Fecal pellets of American pikas ( Ochotona princeps ) provide a crude chronometer for dating patch occupancy

American pikas ( Ochotona princeps ) seem to be especially vulnerable to climate change, with recent extinctions of pika populations being attributed to global warming. Incomplete historical location records are currently used to examine changes in pika distributions. A method of determining recent pika distributions in the absence of historical records is needed. Here I report on changes over time of known-age pika fecal pellets up to 36 years old. Predictable changes in diameter, internal consistency, and color of pellets provide a method to approximate the dates of last occupation in patches where pikas have been extirpated. La pika Americana ( Ochotona princeps ) parece ser especialmente vulnerable al cambio climático, al que se atribuyen extinciones recientes de sus poblaciones. Actualmente, se están utilizando los registros históricos incompletos de ubicación para examinar cambios en las distribuciones de pikas. Es necesario un método para determinar distribuciones recientes de pikas a falta de registros históricos. Reporto aquí los cambios que se han observado con el transcurso del tiempo en bolitas fecales de hasta 36 años de antigüedad. Cambios predecibles en diámetro, consistencia interna y color de las bolitas proporcionan un método para datar aproximadamente cuánto hace que vivían pikas en sitios de los que han sido extirpadas.     

Interpopulational variation of blood proteins in pika ( Ochotona princeps saxatilis )

Studies were undertaken to examine the degree of divergence in four populations of pika in Colorado. Separation of blood proteins was accomplished utilizing acrylamide - gel disc electrophoresis. Separate analyses of variance were carried out for the relative mobilities of two of the transferrins (designated RM β 1 and RM β 2 ), the mean relative distance difference of the two transferrins (DM), and the density of the most prominent albumin ( α 1 ) and transferrin ( β 2 ) bands. Although the four populations were characterized by a general similarity of the gel patterns, both interpopulational and sexual variations were observed. Variations between the sexes had to do with the amounts of protein, not with differences in protein mobility. The only significant populational differences were found in reference to density and DM. The interpopulational differences may serve as an indicator of populational divergence that has not been indicated by standard morphological characters. The significant patterns of variation observed in the blood proteins of the four populations studied may reflect a lack of gene now between isolated populations.     

American Pikas ( Ochotona princeps ) in northwestern Nevada: a newly discovered population at a low-elevation site

The central tenet of island biogeography theory—that species assemblages on islands are functions of island area, isolation from mainlands, and vicariance—has been altered by the demonstrable effects that rapid climate change is imposing on insular faunas, at least in isolated mountaintops. Although populations of American pikas ( Ochotona princeps ) continue to suffer extirpations, and although the lower bounds of the pika's elevational distribution are shifting upslope across the Great Basin, we report here on the new discovery of a low-elevation population of pikas in a mountain range from which they had not been reported previously. This discovery, particularly in the context of relatively rapid ecological change, highlights the importance of seeking out original sources of information and performing spatially extensive fieldwork. Results presented here further illustrate that although thermal influences appear to be the single strongest determinant of pika distribution currently, such influences interact with a number of other factors to determine persistence.     

Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon

The chronology of Juniperus occidentalis (western juniper) expansion in eastern Oregon, the effect of plant canopy and interspace on J. occidentalis seedling establishment and growth rates, and the age of J. occidentalis maximum reproductive potential were determined. Measurements were recorded in twenty-two 0.4-ha plots established in sagebrush-grassland communities and six 0.1-ha plots in Populus tremuloides (quaking aspen) communities. J. occidentalis began increasing during the 1880s in stands containing > 130 yr old. Relatively steady establishment ensued into the 1950s and then began to progress at a geometric rate in the 19602. J. occidentalis encroachment into aspen stands began between 1910 and 1920. The largest proportion of juvenile trees established beneath Artemisia species in sagebrush-grassland communities. J. occidentalis trees appeared to reach full reproductive potential at > 50 yr of age. The ratio of male:female trees increased from 1.7 in scattered J. occidentalis stands to 3.8 in closed stands. The initiation of J. occidentalis encroachment during the late 1800s coincides with optimal climatic conditions for Juniperus berry production and establishment, reduced fire-return intervals, and heavy livestock grazing. The accelerated increase in J. occidentalis expansion since 1960 may be due to the continued absence of fire, abundant woody plant cover, and the large increase in J. occidentalis seed production.     

Winter-active wolf spiders (Araneae: Lycosidae) in thermal habitats from western Romania

Shores of channels with thermal water provide an adequate microclimate for maintaining wolf spiders in activity during winter. Of the spiders collected after the winter survey of 22 thermal habitats from western Romania, 93.02% were juveniles and subadults, while the remaining individuals belonged to the following seven species: Arctosa leopardus, Pardosa amentata, Pardosa proxima, Pirata piraticus, Piratula latitans, Trochosa robusta and Trochosa ruricola. The reproductive period of some species is altered under the influence of neighbouring hot waters, as revealed by the capture of females with egg sacs and spiderlings, during winter.     

Juniperus occidentalis (western juniper) establishment history on two minimally disturbed research natural areas in central Oregon

While a trend toward western juniper ( Juniperus occidentalis spp. occidentalis ) super-dominance in big sagebrush ( Artemisia tridentata ) communities of the Pacific Northwest since the late 1800s has been well documented, establishment dates of western juniper in less disturbed environments have not. In this paper we document the establishment history of western juniper on 2 minimally disturbed research natural areas that have substantial differences in their physical characteristics. On each site we randomly established twenty 0.05-ha plots to obtain per hectare counts of mature and juvenile western juniper and to obtain a sample of 100 trees closest to the plot center. These trees were then dated using standard dendrochronological techniques. The lower-elevation, more xeric site has an establishment history that suggests it is an emerging western juniper woodland, with the majority of trees sampled establishing since 1978. The higher-elevation site is an older, well-established woodland with a more even temporal distribution of trees. These results suggest that suitable establishment sites may switch from canopy dependence in emerging woodlands to open sites in mature woodlands and that neither domestic livestock grazing nor active fire suppression is a required mechanism for establishment.     

Temporal variation in the diets of California Quail in western Oregon

This study was designed to describe dietary changes by comparison of information on long-term diet and plant food availability of California Quail ( Callipepla californica ) in western Oregon. We examined crops from 222 California Quail collected in 1976-78 and 1985-87. Diets included 14 key plant foods (annual frequency > 15%) among 53 taxa consumed; 10 of the 14 key foods were similar between time periods. Collectively, key foods contributed 87% of the diet by aggregate dry mass during 1985-87; six species of legumes (family Leguminosae) composed 67% of diet. Relative rankings of availabilities of key foods were similar between 1976-78 and 1985-87. This study revealed that quail were opportunistic within the group of key foods because 9 of the 14 key foods were consumed in different frequencies between the two periods. Legumes were an important dietary component in western Oregon because they composed the bulk of the diet, were among the most frequently consumed, and most were taken in substantially greater proportions than available.     

Home range of the western jumping mouse, Zapus princeps, in the Colorado Rocky Mountains

Western jumping mice, Zapus princeps, were live - trapped during the summer of 1975 in an aspen forest in the Front Range of the Colorado Rocky Mountains. Home range sizes were calculated using the exclusive boundary strip method, and it was discovered that males had larger home ranges (298 – 3315 m 2 , x = 1743 m 2 ) than females (680 – 1275 m 2 , x = 1041 m 2 ). Mean range length was 96.5 m for males and 78.5 m for females. Spatial relationships showed that females tended to be more territorial than males, based on the females' higher percentage of exclusive home ranges, greater distance between centers of activity, and more uniform spacing.     

Mites (excluding chiggers) of mammals of Oregon

New information on the ectoparasitic mites of the following species of mammals from Oregon is presented: (1) pika — Ochotona ; (2) squirrels — Eutamias, Spermophilus, Tamiasciurus; (3) grasshopper mouse — Onychomys; (4) woodrats — Neotoma; (5) muskrat — Ondatra; (6) jumping mice — Zapus; and (7) weasels — Mustela, Spilogale. New records of species for the state and new host records are also given. Finally, a cross - referenced list of all known mites of wild mammals from Oregon is presented.      

Summer habitat use and selection by female Sage Grouse ( Centrocercus urophasianus ) in Oregon

Cover types and vegetative characteristics (e.g., grasses, forbs, shrubs) used by female Sage Grouse ( Centrocercus urophasianus ) during summer were compared with available habitat on two study areas in southeastern Oregon. Broodless hens, which constituted 114 of the 125 (91%) radio-marked hens studied, selected big ( Artemisia tridentata ) subspp.) and low sagebrush ( A. arbuscular ) cover types at both study areas. At Hart Mountain, broodless hens did not select specific vegetative characteristics within cover types. However, at Jackass Creek, forb cover was greater ( P = .004) at broodless hen sites than at random locations. Differences in habitat use by broodless hens between study areas were associated with differences in forb availability. Broodless hens used a greater diversity of cover types than hens with broods. Broodless hens gathered in flocks and remained separate from but near hens with broods during early summer. By early July broodless hens moved to meadows while hens with broods remained in upland habitats.     

Habitat and distribution of pygmy rabbits ( Sylvilagus idahoensis ) in Oregon

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* 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;} An investigation to determine the location and extent of populations of pygmy rabbits ( Sylvilagus idahoensis ) in Oregon, and to describe several biotic and physical components within communities that include pygmy rabbits, was conducted from October 1981 to September 1983. Of 211 sites suspected of supporting the species based on interpretation of museum records, aerial photographs, soil maps, and interviews with biologists and area residents, 51 exhibited evidence of being inhabited when examined in summer 1982. Soil and vegetation components were sampled at 15 sites occupied by pygmy rabbits and 21 sites adjacent thereto. At inhabited sites, mean soil depth (51.0 ± 2.3 cm), mean soil strength of surface (0.8 ± 0.2 kg/cm 2 ) and subsurface (3.8 ± 0.3 kg/cm 2 ) horizons, shrub height (84.4 ± 5.8 cm), and shrub cover (28.8 ± 1.4%) were significantly greater ( P 2 ), density of forbs (3.4 ± 0.6/1,000 cm 2 ), and cryptogam cover (2.4 ± 0.5%) were not. Except for the clay component of subsurface soils, texture of surface and subsurface soils were not significantly different between sites occupied by pygmy rabbits and adjacent sites. The affinity of pygmy rabbits for areas with greater shrub cover, shrub height, soil strength, and soil depth, and, to a small degree, coarser soil texture possibly was related to availability of forage, security from predation, and ease of burrow construction. Analysis of 472 samples of sagebrush ( Artemisia tridentata ) collected at and near sites inhabited by pygmy rabbits indicated their distribution was not dependent upon the presence of specific subspecies of sagebrush. A marked decrese in evidence of occupancy of sample sites and of pygmy rabbit activity at occupied sites in 1983 indicated that populations of pygmy rabbits were susceptible to rapid declines and possible local extirpation. Fragmentation of sagebrush communities poses a potential threat to populations of pygmy rabbits, but the severity of the threat presently is unknown.     

Microhabitat partitioning by two chipmunk species ( Tamias ) in western Colorado

We examined microhabitat use of sympatrically occurring Tamias minimus (least chipmunk) and T. rufus (Hopi chipmunk) in a pi?on-juniper/sagebrush vegetative community near Molina, western Colorado, from October 1994 to June 1999. This community is dominated by 2 major microhabitat types: shrub (sage; Artemisia spp.) and tree (pine and juniper; Pinus edulis and Juniperus scopulorum ). Small mammals were live-trapped, marked, and released throughout this study. When it was the most abundant Tamias species on the study plots (1994-1997), Tamias minimus captures were associated with trees. Tamias rufus also exhibited this association but was captured at very low abundances during this period. Tamias rufus abundance was much greater, on average, than that of T. minimus between 1998 and 1999. During this time T. minimus captures were not associated with trees, but T. rufus captures remained associated with trees. As has been previously reported for other Tamias species, the greater abundance of 1 of 2 coexisting congeners in select areas may play a role in the microhabitat use of these 2 chipmunk species.     

Springtime movements, boost Use, and foraging activity of Townsend's big-eared bat ( Plecotus townsendii ) in central Oregon

Seasonal movements, roost-site fidelity, and foraging activity patterns are largely unknown for western populations of Townsend's big-eared bat ( Plecotus townsendii ). We used miniature radiotelemetry units to track springtime movements of six bats inhabiting forested lava flows in central Oregon, and found that bats moved up to 24 km from hibernacula to foraging areas. Individual bats returned to the same foraging area on successive nights but shifted to different areas in presumed response to changes in insect availability. Both sexes apparently use a series of interim roost sites between emergence from hibernation and the time females enter into maternity colonies, with little individual fidelity to these sites. In regions characterized by extensive lava-flow topography, suitable daytime roosts are numerous and dispersed over a large area, allowing bats to move relatively great distances to locate foraging ranges. Hence, the actual area of concern for effective management of individual populations can be considerably larger than indicated solely by locations of hibernacula and maternity caves of this declining species.     

Mushroom consumption (mycophagy) by North American cervids

Native mushrooms play an important, though often underestimated, role in deer, elk, and caribou diets in North America. Mushrooms are often noted as an unusual or anomalous food in the diets of cervids; yet they often dominate diets in the late summer and fall in forested areas of western North America and throughout the year in the southeastern U.S. Mushrooms are particularly high in protein (16-19%), phosphorus (average 0.75%), and potassium (average 2%). Also, mushroom production is generally greatest in fall. Therefore, they are a highly nutritious food in late season when other native forages may marginally meet basal nutrient requirements of ungulates.     

Post-breeding season movements of Columbia spotted frogs ( Rana luteiventris ) in northeastern Oregon

Movements of Columbia spotted frogs ( Rana luteiventris ) were determined after breeding to provide managers with information on habitat requirements. We radio-tagged 47 adults and observed movements occurring with 22 frogs. Eleven frogs remained in breeding ponds, and 11 moved to other ponds or river stretches during spring and summer 1998. Distances frogs traveled to other water bodies ranged from 15 to 560 m. Movements appeared to be influenced by availability of habitat and aquatic conditions. Eleven of 16 frogs located within 100 m of other permanent water sources moved, while no frogs at an isolated breeding pond moved. Frogs moved to river stretches in July where water temperatures averaged 5.6 ° C cooler than ponds. Knowledge of Columbia spotted frog movements and habitat use in summer enables land managers to make decisions on activities that affect aquatic sites, vegetation, and stream structures that may influence frog populations.     

List of Oregon Scolytidae (Coleoptera) and notes on new records

Listed are 121 species of Scolytidae from Oregon. Ten species are reported from Oregon for the first time: Hylastes tenuis Eichhoff, Phloeosinus scopulorum scopulorum Swaine, Phloeosinus hoferi Blackman, Trypodendron betulae Swaine, Xyleborus xylographus (Say), Trypophloeus striatulus (Mannerheim), T. Thatcheri Wood, Procryphalus mucronatus (LeConte), Pityophthorus scalptor Blackman, and Monarthrum dentigerum (LeConte). The second Oregon specimen of an exotic species, Xyleborus californicus Wood, is reported also.     

First record of the spotted bat ( Euderma maculatum ) from Oregon

A spotted bat ( Euderma maculatum ) was taken at Mickey Springs, 28 km northeast of Andrews, Harney County, Oregon. This represents a 225 km range extension and a new record for Oregon.     

Role of three rodents in forest nitrogen fixation in western Oregon: another aspect of mammal-mycorrhizal fungus-tree mutualism

To determine the role of the California red-backed vole ( Clethrionomys califonicus ), the northern flying squirrel ( Glaucomys sabrinus ), and the deer mouse ( Peromyscus maniculatus ) in the nitrogen cycle of forest stands in western Oregon, bacterial colonies were isolated and purified from feces, and their nitrogen-fixing ability measured by acetylene-reduction assay. The ability of the bacterial species Azospirillum   sp. to withstand freezing was also tested. Fecal extracts were used to test whether fecal pellets can provide the nutrients necessary for growth of the bacteria. All the feces tested contained viable nitrogen-fixing bacteria, and both species can survive drying and one can survive freezing. Azospirillum colonies grew well on liquid medium but required yeast extract for growth and nitrogenase activity. Fecal extracts from flying squirrels and chickarees ( Tamiasciurus douglasi ) were as effective as the yeast. The results suggest another link in the chain of mutualism that unites small mammals, mycorrhizal fungi, and forest trees.     

Dispersal of sagebrush-steppe seeds by the western harvester ant ( Pogonomyrmex occidentalis )

Like many seed-harvesting ants, the western harvester ant ( Pogonomyrmex occidentalis ) can act as both a predator and a seed disperser. Dispersal results when seeds are dropped en route to the nest, are left in nest granaries when colonies die or are abandoned, or are removed from granaries and discarded in nest middens. This study examined the density and species identity of seeds discarded in harvester ant nest middens and compared them with those found in nearby soils. Nineteen species of seeds were recovered from middens, compared with 13 species in 5-m reference areas and 9 species in adjacent disk areas. Total density of sound seeds was nearly 3 times higher in middens than at 5 m from the nest and nearly 50 times higher than in disk soils. Moreover, 4 of the 6 most common species overall were significantly more abundant in middens. One species, Munro globemallow ( Sphaeralcea munroana ), was recovered from nearly 50% of middens but was not found in the other 2 areas. These findings suggest that the western harvester ant is a potentially important disperser of some sagebrush-steppe plant species.     

Ecology of Comandra umbellata (Santalaceae) in western Wyoming

Comandra umbellate is the alternate host of a hard pine canker rust disease induced by the fungus Cronartium comandrae . The occurrence and density of C. umbellata were recorded near lodgepole pine stands in the Wind River District, Shoshone National Forest, Wyoming. Comandra populations occurred most often on slopes with southern aspects, particularly southwestern, and on steep slopes; these sites tended to be dry and relatively open. Comandra was also found growing under heavy perennial shrub canopy covers. It was most often associated with sagebrush but was common near other perennial shrubs as well. Overall, C. umbellata appeared to be a poor competitor with dense grass populations. Comandra was found primarily on Abies lasiocarpa/Juniperus communis, Pinusflexilis/ Hesperochloa kingii , and Artemisia tridentata/Festuca idahoensis habitats. No comandra was found in the Abies lasiocarpa/Vaccinium scoporium habitat.