Digital Commons Network^™

Western Scrub-Jay Breeding Biology In Central Colorado, Kerri Vierling, Barbara L. Winternitz

Western North American Naturalist

The breeding ecology of the Western Scrub-Jay (Aphelocoma californica) in the midwestern United States is relatively unknown compared with Aphelocoma species in other geographic regions. We examined Western Scrub-Jay breeding biology in Colorado between 1970 and 1992. Incubation was initiated in early April and lasted 16 days, while the nestling stage lasted approximately 17-18 days. Clutch size averaged 4.0 eggs per nest, reproductive success was 25%, and productivity averaged 0.66 fledglings per nest. The low reproductive success and productivity measures may be due to high predator densities in the surrounding suburban landscape. Western Scrub-Jays preferred nesting in eastern …

Responses Of Opossums And Raccoons To Bobcat And Coyote Feces, Philip S. Gipson, Troy R. Livingston, Gerald L. Zuercher, Mark E. Howard

Western North American Naturalist

No abstract provided.

A New Record Of Heribaudiella Fluviatilis, A Freshwater Brown Alga (Phaeophyceae), From Oregon, John D. Wehr, Alissa A. Perrone

Western North American Naturalist

Members of the algal class Phaeophyceae (brown algae) are almost entirely marine species. A few genera have been described from freshwater habitats, but their distribution and ecological requirements, especially in North America, are very poorly known. The 1st specimens of a freshwater species of brown algae from Oregon, Heribaudiella fluviatilis, were discovered in 3 localities of the McKenzie River, near McKenzie Bridge and Belknap Springs (44°22′N, 122°00′-15′W). This is the 4th extant population of this species known from the United States. The alga forms distinctive, macroscopic, dark brown patches on rocks in rapidly flowing water. In the McKenzie River …

Efficacy Of Photographic Scent Stations To Detect Mountain Lions, Eric S. Long, Dorothy M. Fecske, Richard A. Sweitzer, Jonathan A. Jenks, Becky M. Pierce, Vernon C. Bleich

Western North American Naturalist

No abstract provided.

Reproductive Ecology Of Dusky Flycatchers In Montane Meadows Of The Central Sierra Nevada, James W. Cain Iii, Michael L. Morrison

Western North American Naturalist

Avian species with expansive ranges or those that occupy more than one vegetative association may vary in aspects of their life histories across their ranges. The distribution of Dusky Flycatchers encompasses a variety of vegetative associations, including riparian communities. However, much of the literature on this species details studies conducted in upland areas. Our objectives were to describe the breeding ecology and fecundity of Dusky Flycatchers nesting in montane meadows of the central Sierra Nevada, California. We monitored 36 territories and located 37 Dusky Flycatcher nests in 8 meadows. Average clutch size was 3.9 eggs. Egg laying, incubation, and nestling …

Arbuscular Mycorrhizae In Thermal-Influenced Soils In Yellowstone National Park, Rebecca A. Bunn, Catherine A. Zabinski

Western North American Naturalist

Mycorrhizae are common plant-fungal symbioses occurring in most land plants. Despite their ubiquity, little is known about the distribution of arbuscular mycorrhizae (AM) in extreme environments. We surveyed for the presence of AM in thermal sites in Yellowstone National Park (YNP) where soils are characterized by extreme pHs, elevated temperatures, and toxic element concentrations. Plants at 5 sites, growing in soils with rooting-zone temperatures up to 48°C and soil pH values as low as 3.4, were mycorrhizal (colonization levels from 4% to 34%). Soils from a sparsely vegetated thermal area and an adjacent, continuously vegetated transition area differed significantly in …

Plant Invasions In Protected Areas At Multiple Scales: Linaria Vulgaris (Scrophulariaceae) In The West Yellowstone Area, Aníbal Pauchard, Paul B. Alaback, Eric G. Edlund

Western North American Naturalist

Invasive alien plants have long been recognized as a threat to low-elevation, disturbed environments, but the case of Linaria vulgaris Mill. in Yellowstone National Park and Gallatin National Forest shows that invasions can also spread to high-elevation natural reserves. Because invasions in protected areas are a product of complex processes occurring over a broad range of scales, we argue that a multi-scale research approach is needed to capture both patterns and potential mechanisms of the invasion process. Mapping L. vulgaris at the landscape scale, we found the species occupying a broad range of sites, apparently originating from just 2 historical …

Nesting And Brood-Rearing Characteristics Of Chukars In West Central Idaho, Andrew J. Lindbloom, Kerry P. Reese, Peter Zager

Western North American Naturalist

We analyzed attributes from 23 nests (10 renests) and 46 brood locations of radio-marked Chukars (Alectoris chukar) in the lower Salmon River canyon of west central Idaho in 1995 and 1996. Nesting effort was 100%, apparent nest success was 45%, and estimated time from destruction or abandonment of a nest to initiation of laying a subsequent nest averaged 13 ± 5 days s_x. Average clutch size for 1st nests (14.5 ± 1.0) was greater (P = 0.017) than renests (10.4 ± 1.1). Cover types used by nesting Chukars included grass/forb (48% of nests), rock (43%), …

Attributes Associated With Probability Of Infestation By The Piñon Ips, Ips Confusus (Coleoptera: Scolytidae), In Piñon Pine, Pinus Edulis, José F. Negrón, Jill L. Wilson

Western North American Naturalist

We examined attributes of piñon pine (Pinus edulis) associated with the probability of infestation by piñon ips (Ips confuses) in an outbreak in the Coconino National Forest, Arizona. We used data collected from 87 plots, 59 infested and 28 uninfested, and a logistic regression approach to estimate the probability of infestation based on plot and tree-level attributes. Piñon pine stand density index was a good predictor of the likelihood of infestation by piñon ips at the plot level, and a cross-validation analysis confirmed that the model correctly classified 82% of the cases. Diameter at root collar …

Soil Properties Associated With Vegetation Patches In A Pinus Ponderosa–Bunchgrass Mosaic, Becky K. Kerns, Margaret M. Moore, Michael E. Timpson, Stephen C. Hart

Western North American Naturalist

Since Euro-American settlement, fire exclusion and other factors have dramatically altered interior western coniferous forests. Once open and parklike, present-day structure in many southwestern Pinus ponderosa forests consists of dense stands of young, small-diameter trees, with small patches of larger, old trees, and relict open bunchgrass areas. Our objectives were to assess differences in soil properties associated with these different vegetation patches. We examined soil morphological characteristics, pH, organic C concentration, total N concentration, C:N ratio, and phytolith concentration from profiles within 6 transects (18 soil pedons) crossing patches of dense stands of small diameter trees, patches of old-growth trees, …

Beaver Herbivory Of Willow Under Two Flow Regimes: A Comparative Study On The Green And Yampa Rivers, Stewart W. Breck, Kenneth R. Wilson, Douglas C. Andersen

Western North American Naturalist

The effect of flow regulation on plant-herbivore ecology has received very little attention, despite the fact that flow regulation can alter both plant and animal abundance and environmental factors that mediate interactions between them. To determine how regulated flows have impacted beaver (Castor Canadensis) and sandbar willow (Salix exigua) ecology, we first quantified the abundance and mapped the spatial distribution of sandbar willow on alluvial sections of the flow-regulated Green River and free-flowing Yampa River in northwestern Colorado. We then established 16 and 15 plots (1 m x 2.7 m) in patches of willow on the …

High Nitrogen Availability Does Not Improve Salinity Tolerance In Sarcobatus Vermiculatus, Rebecca E. Drenovsky, James H. Richards

Western North American Naturalist

Natural and anthropogenic changes in basin lake levels in the western U.S. expose saline, alkaline substrates that are commonly colonized by shrubs in the Chenopodiaceae. On a chronosequence of recently exposed substrates at Mono Lake, California, Sarcobatus vermiculatus has greatest biomass accrual, seed production, seedling establishment, and leaf N at younger sites where soils are extremely saline and alkaline. These field observations and an understanding of the role of N-containing compatible solutes in salinity tolerance of halophytes led to our prediction that Na and N interactions stimulate Sarcobatus performance. To test this, we grew Sarcobatus juveniles for 2 years in …

Habitat Features And Predictive Habitat Modeling For The Colorado Chipmunk In Southern New Mexico, Marina Rivieccio, Bruce C. Thompson, William R. Gould, Kenneth G. Boykin

Western North American Naturalist

Two subspecies of Colorado chipmunk (state threatened and federal species of concern) occur in southern New MeXico: Tamias quadrivittatus australis in the Organ Mountains and T. q. oscuraensis in the Oscura Mountains. We developed a GIS model of potentially suitable habitat based on vegetation and elevation features, evaluated site classifications of the GIS model, and determined vegetation and terrain features associated with chipmunk occurrence. We compared GIS model classifications with actual vegetation and elevation features measured at 37 sites. At 60 sites we measured 18 habitat variables regarding slope, aspect, tree species, shrub species, and ground cover. We used logistic …

Population Structure And Paternity In An American Black Bear (Ursus Americanus) Population Using Microsatellite Dna, Elizabeth A. Sinclair, Hal L. Black, Keith A. Crandall

Western North American Naturalist

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 …

Effects Of Douglas-Fir Beetle (Coleoptera: Scolytidae) Infestations On Forest Overstory And Understory Conditions In Western Wyoming, Joel D. Mcmillin, Kurt K. Allen

Western North American Naturalist

Douglas-fir beetle (Dendroctonus pseudotsugae Hopk.) infestations frequently result from disturbance events that create large volumes of weakened Douglas-fir trees, Pseudotsuga menziesii (Mirb.) Franco. Previous research has focused on determining susceptibility of forest stands to Douglas-fir beetle and predicting the amount of tree mortality from Douglas-fir beetle infestations following disturbance events. Little work has been done on consequent changes in the forest overstory and understory. In the early 1990s, populations of Douglas-fir beetle increased in fire-scorched trees, subsequently infesting undamaged neighboring stands in the Rocky Mountains of western Wyoming, USA. In 1999 transect sampling and 25 pairs of previously infested …

Fire Effects On Spiny Hopsage In South Central Washington, Sally A. Simmons, William H. Rickard

Western North American Naturalist

No abstract provided.

Nest-Site Selection By Western Screech-Owls In The Sonoran Desert, Arizona, Paul C. Hardy, Michael L. Morrison

Western North American Naturalist

No abstract provided.

Discovery Of The Milliped Tylobolus Utahensis Chamberlin In Arizona (Spirobolida : Spirobolidae), Rowland M. Shelley, Lawrence E. Stevens

Western North American Naturalist

No abstract provided.

Index [And Table Of Contents] To Volume 63

Western North American Naturalist

No abstract provided.

Front Matter, Vol. 63 No. 4

Western North American Naturalist

No abstract provided.

End Matter, Vol. 63 No. 4

Western North American Naturalist

No abstract provided.

Full Issue, Vol. 63 No. 4

Western North American Naturalist

No abstract provided.

Aquatic Oligochaeta (Annelida: Lumbriculidae, Haplotaxidae, Naididae, Tubificidae) Of Utah, Douglas R. Spencer, Richard L. Denton

Western North American Naturalist

Thirty-six species of aquatic Oligochaeta (Lumbriculidae, Haplotaxidae, Naididae, Tubificidae) are now known from 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 …

Genetic Analysis Of The Rare Species Salix Arizonica (Salicaceae) And Associated Willows In Arizona And Utah, Julie T. Thompson, Renée Van Buren, Kimball T. Harper

Western North American Naturalist

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 …

Plant Community Patterns In Unburned And Burned Blackbrush (Coleogne Ramosissima Torr.) Shrublands In The Mojave Desert, Matthew L. Brooks, John R. Matchett

Western North American Naturalist

The blackbrush vegetation type is dominated by Coleogyne ramossisima, which is thought to preclude the coexistence of many other plant species. Fire can remove blackbrush cover and possibly increase plant species richness and evenness. Fire also may increase the frequency and cover of alien annual grasses, thereby intensifying landscape flammability. We tested these predictions in unburned and burned (6–14 years postfire) blackbrush at 3 sites spanning the range of this vegetation type in the Mojave Desert.

Species richness in unburned blackbrush was similar to published values for vegetation types in western North America, bur richness varied significantly among the …

Geobotany Of The Niobrara Chalk Barrens In Colorado: A Study Of Edaphic Endemism, Sylvia Kelso, Nathan W. Bower, Kirsten E. Heckmann, Paul M. Beardsley, Darren G. Greve

Western North American Naturalist

The chalk barrens of the Niobrara Formation in the Arkansas River valley of Colorado exhibit a high degree of plant endemism and rarity. We examined their geochemistry and structure as well as the reproductive ecology of their signature species Mirabilis rotundifolius to assess factors influencing endemism. While no single component consistently identified the barren soils, the natural locations that support Mirablilis can be identified using elemental profiles from a cluster analysis of soil extracts. Because seeds germinate and plants proliferate in transplant gardens with non-calcic soils, bedrock and soil chemistry do not appear to be determinant components of endemism. Mirabilis …

Recurrence Of Mexican Long-Tongued Bats (Choeronycteris Mexicana) At Historical Sites In Arizona And New Mexico, Paul M. Cryan, Michael A. Bogan

Western North American Naturalist

The Mexican long-tongued bat (Choeronycteris mexicana) is a nectar-eating species that seasonally inhabits the southwestern United States. Since 1906, fewer than 1500 individuals of C. mexicana have been documented throughout the range of the species. We conducted a field survey in Arizona and New Mexico during summer 1999 to check historically occupied areas for recurrence of C. mexicana. We observed C. mexicana occupying a majority (75%, n = 18) of visited sites. Multiple individuals were observed at many sites, including young-of-year. Choeronycteris mexicana roosted in lighted areas close to entrances within mine adits, abandoned buildings, wide rock …

Distributional Information On Birds From Egg Sets Collected By Henry Rogers Durkee In 1870 In Southwestern Wyoming, Douglas B. Mcnair, James P. Dean

Western North American Naturalist

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 …

Insect-Mediated Pollination In Slickspot Peppergrass, Lepidium Papilliferum L. (Brassicaceae), And Its Implications For Population Viability, Ian C. Robertson, Danielle Klemash

Western North American Naturalist

Field experiments on the pollination biology of slickspot peppergrass, Lepidium papilliferum L. (Brassicaceae), a rare species endemic to microsites in sagebrush-steppe habitat in southwestern Idaho, were conducted at 2 sites from May to July 2001. Site KB contained over 10,000 plants, whereas site WG contained less than 150 plants. Insect exclusion experiments revealed that seed production in L. papilliferum is dependent on insect-mediated pollination; median percent seed set dropped from 70% to 2% when insects were excluded from flowers. A total of 25 insect families from 5 orders visited L. papilliferum flowers: 24 families at KB and 11 families at …

Northern Saw-Whet Owl (Aegolius Acadicus) Migration In The Pacific Northwest, Graham G. Frye, Richard P. Gerhardt

Western North American Naturalist

Northern Saw-whet Owls (Aegolius acadicus) were captured in north central Oregon, USA, during autumn 1999 and 2000 as a pilot study on migration in the Pacific states. We captured 70 individuals, with annual capture rates comparable to those reported for larger studies in the eastern and Midwestern U.S. We investigated differential capture by time of night, time of season, and age. No results were significant due to small samples and brief duration of the study, although some results tended toward significance (P < 0.10). Here we provide a descriptive account of our observations of Northern Saw-whet Owl migration in north central Oregon, the first such study to be presented for the Pacific states.