Status and life history notes on the native fishes of the Alvord Basin, Oregon and Nevada

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;} Three fishes, two species of Gila, and an undescribed subspecies of cutthroat trout, are endemic to the Alvord Basin. Historically, the Alvord cutthroat trout, Salmo clarki ssp., inhabited the larger creeks of the basin but has been extirpated in pure form because of introgression with introduced rainbow trout, Salmo gairdneri. Gila boraxobius is restricted to the thermal waters of Borax Lake and its outflows in the northern part of the basin. This species is endangered because of alteration of its fragile habitat. The Alvord chub, G. alvordensis, is recorded from 16 localities throughout the basin, including springs, creeks, and reservoirs. Although G. alvordensis as a species is not in jeopardy, many populations are small and could be easily eliminated by habitat destruction or by the introduction of exotic fishes. Competition with exotic guppies, Poecilia reticulata, has extirpated the Thousand Creek Spring population of Alvord chubs. Both species of Gila are opportunistic omnivores, consuming primarily chironomids, microcrustaceans, and diatoms. The Borax Lake chub also consumed large numbers of terrestrial insects, but specialized feeding on molluscs was noted in the West Spring population of Alvord chubs. Borax Lake chubs spawn throughout the year; however, most spawning occurs in early spring. Borax Lake chubs mature at a small size, occasionally less than 30 mm standard length, and seldom live more than one year. Alvord chubs are typically much larger than the Borax Lake species and live at least into their fifth year.     

Conservation status of the threatened, insular San Jose brush rabbit ( Sylvilagus mansuetus )

The conservation status and distribution of the insular endemic San Jose brush rabbit ( Sylvilagus mansuetus ), as well as threats to its population viability, were determined through surveys undertaken since 1995 on San José Island in the Gulf of California, Mexico. Sylvilagus mansuetus is restricted to a specific desert habitat found in the southwestern coastal plains of the island. Vegetation in this habitat is composed primarily of 7 plant species. The extent of rabbit occurrence is only 20 km 2 , and the population density estimate in the most optimal habitat is 25–35 individuals · km –2 . To our knowledge, the San Jose brush rabbit possesses the smallest distribution among all lagomorph species. Sylvilagus mansuetus is threatened by a population of feral cats and by human activities, including illegal hunting, development of a tourist area, and a salt mine. Human activities, even over a short time frame, could severely impact this restricted area and endanger the survival of this species. Recommended management includes removing cats and conducting additional research on the rabbit’s life history and ecology. Se determinó el estado de conservación y la distribución del conejo de San José ( Sylvilagus mansuetus ), una especie insular endémica, mediante muestreos que se han llevado a cabo desde 1995 en la isla de San José en el Mar de Cortés, México. Sylvilagus mansuetus quedó restringido a un tipo específico de hábitat desértico en la llanura costera suroccidental de la isla, donde predominan 7 especies de plantas. La extensión de la especie es de sólo 20 km 2 , y la densidad de la población en el hábitat óptimo se estimó entre 25 y 35 individuos · km –2 . Hasta donde conocemos, el conejo de San José tiene el área de distribución más pequeña de todas las especies de lagomorfos. Sylvilagus mansuetus se ve amenazado por una población de gatos ferales y por actividades humanas tales como la caza ilegal, el turismo y la operación de una mina de sal. Las actividades humanas podrían tener un impacto severo en esta área restringida y podrían poner en peligro la supervivencia de esta especie dentro de poco tiempo. Algunas acciones recomendables para el manejo de la especie incluyen el eliminar los gatos y llevar a cabo estudios adicionales para obtener más detalles sobre la biología y ecología del conejo a fin de mejorar su conservación.     

Diatoms of Oregon Caves National Monument, Oregon

The diatom flora of the Oregon Caves National Monument, Josephine Co., Oregon, was investigated. Diatoms were distributed throughout the cave system with abundance and species diversity depending upon moisture, light, availability of mineral nutrients, and proximity to cave openings. Twenty-six taxa were identified and described.     

Summary atlas of deep-living demersal fishes in the North Atlantic Basin

Data from 9 major trawling surveys made around the North Atlantic Basin at slope, rise and abyssal depths provide directly comparable information on deep demersal fish distribution and faunal composition. 338 species in 57 families and 189 genera are recorded, and semi-diagrammatic maps showing relative abundance both horizontally and vertically for 67 of these are presented. Alepocephalidae, Gadidae, Macrouridae, Moridae and Ophidiidae comprise nearly 2/3 of all species taken. 296 species were taken at slope depths (200–2250 m), 99 at rise depths (2250–4500 m), and 32 at abyssal depths (>4500 m). Diversity and the rate of endemism were highest on the slope. The Norwegian, Caribbean and Mediterranean Basins appear to harbor impoverished versions of the adjacent Atlantic Basin fauna. Each species distribution appeared to be rather exceptional and no repeatable pattern could be found amongst the maps.     

Shrew and heteromyid records from the Great Basin of Oregon and Utah

Oregon records from Harney County establish a minimum altitudinal occurrence for the water shrew ( Sorex palustris ), identify an isolated population of the montane shrew ( Sorex monticola obscures ), and provide an additional specimen of Merriam's shrew ( Sorex merriami ). Utah records extending the ranges in the southeastern part of the Bonneville Basin for the little pocket mouse ( Perognathus longimembris ), long-tailed pocket mouse ( Perognathus formosus ), and dark kangaroo mouse ( Microdipodops megacephalus ) are also given.     

Diets of nesting Northern Goshawks in the Warner Mountains, California

Diets of Northern Goshawks ( Accipiter gentilis ) in western and eastern North America show regional differences. This variation may be explained by the opportunistic feeding behavior of Northern Goshawks and the greater number of potential prey species in western North America. We predicted that a population of Northern Goshawks in the Warner Mountains of California would take significantly more mammals than birds as prey. Goshawk diet in the Warner Mountains was determined by pellet analysis and prey remains. A total of 33 samples from 23 nest sites was collected and analyzed. Diets were quantified by determining the minimum number of individuals per sample at each nest site. As predicted, Warner Mountain Goshawks preyed more heavily on mammalian than avian prey species. Of the 221 individuals identified, 126 (57%) were mammals, while 95 (43%) were birds. These results are in accord with the suggestion that there are potentially more mammalian prey species in western North America than in eastern North America.     

History and status of the Franklin's Gull on Malheur National Wildlife Refuge, Oregon

Franklin's Gulls first arrived in southeast Oregon in 1943, but the first nest was not located until 1948. From 1949 to 1964 gull numbers showed annual fluctuations. An increase began in 1965 and continued through 1980. By 1980 an estimated 2500 Franklin's Gulls were nesting on Malheur National Wildlife Refuge, Harney County, Oregon. The species arrives in April and nesting begins by 1 June. Average nest and egg measurements were similar to those from other areas within the species range.     

Diamond Pond, Harney County, Oregon: vegetation history and water table in the eastern Oregon desert

Cores obtained in 1978 from Diamond Pond, Diamond Craters, Harney County, Oregon, as part of the Steens Mountain Prehistory Project, provide a record of vegetation change on the sagebrush/shadscale ecotone and of local and perhaps regional water tables. Pollen, macrofossils, sediments, and charcoal from these radiocarbon-dated cores were analyzed. Varying abundance of juniper, grass, sagebrush, and greasewood pollen, and of aquatic to littoral plant macrofossils reflects changing regional effective moisture and local water table since 6000 B. P. Eleven dates spanning 5200 radiocarbon years and four regionally correlated volcanic ashes establish the dating of seven periods of different moisture regimes: 1. Greasewood and saltbush pollen dominance before 5400 B. P. indicates shadscale desert. Rapid accumulation of alternating silts and medium sands lacking aquatic plant macrofossils and pollen reflects periods of ephemeral ponds with water table 17 m below the present level and considerable erosion of maar slopes. 2. Increasing sagebrush pollen from 5400 to 4000 B. P. indicates sagebrush expansion into shadscale desert. Scirpus, Rumex, Ceratophyllum, and Polygonum persicaria macrofossils and finely laminated clayey silts evidence perennial pond. 3. From 4000 to 2000 B. P. abundant juniper and grass pollen reflects extensive juniper grasslands (juniper seeds from trees growing nearby fell into the pond during this period). Rising charcoal values indicate greater importance of fire. Deepest late-Holocene pond ca 3700 B. P. corresponds with postulated intensive human occupation of northern Great Basin marsh and lake locales. 4. Between 2000 and 1400 B. P. increased sagebrush pollen mirrors reduced effective moisture and reexpanding sagebrush steppe. More abundant Scirpus and Rumex macrofossils evidence shallow pond. 5. From 1400 to 900 B. P. more numerous grass pollen indicates returning greater effective moisture resulting in deeper water with abundant Potamogeton . 6. About 500 B. P. increased greasewood and saltbush pollen evidences drought. Ruppia seeds and pollen and the mollusk Musculium indicate shallow, brackish water. 7. Abundant juniper and grass pollen reflects moister conditions between 300 and 150 B. P. Numerous Ceratophyllum fruits indicate deeper, freshened water. Since the mid- 1800s man and changing climate have encouraged sagebrush reexpansion. Increased Scirpus macrofossils indicate shallower water.     

Western painted turtle in Grant County, 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;} The western painted turtle, Chrysemys picta belli (Gray), is recorded for the first time from Grant County, Oregon. This specimen represents the southwesternmost occurrence of the species in Oregon.     

Current status of cutthroat trout subspecies in the western Bonneville Basin

Recent discoveries of native cutthroat trout populations in desert mountain ranges on the western fringe of the Bonneville Basin have prompted intensified management efforts by state and federal agencies. Analysis of Snake Valley cutthroat specimens in Trout Creek, Deep Creek Mountain Range, Utah, indicate this is a pure strain of the trout which once inhabited Pleistocene Lake Bonneville and which was thought to be extinct in Utah. The Snake Valley cutthroat is similar to Salmo clarki utah of the eastern Bonneville Basin; however, electrophoretic and morphomeristic analysis show unique genetic differences brought about by long - term isolation (8,000 years) from the remainder of the Bonneville Basin cutthroat. This cutthroat is a common ancestor to several other limited cutthroat populations within the basin in Nevada. In May 1977 the BLM withdrew from mineral entry about 27,000 acres within the Deep Creek Mountains for protection of this salmonid cutthroat and other unique resources on the range. Results of 1977 stream surveys on the Pilot Peak Mountain Range, Utah, indicate the presence of the threatened Lahontan cutthroat, Salmo clarki henshawi, in one isolated stream.     

Conservation, status, and life history of the endangered White River spinedace, Lepidomeda albivallis (Cyprinidae)

Lepidomeda albivallis (White River spinedace), a fish species endemic to the White River, Nevada, appeared headed toward extinction. In 1991 only 1 population remained, and it comprised fewer than 50 individuals in a 70-m stream reach. We monitored population recruitment and distribution and studied life history and habitat use from 1993 through 1998. We determined that L. albivallis was not reproducing and was continuing to decline, and as an emergency measure we relocated the population (14 in spring 1995 and 6 in spring 1996) downstream 200 m to a secure habitat that we judged more favorable for reproduction. The relocated population reproduced, and by September 1998 it had increased to 396 individuals that inhabited more than 1 km of stream including both pond and stream habitats. In streams they oriented near the bottom but frequently moved up in the water column to strike at drift items. Gut analysis of museum specimens indicated L. albivallis is omnivorous but feeds primarily upon aquatic invertebrates. Conservation of L. albivallis will require reestablishing additional populations within its former range.     

Interactions among squirrels, mycorrhizal fungi, and coniferous forests in Oregon

We examined the mycophagy (ingestion of fungi) of squirrels of five genera and eight species in the coniferous forests of Oregon. Data from 644 dietary samples demonstrated that squirrels of all eight species are mycophagous and eat the belowground fruiting bodies of at least 26 genera of mycorrhizal fungi. Four species are primarily arboreal and active throughout the year; the other four are primarily terrestrial and hibernate during winter. Of the squirrels examined, only the northern flying squirrel ( Glaucomys sabrinus [Shaw]) is nocturnal and almost exclusively a fungivore. The flying squirrel is used to illustrate the dynamics of all the squirrels in association with hypogeous mycorrhizal fungi, nitrogen-fixing bacteria, yeast, and coniferous trees in Oregon forests because we have studied it the most. Squirrels may prove to be vital links among different processes within temperate coniferous forests.     

Coexistence of two species of sucker, Catostomus , in Sagehen Creek, California, and notes on their status in the western Lahontan Basin

The observed distribution and relative abundance of two morphologically similar species of sucker, Catostomus , have shifted dramatically over the past four decades in Sagehen Creek and nearby streams in eastern California. The mountain sucker, C. platyrhynchus , formerly abundant and more numerous than the Tahoe sucker, C. tahoensis , has become relatively rare and during this study was consistently less abundant than the Tahoe sucker at all eastern California sites in 1983. Similar shifts in abundance were not seen at the three Nevada sites. Behavioral observations and data on spatial and temporal patterns of habitat use, collected in Sagehen Creek between May and September 1982 and 1983 using a snorkel survey method, indicate nearly complete overlap between mountain and Tahoe sucker habitat use and an absence of any agonistic behavioral interaction between species. The decline of the mountain sucker in these areas is likely the result of an interaction of loss of habitat due to reservoir construction and destructive management practices. These changes may have led to the elimination of isolating mechanisms between the two species and may be increasing the opportunity for introgressive hybridization.     

Fall diet of blue grouse in Oregon

The early fall diet of Oregon blue grouse ( Dendragapus obscurus pallidus ) from Wallowa County, Oregon, was determined from 145 crops obtained during 1981 and 1982. Of more than 50 plant and animal foods in the diet, short-horned grasshoppers ( Acrididae ), prickly lettuce ( Lactuca serriola ), yellow salsify ( Tragopogon dubius ), wild buck-wheat ( Eriogonum spp.), and snowberry ( Symphoricarpos albus ) occurred in 30% or more of the crops and collectively amounted to 68% of the diet by weight. Seven of the 12 most common foods were consumed differentially by the four sex and age classes of birds. Results indicated that blue grouse foraged in forest and grassland habitats.     

The fishes of Saint Helena Island,South Atlantic Ocean. II. The pelagic fishes

The pelagic fishes of St Helena Island, South Atlantic Ocean (15°58′S 5°43′W) are reviewed. A checklist of 53 taxa of pelagic fishes, with notes on fisheries significance, ecology and geographical distribution, is presented. Twelve of the taxa have not before been recorded at St Helena. Of particular interest are records of three primarily Indo-Pacific species: Decapterus muroadsi (Temminck and Schlegel), Uraspis helvola (Forster) and Scomberomorus commerson (Lacepède). Apart from U. helvola, which is known also from Ascension Island, these species are not otherwise recorded in the Atlantic Ocean.

Of the 49 pelagic fishes whose identities are clear, 81·6% are wide-ranging species known from both the Atlantic and Indo-Pacific regions, 12·2% are pan-Atlantic warm-water species and 4·1% are eastern Atlantic species which reach their western limit in the central Atlantic. In addition, the subspecies Platybelone argalus trachura is found only at St Helena and Ascension.

The principal pelagic species caught by St Helena fisheries are Katsuwonus pelamis, Thunnus albacares, T. obesus, T. alalunga, Scomber japonicus, Acanthocybium solandri and Pseudocaranx dentex, which together accounted for almost 95% of fish landings in 1982–1983 fiscal year.     

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.     

Hatching chronology of Blue Grouse in northeastern Oregon

Hatching chronology of Blue Grouse ( Dendragapus obscurus ) in northeastern Oregon was determined from 431 immatures examined from 1981 to 1985. Young hatched from 1 May through 8 July; median hatching dates for the five years ranged from 27 May to 5 June. Peak hatching in Oregon occurred from one to four weeks earlier than in most portions of the range of Blue Grouse but were similar to north central Washington and Idaho. Variations in hatching dates possibly were related to rainfall.       

Winter and early spring bird communites in grasslands, shrubsteppe, and juniper woodlands in central Oregon

We compared winter (December, January, and February) and early spring (March and April) bird communities among 4 successional stages that included grassland, shrubsteppe, juniper-shrubsteppe, and old-growth juniper woodland in central Oregon. Birds were surveyed monthly from December through April in 1998/1999 and 1999/2000 using the point count method to estimate relative abundance of birds (individuals ? transect –1 year –1 ). We used distance sampling to correct for potential bias in estimating abundance and density among successional stages. A total of 4513 birds (32 species) were detected. Relative abundance of total birds (all species combined) was similar in the juniper-shrubsteppe and old-growth woodland (48.7 and 48.9 individuals ? transect –1 , respectively) but 6 times greater than in the grassland and shrubsteppe (8.0 and 7.7 individuals ? transect –1 , respectively) during the 5-month period. Total density of birds was greater in old-growth juniper woodland and juniper-shrubsteppe than in grassland or shrubsteppe. However, median bird species richness in 1998/1999 was highest in grassland and lowest both in shrubsteppe and juniper-shrubsteppe, and in 1999/2000 it was highest in shrubsteppe and lowest in juniper-shrubsteppe and oldgrowth juniper woodland. American Robins and Townsend's Solitaires were the most abundant species in junipershrubsteppe and old-growth juniper woodland during the winter months. Sage Sparrows and Horned Larks were the most abundant species in shrubsteppe during winter, and Horned Larks were most abundant in grasslands during the early spring transition period prior to nesting. Our results indicate that a different suite of species use these successional stages during the nonbreeding season. If avifauna conservation is a part of long-term management goals, a broad range of successional stages should be maintained on the landscape to provide habitat for a variety of avian species throughout the year.     

Food of cougars in the Cascade Range of Oregon

Animal and nonanimal items were identified in the digestive tracts of 61 cougars ( Felis concolor ) collected between 1978 and 1984 from the western slopes of the Cascade Range in Oregon. Forty - two (69%) of the cougars were taken by hunters in December and January, 18 (30%) were killed at other times of the year because of their proximity to livestock, and one animal was illegally killed in November. Black-tailed deer ( Odocoileus hemionus columbianus ) was the most common prey item, although domestic sheep ( Ovis airies ), porcupines ( Erethizon dorsatum ), and a variety of small mammals were also recorded. Masticated grass was the most common nonanimal item.