Summer food habits of a small mammal community in the pinyon-juniper ecosystem

Summer food habits of a small mammal community in the Piceance Basin of Colorado were investigated during 1977 and 1978 using a combination of fecal and stomach content analyses. Three species, deer mice ( Peromyscus maniculatus ), least chipmunks ( Eutamias minimus ), and plains pocket mice ( Perognathus flavescens ) consumed arthropods as the majority of their diets. Bushy-tailed woodrats ( Neotoma cinerea ) consumed predominantly woody vegetation, and the diet of golden-mantled ground squirrels ( Spermophilus lateralis ) consisted primarily of forbs and fungi. Mountain cottontails ( Sylvilagus nuttalli ) depended heavily on grasses, with a mix of woody vegetation and forbs composing the remainder of their diet. Most of the species investigated selected different foods and thus avoided competition for food. Plains pocket mice may have competed with deer mice for arthropods in 1977.     

Late Quaternary vegetation and climate in the Escalante River Basin on the central Colorado Plateau

Five alcoves (rock shelters) in the Forty-Mile Canyon—Willow Gulch area of the Escalante River Basin in southeastern Utah yielded rich deposits of late Quaternary macrobotanical remains. The deposits were sampled and the contents identified in order to construct a chronology of vegetational change. Fourteen radiocarbon dates indicate that the fossils were deposited between 12,690 and 7510 yr B.P. (years before present). Ninety-one plant taxa were identified, 62 to species. Six species were common to all alcoves: Gambel oak ( Quercus gambelii ), box-elder ( Acer negundo ), prickly pear ( Opuntia subgenus Platyopuntia), skunkbush ( Rhus aromatica var. trilobata ), serviceberry ( Amelanchier utahensis ), and Indian ricegrass ( Oryzopsis hymenoides ). Late Pleistocene samples (>11,000 yr B.P.) contain extralocal, elevationally depressed species such as Douglas fir ( Pseudotsuga menziesii ), spruce ( Picea sp.), and mountain mahogany ( Cercocarpus ledifolius ), and mesophytic species such as rose ( Rosa woodsii ) and water birch ( Betula occidentalis ). Early Holocene samples (11,000-8000 yr B.P.) contain no elevationally depressed conifers, and the remaining mesophytic species decrease in relative abundance. Reticulated hackberry ( Celtis reticulata ) becomes common. The terminal Early Holocene sample (8000-7000 yr B.P.) contains abundant Gambel oak and prickly pear, but little else. Paleoclimatic interpretations for the Late Pleistocene correspond well to those of most other workers on the Colorado Plateau. Climates that were wetter and at least seasonally cooler than they are today are inferred from the macrobotanical assemblage. However, the increased moisture is attributed to higher stream base levels and increased groundwater rather than directly to increased precipitation. Early Holocene climates are interpreted as warmer and drier than those of the Late Pleistocene but still wetter than the present climate. Groundwater levels appear to be decreasing due to stream entrenchment. Terminal Early Holocene climates were much warmer and at least seasonally drier. By the end of the period, groundwater levels had decreased so much that the alcoves were unable to sustain plant communities; stream base level was probably near the present level.     

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.     

Plant adaptation in the Great Basin and Colorado Plateau

Adaptive features of plants of the Great Basin are reviewed. The combination of cold winters and an arid to semiarid precipitation regime results in the distinguishing features of the vegetation in the Great Basin and Colorado Plateau. The primary effects of these climatic features arise from how they structure the hydrologic regime. Water is the most limiting factor to plant growth, and water is most reliably available in the early spring after winter recharge of soil moisture. This factor determines many characteristics of root morphology, growth phenology of roots and shoots, and photosynthetic physiology. Since winters are typically cold enough to suppress growth, and drought limits growth during the summer, the cool temperatures characteristic of the peak growing season are the second most important climatic factor influencing plant habit and performance. The combination of several distinct stress periods, including low-temperature stress in winter and spring and high-temperature stress combined with drought in summer, appears to have limited plant habit to a greater degree than found in the warm deserts to the south. Nonetheless, cool growing conditions and a more reliable spring growing season result in higher water-use efficiency and productivity in the vegetation of the cold desert than in warm deserts with equivalent total rainfall amounts. Edaphic factors are also important in structuring communities in these regions, and halophytic communities dominate many landscapes. These halophytic communities of the cold desert share more species in common with warm deserts than do the nonsaline communities. The Colorado Plateau differs from the Great Basin in having greater amounts of summer rainfall, in some regions less predictable rainfall, sandier soils, and streams which drain into river systems rather than closed basins and salt playas. One result of these climatic and edaphic differences is a more important summer growing season on the Colorado Plateau and a somewhat greater diversification of plant habit, phenology, and physiology.     

Observations on Recruitment and Ecology of Razorback Sucker: Lower Colorado River, Arizona-California-Nevada

The Colorado River system downstream from Lake Mohave yielded 42 adult, 19 juvenile, and 39 larval wild razorback suckers ( Zyrauchen texanus ) between 1962 and 1988. Forty-six additional young captured between 1984 and 1987 may have been wild or stocked, hatchery-propagated fish. Wild juveniles of this endemic, imperiled species, with one exception, have not been otherwise known from the Colorado River basin downstream from the Grand Canyon since the 1950s. A majority of adults and larvae were from the river or its mainstream impoundments, while all but one wild juvenile and all presumably stocked fish were captured from irrigation canals. The ecology of artificial canals in which young razorback suckers survive and grow is poorly understood.     

Floristic analysis of the southwestern United States

A study was made of the distributions of native, terrestrial, vascular plants occurring in 50 local floras from throughout the Basin and Range and Colorado Plateau physiographic provinces of the southwestern United States. The objectives of the study were to objectively define and describe the floristic elements-assemblages of species with roughly coincident geographic distribution-occurring in the southwestern United States and to determine what such assemblages reveal about the floristic history of the region. The total flora (native, terrestrial species only) of the Southwest is estimated at 5,458 species, 77% of which were recorded in 1 or more of the local floras. Nearly 22% of these species are endemic to the study region. A majority of the species were found to be relatively rare. The average range of a species included only 4 floras, and 90% of the species were recorded from 11 or fewer floras; only 81 species (1.5%) were recorded from 50% or more of the floras. Trees constitute 2% of the regional flora and have the widest average distribution; perennial herbs constitute 59% of the flora and have the most restricted distributions.  Factor analysis was used to identify seven floristic elements for the region: a Great Basin element, a Mojavean element, a Colorado Plateau element, a Chihuahuan element, an Apachian element, and a Mogollon element. This factor analysis solution was shown to satisfy criteria of interpretability and consistency. The Mojavean, Colorado Plateau, and Apachian elements are believed to be autochthonous. The other four elements show high overlap in species composition with one or more adjacent regions. Each floristic element is mapped to show its geographic form and distribution. Analysis of these maps shows how the existence of objectively defined floristic elements is not contradictory to either the individualistic view of the distribution of a species or local continuity of vegetation and flora. The rarity of the majority of species and the clear association of floristic elements with rather narrowly circumscribed Holocene environments suggests that many Southwestern species have migrated little and are of rather recent, probably postglacial origin. Geographic “principles” derived from the distribution patterns of relatively few, widespread, dominant, usually woody species may not be applicable to entire, regional floras.       

In memoriam: Seville Flowers (1900-1968)

Seville Flowers was the foremost authority of his time on cryptogamic botany in the intermountain region, having published monographs on the mosses, lichens, and ferns of Utah. He also had strong interests in algae, grasses, composites, and the history of botany. In addition to his systematic research, his expertise extended to field ecology. Early in his career he made a classic study of the vegetation of the Great Salt Lake region that led in later years to his participation in the ecological studies at Dugway Proving Grounds in western Utah. Still later he had charge of the predam vegetative surveys of several reservoir sites along the Upper Colorado River, including Glen Canyon, which was later submerged under Lake Powell. He served as professor of botany at the University of Utah from 1936 to 1968. His professional career started in 1929. A bibliography of his writings is included in this account of his life and professional career.      

Chironomidae (Diptera) of the Colorado River, Grand Canyon, Arizona, USA, I: systematics and ecology

We describe the chironomid midge fauna of the Colorado River between Glen Canyon Dam and Lake Mead, Arizona. This depauperate fauna, consisting of 38 species, is dominated by euryecious Nearctic or Holarctic orthocladine taxa. In addition, a small Neotropical faunal component is represented by Polypedilum obelos Sublette & Sasa and Rheotanytarsus hamatus Sublette & Sasa. The following new synonyms are given: Protenthes riparius Malloch 1915 with Tanypus bellus Loew 1866 [= Procladius (Psilotanypus) bellus (Loew)]; Cricotopus olivetus Boesel 1983 with Cricotopus (Circotopus) annulator (Goetghebuer) 1927; Cricotopus edurus Sublette & Sublette 1971 with Orthocladius infuscatus Malloch 1915 [= Cricotopus (Cricotopus) infuscatus (Malloch)]. The following new species are described: Cricotopus (Cricotopus) blinni Sublette, Cricotopus (Cricotopus) hermanni Sublette, Metriocnemus stevensi Sublette, and Cladotanytarsus marki Sublette. We discuss the distribution and ecology of each chironomid species in this large, regulated, aridlands river.     

Fossil history of Notiosorex (Soricomorpha: Soricidae) shrews with descriptions of new fossil species

Notiosorex shrews (Soricomorpha: Soricidae) have a fossil history that extends to the Miocene (i.e., mid-Hemphillian). In the intervening 6.69 million years, N. repenningi, N. jacksoni, and what heretofore was considered N. crawfordi existed with varying degrees of overlap in occurrence timewise and in geographic distribution in areas of the southwestern United States and northern Mexico. Examination of unusually small fossil specimens of Notiosorex indicated the presence of another species referable to this genus present in late Pleistocene- (i.e., early Wisconsinan) to Holocene-aged deposits. Based on statistical analyses, these specimens were as distinct from any of the other fossil or extant species of Notiosorex as any other pair of species within the genus. I referred these specimens to the new species N. harrisi. Analyses also indicted fossils heretofore considered N. crawfordi were equally distinct from other forms of Notiosorex. I referred them to the new species N. dalquesti. Individuals referred to the fossil species of Notiosorex range in size from the smaller N. harrisi, to N. dalquesti, to N. jacksoni, to the larger N. repenningi. This size differential could be related to changing climatic conditions with the concomitant ecological succession that occurred, which provided a driving force for speciation within the genus. The changing climate and unique morphological and physiological adaptations allowed fossil taxa of Notiosorex to expand their distributions into areas subsequently less suitable for other forms of shrews. Present-day notiosoricini shrews occur throughout much of the southwestern United States and northern Mexico in a variety of habitats in association with rough, rocky terrain. Thus, if climate, even indirectly, was the driving force for speciation among fossil taxa of Notiosorex, other forces must have acted on the extant species N. cockrumi, N. crawfordi, N. evotis, and N. villai.     

Asian tapeworm ( Bothriocephalus acheilognathi ) in native fishes from the Little Colorado River, Grand Canyon, Arizona

Examination of gastrointestinal tracts of native cyprinids from the Little Colorado River (LCR) in Grand Canyon, Arizona, 1990-1994, revealed varying rates of prevalence and infrapopulation levels of Asian tapeworm ( Bothriocephalus acheilognathi ). Mean prevalence was 28% (range 0-78%) in humpback chub ( Gila cypha ) and 8% (range 0-46%) in speckled dace ( Rhinichthys osculus ), with infrapopulations as high as 46 and 28, respectively. We also note Asian tapeworm infection of nonnatives common carp ( Cyprinus carpio ), fathead minnow ( Pimephales promelas ), and plains killifish ( Fundulus zebrinus ) from the LCR. Reported pathogenic and chronic effects of this cestode to its definitive hosts add concern for the status of the Grand Canyon population of the federally endangered humpback chub. The rapidity which Asian tapeworm has spread to different drainages of the Colorado River Basin likely portends an eventual cosmopolitan basin distribution in lower elevations suitable to the parasite's thermophilic life history. Such biotic changes must be considered among the most serious threats to conservation and recovery of native fish populations.     

Home-range fidelity and use of historic habitat by adult Colorado pikeminnow ( Ptychocheilus lucius ) in the White River, Colorado and Utah

Twelve wild adult Colorado pikeminnow ( Ptychocheilus lucius ), captured in the tailwaters of Taylor Draw Dam on the White River, Colorado, were implanted with radio transmitters and their movement patterns monitored from 1992 to 1994. The spawning migration of these fish was extensive. In 1993, the only full year of the study, the fish migrated an average of 658 km from the White River to spawning sites in the Yampa or Green rivers and back to the White River. Eight of these fish were translocated in the river upstream of the dam in April 1993. These fish and the 4 others below the dam remained in the river until May 1993. All 12 had migrated down the White River to spawning sites in the Green and Yampa rivers by July 1993. The fish that were located above the dam successfully passed over the dam during their downstream migration. Seven fish migrated upstream toward the Yampa River Canyon spawning site and 5 migrated downstream toward the Green River Desolation/Gray Canyon spawning site. Five of 7 Yampa River fish were found at the spawning site. The other 2 were found 5-8 km downstream of the site. One of 5 Green River fish was found at the spawning site, the other 4 between 16 and 62 km upstream of the site. All fish migrated back to the White River by August 1993 and were found near the dam by October 1993. Two fish were recaptured and translocated above the dam in September 1993. Five fish were located below the dam and 2 above the dam in April 1994. By July 1994 seven of the same fish that had migrated toward the Yampa River in 1993 were found at the Yampa Canyon spawning site. At the same time, 3 of 5 fish that migrated toward the Green River in 1993 were found at the Desolation/Gray Canyon spawning site. This included 2 fish that had been found upstream of the site in 1993. The 12 fish traveled an average of 6 km d -1 (range: 4-10 km d -1 ) during the migration period from May through October 1993. Generally, fish moved faster to the spawning site than back from the site to the White River. These fish moved very little within their home ranges in the White River. Six fish tagged in 1992 moved only 0.1-2.3 km in the tailwater reach below Taylor Draw Dam from September 1992 through April 1993. All fish, after their spawning runs, had moved up to or near the dam by October 1993. These fish were not tracked again until April 1994. Their movement patterns in April 1994 were similar to those observed in April 1993. The greatest amount of fish movement in the White River was displayed by the 8 fish placed above Taylor Draw Dam in April 1993 and the 2 placed in Kenney Reservoir in September 1993. They moved 1.1-40.6 km in the river before and after their spawning migration in spring and autumn 1993. These spawning migrations suggest that adult Colorado pikeminnow in the White River were recruited from both Green and Yampa river spawning populations and were presumably imprinted to these respective spawning sites. Those fish placed above Taylor Draw Dam established home ranges in habitats previously occupied by Colorado pikeminnow before the dam was completed. They remained there until they migrated downstream during the spawning period. Although we did not study fish passage, our study demonstrates that adult Colorado pikeminnow will use habitat if access is provided. Translocation of wild adult fish into historic but unoccupied habitats may be a valuable recovery option.     

Distribution of Brechmorhoga clubskimmers (Odonata: Libellulidae) in the Grand Canyon region, southwestern USA

We examined the distribution of Brechmorhoga mendax and B. pertinax (Libellulidae) in northern Arizona and southern Nevada. Brechmorhoga mendax occurs widely throughout the Southwest and in Arizona up to the Mogollon Rim, and up the Colorado River from the west to at least River Mile 132 (downstream from Lees Ferry, Arizona) at elevations of 110-1460 m. In Grand Canyon it occurs along small to large tributaries and on the mainstream at elevations below 650 m. The only previously reported locality for B. pertinax in the United States is in southeastern Arizona, where it was presumed to be accidental. We report B. pertinax along 5 small, perennial tributaries emanating from Redwall Formation aquifer springs on the south side of central Grand Canyon. Those springs habitats may be threatened by regional groundwater depletion. Brechmorhoga pertinax appears to be somewhat more stenotolerant in its habitat requirements than B. mendax , a finding in keeping with these differences in range. The presence of isolated populations of B. pertinax in Grand Canyon is an example of a Neotropical influence on the fauna and indicates biogeographic corridor and refuge functions of this large, deep canyon.     

Late quaternary plant zonation and climate in southeastern Utah

Plant macrofossils from packrat middens in two southeastern Utah caves outline development of modern plant zonation from the late Wisconsin. Allen Canyon Cave (2195 m) and Fishmouth Cave (1585 m) are located along a continuous gradient of outcropping Navajo Sandstone that extends from the Abajo Mountains south to the San Juan River. By holding the site constant, changes in the floral composition for a plot of less than one hectare can be observed, even if sporadically, over tens of millennia. At Allen Canyon Cave, Engelmann spruce-alpine fir forest was replaced by the present vegetation consisting of pinyon-juniper woodland on exposed ridgetops and cliffside stands of Douglas fir, ponderosa pine, and aspen. Xerophytic woodland plants such as pinyon, plains prickly pear, and narrowleaf yucca arrived sometime in the middle Holocene between 7200 and 3400 B.P. At Fishmouth Cave, Utah juniper in Holocene middens replaced blue spruce, limber pine, Douglas fir, and dwarf and Rocky Mountain junipers in late Wisconsin samples. Disharmonious associations for the late Wisconsin occur only at the lower site with the xerophytes Mormon tea, plains prickly pear, and narrowleaf yucca growing alongside subalpine conifers. One possible explanation involves the late Wisconsin absence of ponderosa and pinyon pines from the Colorado Plateaus. Released from competition at their lower limits, subalpine conifers were able to expand into lower elevations and mix with xerophytic plants found today in understories of pinyon-juniper and ponderosa pine woodlands. Quantitative climatic estimates are derived for the late Wisconsin by applying vertical gradients for temperature and precipitation to the amount of vegetation depression. The Fishmouth Cave sequence indicates a minimum lowering of 850 m for blue spruce, limber pine, and dwarf juniper. A depression of at least 700 m for Engelmann spruce and alpine fir is suggested for the Allen Canyon locality. Use of conservatively low gradients for stations below 2080 m yields a 3–4 C cooling from present mean annual temperature and 35 to 60 percent more rainfall than today. Steeper gradients associated with more mountainous terrain suggest a 5 C lowering in temperature and up to 120 percent increase over modern precipitation.        

Checklist of vascular plants for the Bighorn Canyon National Recreation Area

The checklist of vascular plants of Bighorn Canyon National Recreation Area is presented based on field collections and herbarium specimens. The checklist treats 656 taxa from 73 families.         

Flora of the Orange Cliffs of Utah

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The vascular flora of the Orange Cliffs area, defined here as part of the Colorado Plateau floristic province, harbors approximately 209 species in 123 genera and 49 families. A species checklist is provided with a discussion of physical and floristic aspects of the region. The flora is compared statistically to the San Rafael Swell flora, which is also a subset of the Colorado Plateau. We define six vegetation types and three edaphic communities; these are described and mapped. Of eleven endemic plant species in the Orange Cliffs, three are local and rare. Sites for Astragalus nidularius, A. moencoppensis, and Xylorhiza glabriuscula var. linearifolia are discussed and mapped.     

Red Butte Canyon Research Natural Area: history, flora, geology, climate, and ecology

Red Butte Canyon is a protected, near pristine canyon entering Salt Lake Valley, Utah. It contains a well-developed riparian zone and a perennial stream; hillside vegetation ranges from grasslands on the lower limits to Douglas-fir and aspen stands at the upper elevations. In this paper we describe the history of human impact, natural history aspects of climate, geology, and ecology, and faunal and floral information for key species in the canyon. The role and importance of Research Natural Areas is discussed, particularly with respect to the need to protect Red Butte Canyon:one of the few remaining undisturbed riparian ecosystems in the Intermountain West.     

Chironomidae (Diptera) of the Colorado River, Grand Canyon, Arizona, USA, II: factors influencing distribution

Biogeographic, flow regulation (water clarity and temperature), and temporal influences affect the composition of the chironomid midge assemblage in the Colorado River between Glen Canyon Dam and Lake Mead. This assemblage is dominated by euryecious Nearctic and Holarctic orthocladine taxa (23 of 38 total species, total weighted relative abundance [WRA] = 0.972) and includes a minor Neotropical component. Chironomid species richness increases over distance downstream from the dam, and dominance shifts across 3 turbidity segments. Eleven species occur in the cold-stenothermic Clearwater (CW) segment between the dam and the 1st perennial tributary (the Paria River, 26 km from the dam). Chironomid diversity increases from 18 to 24 species in the variably turbid (VT) and usually turbid (UT) segments downstream, respectively. Total Cricotopus spp. WRA is negatively correlated with distance (turbidity), white total Chironominae WRA shows the opposite pattern. In contrast to chironomid diversity, species density decreases from 0.42 species/km in the CW segment to 0.19 and 0.08 species/km in the VT and UT segments, respectively. Seasonal dominance shifts slightly from orthocladine Eukiefferiella spp. in winter (WRA = 0.101) to Cricotopus spp. (WRA = 0.165) in summer. Total WRA is lowest in spring (0.191). The assemblage is depauperate compared with other western rivers and has changed over post-dam time.     

Seasonal patterns of arthropod diversity and abundance on big sagebrush, Artemisia tridentata

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.     

Symbos cavifrons (Artiodactyla: Bovidae) from Delta County, Colorado

A partial cranium belonging to the extinct woodland musk - ox, Symbos cavifrons, is reported from the headwaters of Oak Creek, Delta County, Colorado. This is the first cranium of the genus Symbos to be described from the Colorado Plateau, and it helps to define the southwest boundary of the known range of the genus.