The biological soil crusts of the San Nicolas Island: enigmatic algae from a geographically isolated ecosystem

Composite soil samples from 7 sites on San Nicolas Island were evaluated quantitatively and qualitatively for the presence of cyanobacteria and eukaryotic microalgae. Combined data demonstrated a rich algal flora with 19 cyanobacterial and 19 eukaryotic microalgal genera being identified, for a total of 56 species. Nine new species were identified and described among the cyanobacteria and the eukaryotic microalgae that were isolated: Leibleinia edaphica, Aphanothece maritima, Chroococcidiopsis edaphica, Cyanosarcina atroveneta, Hassallia californica, Hassallia pseudoramosissima, Microchaete terrestre, Palmellopsis californicus, and Pseudotetracystis compactis. Distinct distributional patterns of algal taxa existed among sites on the island and among soil algal floras of western North America. Some algal taxa appeared to be widely distributed across many desert regions, including Microcoleus vaginatus, Nostoc punctiforme, Nostoc paludosum, and Tolypothrix distorta, Chlorella vulgaris, Diplosphaera cf. chodatii, Myrmecia astigmatica, Myrmecia biatorellae, Hantzschia amphioxys, and Luticola mutica. Some taxa share a distinctly southern distribution with soil algae from southern Arizona, southern California, and Baja California (e.g., Scenedesmus deserticola and Eustigmatos magnus ). The data presented herein support the view that the cyanobacterial and microalgal floras of soil crusts possess significant biodiversity, much of it previously undescribed.     

Regional and seasonal diet of the Western Burrowing Owl in south central Nevada

We examined diets of Western Burrowing Owls ( Athene cunicularia hypugaea ) based on contents of pellets and large prey remains collected year-round at burrows in each of the 3 regions in south central Nevada (Mojave Desert, Great Basin Desert, and Transition region). The most common prey items, based on percent frequency of occurrence, were crickets and grasshoppers, beetles, rodents, sun spiders, and scorpions. The most common vertebrate prey was kangaroo rats ( Dipodomys spp.). True bugs (Hemiptera), scorpions, and western harvest mice ( Reithrodontomys megalotis ) occurred most frequently in pellets from the Great Basin Desert region. Kangaroo rats ( Dipodomys spp.) and pocket mice (Perognathinae) were the most important vertebrate prey items in the Transition and Mojave Desert regions, respectively. Frequency of occurrence of any invertebrate prey was high (>80%) in samples year-round but dropped in winter samples, with scorpions and sun spiders exhibiting the steepest declines. Frequency of occurrence of any vertebrate prey peaked in spring samples, was intermediate for winter and summer samples, and was lowest in fall samples. With the possible exception of selecting for western harvest mice in the Great Basin Desert region, Western Burrowing Owls in our study appeared to be opportunistic foragers with a generalist feeding strategy.     

Aquatic Oligochaeta (Annelida: Lumbriculidae, Haplotaxidae, Naididae, Tubificidae) of Utah

Thirty-six species of aquatic Oligochaeta (Lumbriculidae, Haplotaxidae, Naididae, Tubificidae) are now known form Utah. Aquatic habitats in 27 counties were sampled, with 32 oligochaete species identified. An additional 4 species were added from other published investigations. The majority of species are cosmopolitan and occur in other areas of North America. Nais barbata, N. alpina, and N. pardalis are reported from the western United States for the first time. Ilyodrilus frantzi was found to be a major component of the oliogochaete fauna in the Great Basin lentic environment. The North American distribution of Telmatodrilus vejdovskyi is extended significantly eastward. Tow undetermined species of Tubificidae are discussed.     

Distributional information on birds from egg sets collected by Henry Rogers Durkee in 1870 in southwestern Wyoming

Henry Rogers Durkee collected 74 egg sets of 27 avian species in 1870 at Gilmer, Uinta County, in southwestern Wyoming. Despite the paucity of documented breeding evidence from this region during the late 19th and early 20th centuries, his material at the Smithsonian Institution was generally overlooked and has never been critically examined. Durkee's egg sets included 5 species (Sandhill Crane, Grus candensis ; Northern Rough-winged Swallow, Stelgidoteryx serripennis ; Grasshopper Sparrow, Ammodramus savannarum ; Fox Sparrow, Passerella iliaca ; Cassin's Finch, Carpodacus cassinii ) whose breeding distribution was then poorly known, 25 to more than 70 years before nests and eggs were otherwise documented in Wyoming. Durkee also collected complete egg sets of Lark Bunting ( Calamospiza melanocorys ) over 70 years before breeding was confirmed at other peripheral locations in Wyoming. In addition, Durkee's incomplete egg sets of Grasshopper Sparrow were the 1st western subspecies ( A. s. perpallidus ); his complete egg set and nest of the Fox Sparrow collected at Gilmer constituted the 2nd locality for the species or species group ( P. i. schistacea ). Although the number of egg sets Durkee collected is modest, he made a meaningful contribution to the early history of avifaunal exploration in Wyoming.     

Inter-simple sequence repeat (ISSR) variation in three populations of Gaura neomexicana ssp. coloradensis (Onagraceae), F.E. Warren Air Force Base, Cheyenne, Wyoming

We investigated genetic variation within and between 3 populations of Gaura neomexicana ssp. coloradensis , a federally listed threatened species, using inter-simple sequence repeats. The data matrix included 24 individuals scored for 88 bands, with 3.4% missing data. Cluster analysis showed that members of the 3 populations are very similar and are intermixed in the phenogram. Principal coordinate analysis indicated that members of the Crow Creek population are different from the Diamond Creek and ""unnamed drainage"" populations. This could be the result of historic differences, current changes in vegetation at the Crow Creek site, or an artifact of limited sampling. In any case, for management purposes it is best to preserve the dwindling population at Crow Creek as well as the thriving populations at the other 2 sites.     

Demographic and environmental relations of two rare Astragalus species endemic to Washington County, Utah: Astragalus holmgreniorum and A. ampullarioides

Two endemic locoweeds of Washington County, Utah, Astragalus holmgreniorum and A. ampullarioides , were recently listed as federally endangered plant species (Federal Register 2001). They both occur in few, small populations surrounded by increasing human activity in the St. George, Utah, area. Demographic and habitat studies have been ongoing since 1992 and results of those studies are presented here. Astragalus holmgreniorum (Holmgren locoweed) is presently limited to 1 larger population and 2 smaller, isolated populations on the eastern and western edges of its range. It is a short-lived perennial that grows primarily on the Virgin limestone member of the Moenkopi Formation. Density of A. holmgreniorum over the 10-year study averaged about 2 plants per m 2 . The number of living plants of this species perhaps never exceeds 10,000. In drought years A. holmgreniorum populations are as much as 95% smaller than in years with adequate water, and few plants produce flowers that successfully contribute to the seed bank. Astragalus ampullarioides (Shivwits locoweed) occurs in 4 populations where plant density fluctuated between 0.5 and 4.8 per m 2 during our study period (average = 2.6). This locoweed is restricted to clay soils of the Chinle Formation. Direct threats to both Astragalus species include widespread urbanization, road construction, population fragmentation, and off-highway vehicle use. Indirect threats include competition from aggressive, introduced annual species such as Bromus rubens, B. tectorum, Malcolmia africana , and Erodium cicutarium . Our data show that 3 of 4 species most closely associated with these Astragalus species are introduced. Studies of seed banks and reproduction biology, as well as continued monitoring of these Astragalus species, are critically needed. Studies of the consequences of competition from alien and native species on seedling establishment of these locoweeds are especially needed.     

Relationship of diurnal habitat use of native stream fishes of the eastern Great Basin to pPresence of introduced salmonids

Introduced brown trout, Salmo trutta , are common to many streams of western North America. However, the ecological interactions between brown trout and native stream fishes are not well understood, particularly the nature and extent of antipredator responses of native species. We examined the effects of brown trout presence on diurnal habitat use by 2 small native fishes at a mesohabitat scale (e.g., pool, riffle, run, backwater, etc.). Adult and juvenile southern leatherside chub ( Lepidomeda aliciae , formerly Gila copei ) and juvenile mountain sucker ( Catostomus platyrhynchus ) were located in main channel pools in the absence of brown trout, but they were found almost exclusively in backwaters and cutoff pools (i.e., off-channel habitats) in streams where brown trout were abundant. Off-channel habitat appears to provide a refuge for native fishes in streams with abundant brown trout populations. Altered or degraded streams may not include sufficient off-channel refuge habitats to allow coexistence of native species and introduced brown trout.     

Variation in Lewsia kelloggii (Portulacaceae) with description of a new species endemic to Idaho

Lewisia kelloggii has been understood as a rare plant with a disjunct range in California and Idaho. Examination of herbarium specimens and analysis of isozymes in 6 Idaho and 7 California populations revealed consistent differences between plants of the 2 states. Fixed differences in alleles at 2 loci (AAT2 and PGI1) distinguished Idaho from California plants. Genetic identities based on isozymes between Idaho and California populations averaged 0.58, lower than the average for congeneric plant species. Idaho plants were smaller than most California plants, but California plants were variable. The most consistent morphological difference between Idaho and California specimens was the difference in the number of glands on the margins of bracts and sepals. Idaho plants had 0 (-5) pink glands on each margin of these organs, all on teeth near the tips. In California plants these organs had 12-25 glands on each margin, the distal ones elevated on teeth and the proximal ones sessile. We recognize the Idaho plants as a new species, L. sacajaweana , and retain the name L. kelloggii for the California populations.     

Nutritional condition of elk in Rocky Mountain National Park

We tested the hypothesis that elk in Rocky Mountain National Park (RMNP) were at ecological carrying capacity by determining herd-specific levels of nutritional condition and fecundity. Ingesta-free body fat levels in adult cows that were lactating were 10.6% ( s = 1.7; range = 6.2-15.4) and 7.7% ( s = 0.5; range = 5.9-10.1) in November 2001 for the Horseshoe and Moraine Park herds, respectively. Cows that were not lactating were able to accrue significantly more body fat: 14.0% ( s = 1.1; range = 7.7-19.3) and 11.5% ( s = 0.8; range = 8.6-15.1) for the Horseshoe and Moraine Park herds, respectively. Cow elk lost most of their body fat over winter (April 2002 levels were 3.9% [ s = 0.4] and 2.9% [ s = 0.4] for the Horseshoe and Moraine Park herds, respectively). Nutritional condition indicated that both Horseshoe Park and Moraine Park elk were well below condition levels elk can achieve on very good-excellent nutrition (i.e., > 15% body fat; Cook et al. 2004) and were comparable to other free-ranging elk populations. However, condition levels were higher than those expected at a ""food-limited"" carrying capacity, and a proportion of elk in each herd were able to achieve condition levels indicative of very good-excellent nutrition. Elk in RMNP are likely regulated and/or limited by a complex combination of density-independent (including significant heterogeneity in forage conditions across RMNP's landscape) and density-dependent processes, as condition levels contradict a simple density-dependent model of a population at ecological carrying capacity.     

Exotic plants in early and late seral vegetation of fifteen northern Rocky Mountain environments (HTs)

We determined the capacity of exotic plants to invade major environmental types of the northern Rocky Mountains. We did this by observing their presence on disturbed and undisturbed sites in relatively well inoculated locations--corridors adjacent to highways--on transects across the mountains in Glacier National Park and Grand Teton National Park and on low-altitude sites between them. We draw 3 primary conclusions. First, of 29 exotics commonly found, the most dominant are intentionally introduced grasses ( Agrostis, Bromus, Dactylis , and especially Phleum pratense and Poa pratensis ) and legumes ( Melilotus, Medicago , and Trifolium ) rather than the forbs more often listed as noxious. Second, in the environmental types studied, disturbed sites are invasible, except in the alpine. Third, invasion of undisturbed sites declines from grasslands and open forests to alpine to moist forests. This gradient probably represents a decline in resource (light, water, nutrients) availability for herbs, except in the alpine, where a physical limitation is suggested by the poor performance of exotics on noncompetitive disturbed sites.