover types during migration or for birthing purposes. While the direct effect of wolves on overall mortality was low, wolves may indirectly influence survival rates of adult females and fawns by altering the behavior and space use of sympatric predators, particularly coyotes.     

Aquatic and semiaquatic Heteroptera of the Grand Canyon (Insecta: Hemiptera)

The aquatic and semiaquatic Hemiptera from 12 localities in Marble Canyon and Grand Canyon are reported, along with those from 1 locality in the Escalante Canyon. Fourteen species are recorded and compared to the water-bug fauna of the southwestern United States and western Mexico. Ochterus rotundus n. sp. is described from the Grand Canyon and the mountains of western Mexico.     

The austrina group of the genus Microvelia (Hemiptera: Veliidae)

Six new species of Microvelia are described from North and Central America: depressus, glabrosulcata, leavipleura, paura, psilonota, and reflexus. These species are compared to Microvelia austrina Bueno, and the austrina group is designated to hold them. The habitats and phoresy of the group are discussed.     

Soil microstructure in soils of the Colorado Plateau: the role of the cyanobacterium Microcoleus vaginatus

The role of the cyanobacterium Microcoleus vaginatus in cold-desert soil crusts is investigated using scanning electron microscopy. Crusts from sandstone-, limestone-, and gypsum-derived soils are examined. When dry, polysaccharide sheath material from this cyanobacterium can be seen winding through and across all three types of soil surfaces, attaching to and binding soil particles together. When wet, sheaths and living filaments can be seen absorbing water, swelling and covering soil surfaces even more extensively. Addition of negatively charged material, found both as sheath material and attached clay particles, may affect cation exchange capacity of these soils as well. As a result of these observations, we propose that the presence of this cyanobacterium may significantly enhance soil stability, moisture retention, and fertility of cold-desert soils.