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1.
Trichophrya sp. (Protozoa) on the gills of cutthroat trout ( Salmo clarki ) and longnose suckers ( Catostomus catostomus ) was studied using light and electron microscopy and tracer techniques. All cutthroat trout, 14 cm in total length and above, from Yellowstone Lake, Yellowstone National Park, Wyoming, were infested with the suctorian. No trichophryans were found on fry or fingerling cutthroat trout. Sixty percent of the examined longnose suckers from the same location were infested. Light microscopy disclosed extensive pathology of gill epithelium in longnose suckers infested with Trichophrya that was not observed for infested cutthroat trout. Electron micrographs show damage to immediate host gill cells by both parasites, depicted by a reduction and lack of mitochondria. Both parasites form attachment helices (0.52 × 0.04 μ m), which may originate in the protozoan cell membrane and function for maintenance of parasite position on the host cell. There was no uptake of 14 C, injected into host fish, via the attachment helices by the parasite that further substantiated the mechanical function for the spiral structure. Protozoan feeding on host tissue may be accomplished by use of necrotic gill tissue and mucus.     相似文献   

2.
We studied nest success, burrow longevity, and rates of burrow reuse for a migratory population of Burrowing Owl ( Athene cunicularia ) in north central Oregon from 1995 to 1997. Nest success varied annually from 50% to 67%. Principal causes of nest failure were desertion (26%) and depredation by badgers ( Taxidea taxus ; 13%). Reuse of available nest and satellite burrows in subsequent years was 87% in 1996 and 57% in 1997. Reuse was highest at burrows in sandy soils, which may indicate that nest-site availability is a limiting factor in sandier soil types. Trampling by livestock resulted in the loss of 24% of all burrows between one season and the next, and natural erosion resulted in closure of 17%. Both causes of burrow failure occurred more frequently in soils with a sand component due to their friable nature. We recommend that habitat used by livestock be evaluated for use by Burrowing Owls, that occupied areas be managed to minimize destruction of burrows by livestock, and that predator-control efforts be revised to exclude mortality of badgers.  相似文献   

3.
Dispersal plays an important role in the population dynamics of many carnivores, yet little information exists about the dispersal and movement patterns of swift foxes ( Vulpes velox ). We radio-collared and monitored 68 swift foxes for dispersal at 2 study sites in northwestern Texas from January 2002 to April 2004. Dispersal distance for juveniles (13.1 ± 0.3 km, s ), adults (10 ± 4.7 km) and transients (25.4 ± 9.1 km) did not differ by age class ( F = 1.49, df = 2, P = 0.24) or sex ( F = 0.23, df = 1, P = 0.63) but differed by study site ( F = 4.72, df = 1, P = 0.04). Mean dispersal distance from private ranches (PR) was greater than from National Grasslands (NG). Peak dispersal occurred during October– November (13 individuals) and January–February (7 individuals). Dispersal direction was influenced by land-use practices (i.e., toward rangelands and away from anthropogenic features). Direction of dispersal among foxes that occupied the NG was uniform ( n = 16, P = 0.08), whereas foxes from PR dispersed in a northwesterly direction ( n = 18, P ≤ 0.001) away from a town and croplands. Three resident adult foxes made extraterritorial movements. Distances of these movements ranged from 0.2 km to 11.4 km. Distance of extraterritorial movements did not differ by sex ( F = 0.05, P = 0.83), nor by duration of movement ( F = 1.11, P = 0.32). Knowledge of movement distances and patterns is important for conservation and protection of swift foxes and their habitats.  相似文献   

4.
We examined winter nutritional quality of current-year bud and stem tissues from burned and unburned stands of Gambel oak ( Quercus gambelii Nutt.). Nutritional analyses were based on the amount of forage consumed by wintering mule deer. Deer use along the Utah Valley foothills averaged 6.25-10.7 cm of current-year growth. Of the tissues examined, post-fire bud tissue had the highest nutrient content, with a mean of 9.51% crude protein, 0.19% phosphorus, and 34.0% in vitro digestibility. Composite values (bud + stem) for unburned stands were slightly higher in crude protein and phosphorus and lower in digestibility than those reported in previous studies. Nutrient values from burned stands were significantly higher than those of unburned stands for all three measures. Tannin content of the burned-area regrowth was also higher. Overall forage value of Gambel oak to wintering mule deer is relatively low.  相似文献   

5.
We report the discovery of established populations of Cnemidophorus neomexicanus in the Salt Lake City area. These are the 1st records of this species in Utah and in the Great Basin and are far from all other known populations of the species. We conclude that C. neomexicanus was introduced in the Salt Lake City area, perhaps within the last 30 years.  相似文献   

6.
We examined abundance and flight periodicity of 3 predators of bark beetles (Coleoptera: Curculionidae, Scolytinae), Temnochila chlorodia (Mannerheim) (Coleoptera: Trogositidae), Enoclerus sphegeus (Fabricius) (Coleoptera: Cleridae), and E. lecontei (Wolcott) (Coleoptera: Cleridae), across an elevational gradient of ponderosa pine ( Pinus ponderosa Lawson) forests in north central Arizona. Predator populations were estimated at 10 sites in each of 3 elevation bands (low: 1600–1736 m; mid: 2058–2230 m; high: 2505–2651 m) for 3 years (2004–2006) using pheromone-baited funnel traps targeting 3 primary bark beetle species. We also investigated how predator abundance and flight seasonality related to those of 5 bark beetle species: Ips pini (Say), I. lecontei Swaine, Dendroctonus frontalis Zimmermann, D. brevicomis LeConte, and D. adjunctus Blandford. Temnochila chlorodia was most abundant in the low- and mid-elevation bands, whereas E. sphegeus was most abundant in the high-elevation band. Enoclerus lecontei showed no consistent elevational trend in abundance. Within each elevation band, changes in annual abundance of pooled predator species tracked shifts in abundance of pooled bark beetle species. In general, predator flight initiation coincided with or closely followed bark beetle flight initiation in the spring, but predator flight terminated before flight activity ended for most bark beetle species in the fall. In addition, the ratio of prey to predators was lowest in the summer and highest in the fall. This suggests that all bark beetle species examined may be provided temporal escape from their predators in the fall. For all 3 predator species, the pheromone-baited trap targeting D. brevicomis was less attractive than the pheromone-baited traps targeting I. pini and I. lecontei.  相似文献   

7.
Genetic variation within populations reflects population-level social and demographic processes and influences how a population behaves as an evolutionary unit. We examined partitioning of genetic variation in striped skunks ( Mephitis mephitis ) from the Southern High Plains of Texas during 1994-1995. Sixty-nine male and 35 female skunks were sampled on four 12.8-km 2 study plots. Plot centers ranged from 17.6 to 61.6 km apart. We used multi-locus DNA fingerprinting with 2 probes, pV47 and CTTxAGG, to test 3 hypotheses: (1) females are more genetically similar to other females than males are to other males on the same plot (indicating greater female philopatry than male philopatry), (2) genetic similarity is greater within plots than among plots (indicating partitioning of genetic variation in space), and (3) genetic similarity of males decreases as the distance separating males increases (indicating geographic distance affects rates of gene flow). In general, males on a plot had lower average genetic similarity than females. Genetic similarity within plots was not different from genetic similarity among plots for males or for females. Genetic similarity of males did not decrease with increasing distance among plots. The lack of geographical genetic structure in striped skunks suggests at the scale of this study (< 60 km) that gene flow of biparentally inherited genes is not distance-mediated. However, the higher similarity values for females than for males on the same plot supports an effect of male-biased dispersal and female philopatry on partitioning of genetic variation between sexes.  相似文献   

8.
Nineteen study sites were established in areas infested with saltcedar bordering Utah Lake in central Utah. Saltcedar cover on the sites averaged 57&#37; but varied widely from community to community. Seventeen soil factors were measured relative to the stands studied. Cover of saltcedar was regressed against the different soil factors, but no patterns were detected. Saltcedar functioned equally well at all levels of each gradient studied and appeared able to accommodate wide variations in all factors studied. It is suggested that saltcedar has evolved a general-purpose genotype that contributes to its being a vigorous and troublesome weed. Criteria as to why it is such an aggressive weed are listed.  相似文献   

9.
The mountains of north central Washington contain a variety of habitat types, from shrubsteppe to high alpine meadows. While native bee surveys of some surrounding areas like the Columbia Basin are fairly complete, little work has been done in the mountains of north central Washington to document the diversity of bees found therein. We conducted a survey of native bees in the Tonasket Ranger District of the Okanogan-Wenatchee National Forest during summer 2004. Collections yielded a diverse bee fauna (140 species in 24 genera) visiting diverse floral elements (57 plant species in 18 families). These preliminary data suggest that a rich bee fauna exists in the Okanogan Basin and surrounding mountains.  相似文献   

10.
11.
The freshwater and estuarine catfishes of central Sumatra draining to the Indian Ocean and between the Rokan and Batang Hari drainages are reported on the basis of literature records, museum material, and recent collections. Eighty-two species in 10 families are recorded from central Sumatra. Hemibagrus velox and Nanobagrus stellatus are described here as new species. Akysis macronema and Clarias olivaceus are redescribed here.  相似文献   

12.
Productivity and food habits of the Barn Owl ( Tyto alba ) utilizing nest boxes in Juab, Utah, and Salt Lake counties, Utah, During 1979-1984 were examined. Average clutch size was 5.8 eggs for the 6-yr period; mean number fledged was 3.9 young per successful nest. While severe weather during the 1981-82 winter did not result in significant decrease in productivity during the 1982 breeding season, it may have resulted in a significant overproduction of female young. Barn Owls in north central Utah fed almost exclusively on mammalian species, particularly Microtus spp. Difference in clutch size between areas and years may be a response to availability as well as abundance of prey.  相似文献   

13.
The European ground squirrel (Spermophilus citellus) is a small rodent categorized as vulnerable (IUCN). To investigate the parasitic fauna of this species in Greece, faecal samples from 125 animals belonging to six different populations were examined by standard parasitological methods. Parasites were found in 118 of the animals (94.4%). Oocysts of the coccidia Eimeria callospermophili were found in 92 animals (73.6%), Eimeria citelli in 76 (60.8%), Eimeria cynomysis in 41 (32.8%), Eimeria spp. (17.6%), Cryptosporidium spp. in 29 (23.2%), cysts of Entamoeba spp. in 32 animals (25.6%) and eggs of the trematode Brachylaima spp. in seven animals (5.6%). This is the first report of Entamoeba spp., Cryptosporidium spp. and Brachylaima spp. in S. citellus. The possible impact of these findings on the health status of S. citellus and the possible significance to domestic animals or public health is discussed.  相似文献   

14.
Ten plant communities containing bitter nightshade ( Solanum dulcamara ) were studied and the ecology and naturalizing relationships of bitter nightshade in central Utah area were investigated. Biotic and abiotic factors from each area were statistically analyzed. The data indicated that bitter nightshade was negatively correlated (P &nbsp;  相似文献   

15.
Yellow starthistle ( Centaurea solstitialis ) is native to Europe and Asia and has quickly invaded disturbed grasslands and rangelands in the western United States. The purpose of our study was to determine the effects of starthistle on rodents at Beale Air Force Base, Yuba County, California, by examining rodent species diversity, species abundance, age structure, and reproductive condition among locations with low, medium, and high percent cover and height of starthistle. Listed in decreasing order of abundance, the rodents were house mouse ( Mus musculus ), California vole ( Microtus californicus ), deer mouse ( Peromyscus maniculatus ), western harvest mouse ( Reithrodontomys megalotis ), and roof rat ( Rattus rattus ). Indices of diversity did not differ among starthistle cover categories. Regression analyses showed that Reithrodontomys megalotis was more abundant in high-cover starthistle plots, with 90.5% of captures occurring in at least 40% starthistle cover. Significant differences were found in capture rates, reproduction, and age between season only. To manage for all rodent species, an area with medium percent cover and height of starthistle will likely provide adequate protective cover.  相似文献   

16.
A new ostracod genus and species, Namiotkocypria haysensis gen. et sp. nov., of the subfamily Cyclocypridinae is reported from an artesian well in San Marcos, Texas, USA. The new genus has several unique characteristics that distinguish it from all other genera in the subfamily, including postero-dorsally inclined valves, absence of tubercles in marginal zones of the valves, very short swimming setae on A2, length of aesthetasc ya on A1, asymmetric clasping organs, and differences in the shape of the hemipenis and other cheatotaxial parts. A detailed comparison among related genera of the subfamily is provided.

www.zoobank.org/urn:lsid:zoobank.org:pub:42FF41E3-E2FB-4BB6-B9F0-948ED0A0807A.  相似文献   


17.
Extensive Engelmann spruce ( Picea engelmannii Parry ex Engelm.) mortality caused by the spruce beetle ( Dendroctonus rufipennis Kirby) has been occurring at the southern end of the Wasatch Plateau in central Utah. This spruce beetle outbreak is the largest recorded in Utah history. An extensive ground survey was conducted in 1996 on the Manti-LaSal National Forest, Sanpete and Ferron Ranger Districts, to document mortality and impact of a major spruce beetle outbreak on post-outbreak forest composition. In 1998 the same sites were resurveyed. Survey results indicate Engelmann spruce basal area (BA) loss averaged 78% in trees ≥5 inches diameter breast height (DBH) in 1996. Ninety percent of BA ≥5 inches DBH was lost within the same sites by 1998. Tree mortality of spruce ≥5 inches DBH expressed in trees per acre (TPA) averaged 53% in 1996. In 1998 TPA ≥5 inches DBH mortality averaged 73%. Before the outbreak live Engelmann spruce BA ≥5 inches DBH averaged 99 square feet, and TPA ≥5 inches DBH averaged 97. In the sites surveyed in 1996 and resurveyed in 1998, Engelmann spruce BA ≥5 inches DBH averaged 21 and 9 square feet, and TPA ≥5 inches DBH averaged 43 and 25, respectively. Overstory tree species composition changed from stands dominated by spruce to subalpine fir. Stand ratings for potential spruce beetle outbreaks were high to mostly medium hazard pre-outbreak and medium to primarily low hazard by 1998, as a result of reduction in average spruce diameter, total basal area, and overstory spruce.  相似文献   

18.
19.
Virgoiulus minutus (Brandt 1841) (Julida: Blaniulidae), the only indigenous representative of the family in the New World, occurs, or can be expected, in parts or all of 24 states east of the Central Plains plus the District of Columbia; it is documented for the 1st time from Mississippi, Oklahoma, and Texas. The northern-, southern-, and westernmost localities are in Berrien County, Michigan; Putnam County, Florida; and Angelina/Rusk Counties, Texas, respectively. New England, Utah, Wyoming, Canada, and Mexico are deleted from the range, and specific localities are reported to augment previous generalized citations; those from Mexico represent misidentifications of Nopoiulus kochii (Gervais, 1847), an introduced European species that is recorded from Mexico City, Distrito Federal. Records of V. minutus from Pennsylvania, Virginia, South Carolina, Georgia, Alabama, West Virginia, Ohio, Illinois, Michigan, and Missouri are the 1st definite localities from these states; a sample from ""Anechar,"" believed to be a misspelling of ""Arrochar,"" a neighborhood in Staten Island, is considered the 1st definite record from New York. The published statement of occurrence in Delaware in general is the only known record of an indigenous diplopod from this state.  相似文献   

20.
Eight study sites were examined in Strawberry Valley, Utah, to assess the response of aspen ( Populus tremuloides Michx.) to cutting activities of beaver ( Castor Canadensis Warren & Hall) and to determine patterns by which the animals utilize aspen stands. Sites utilized by beaver, along with adjacent control plots in mature, uncut aspen stands, were sampled. Age-class profiles of control plots were composed of a broad age distribution with trees ranging from 3 to 108 years old. Age-class profiles for aspen sprouts in areas previously used by beavers were composed of trees averaging seven years of age with a range of 1 to 24 years. Age distribution of sprouts in areas used by beaver show a tendency to be skewed toward younger age classes. Average density of aspen in areas used by beaver was 15,800stems per hectare compared to 2,980 stems per hectare in controls. Stump densities in use areas ranged from 900 to 5,066 stems per hectare. Densities of stumps in the 0-5-cm size class were greater in areas used by beavers than in the corresponding size class in the mature forests. A regression equation describing age versus diameter relationships was calculated using data from 312 aspen trees. Total phenolics and mineral nutrients in the twigs and bark of mature aspen trees and aspen sprouts were also examined to determine if variations could explain foraging patterns of beaver in the valley. Total phenolics were highly variable between sampling groups, and differences were not significant. Twigs from mature aspen and aspen sprouts were significantly higher in nitrogen, phosphorus, and iron. Zinc was significantly higher in the bark of mature aspen trees and twigs of aspen sprouts. Calcium concentrations were significantly higher in mature aspen bark, and magnesium was significantly higher in mature aspen twigs.  相似文献   

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