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171.
Named as a new species from the House Range of Millard County, Utah, as Primula domensis Kass & Welsh. 相似文献
172.
Ruffed Grouse ( Bonasa umbellus ) drumming log and habitat use in Grand Teton National Park, Wyoming
We described 15 Ruffed Grouse ( Bonasa umbellus ) drumming logs and adjacent habitat within Grand Teton National Park, Wyoming. Drumming logs and adjacent habitat differed from 30 random non-drumming sites. Drumming logs had fewer limbs (8; P = 0.003) and a smaller percentage of bark remaining (12%; P = 0.0001). These logs were in advanced stages of decay but were still firm to the touch. Additionally, drumming logs were found close to clearings but in areas with increased amounts of undergrowth and mature trees. Adjacent habitat analysis (0.04-ha circular plot centered on logs) indicated drumming locations had significantly greater average canopy height, more vegetative cover consisting of conifer and total canopy cover, and more vertical foliage between 0.3 m and 3.0 m in height. Adjacent habitat was in advanced stages of maturity as indicated by significant numbers of both large-diameter logs and largediameter lodgepole pine ( Pinus contorta ) and quaking aspen ( Populus tremuloides ) snags. Tree species dominating the canopy and subcanopy were large-diameter Engelmann spruce ( Picea engelmannii ), lodgepole pine, and quaking aspen. Subalpine fir ( Abies lasiocarpa ) and quaking aspen saplings were more numerous at used sites. Ruffed Grouse drummed in coniferous areas within close proximity of quaking aspen. 相似文献
173.
Roots of 15 Mojave Desert plant species were assessed for arbuscular mycorrhizal (AM) colonization in spring and autumn 1999. Another 19 species were assessed in autumn only. Perennial species were AM colonized, whereas annual species contained very low levels of AM hyphae or were nonmycorrhizal. The nonnative tree Tamarix ramosissima was also nonmycorrhizal. Levels of hyphae changed over the season in 2 species, arbuscle levels increased in 1 species, and vesicles decreased in 7 species. Mycorrhizal inoculum potential (MIP) was assessed in the soils associated with spring-collected plants. All soils were found to contain MIP. MIP values were not correlated with AM root colonization. 相似文献
174.
Passerine response to roads associated with natural gas extraction in a sagebrush steppe habitat 总被引:1,自引:0,他引:1
Natural gas extraction and field development are pervasive throughout the sagebrush steppe of Wyoming. We conducted this study to determine how roads associated with natural gas extraction affect the distribution of breeding songbirds in sagebrush steppe habitat. The study encompassed dirt and paved roads in the Jonah Field II and Pinedale Anticline Project Area in Sublette County, Wyoming. Sites are dominated by Wyoming big sagebrush ( Artemisia tridentata ), and common passerines include sagebrush obligates: Brewer's Sparrows ( Spizella breweri ), Sage Sparrows ( Amphispiza belli ), and Sage Thrashers ( Oreoscoptes montanus ); and non-obligates: Horned Larks ( Eremophila alpestris ) and Vesper Sparrows ( Pooecetes gramineus ). Species relative density was measured using 50-m-radius point counts during spring 1999 and 2000. Four roads with low traffic volumes (700-10 vehicles per day) were surveyed and point counts were centered at variable distances from the road surface such that relative densities were measured 0-600 m from the road's edge. Density of sagebrush obligates, particularly Brewer's and Sage Sparrow, was reduced by 39%-60% within a 100-m buffer around dirt roads with low traffic volumes (700-10 vehicles per day). While a 39%-60% reduction in sagebrush obligates within 100 m of a single road may not be biologically significant, the density of roads created during natural gas development and extraction compounds the effect, and the area of impact can be substantial. Traffic volume alone may not sufficiently explain observed declines adjacent to roads, and sagebrush obligates may also be responding to edge effects, habitat fragmentation, and increases in other passerine species along road corridors. Therefore, declines may persist after traffic associated with extraction subsides and perhaps until roads are fully reclaimed. 相似文献
175.
176.
Stanley L. Welsh 《西北部美国博物学家》2011,50(4)
The status of the name Oxytropis borealis DC. is reviewed as it applies to North American plants. A summary of the infraspecific taxa is presented, and several nomenclatural combinations are proposed: Oxytropis borealis DC. var. hudsonica (Greene) Welsh; O. borealis var. sulphurea (Pors.) Welsh; O. borealis DC. var. viscid (Nutt.) Welsh. One new taxon, Oxytropis borealis DC. var. australis Welsh, is described from Utah and Nevada, USA. 相似文献
177.
The status of 382 vascular plant taxa with distribution in Utah is presented. Some 66 species are possibly endangered, 198 threatened, 7 extinct, and 20 extirpated within the state; 4 species have questionable taxonomic status. Included in the list are nearly 225 species of endemic plants, many of which are among the possibly endangered, threatened, and extinct or extirpated plants. Bibliographic citations, type locality, status, and distribution by counties is included for each species or infraspecific taxon. Two new species are described: Psoralea pariensis and Eriogonum natum. One new name, Astragalus barnebyi, is proposed; and one new variety, Eriogonum umbellatum var. deserticum, is proposed. The following new combinations are made: Cycladenia humilis var. jonesii; Aralia racemosa ssp. bicrenata; Heterotheca jonesii; Hymenoxys depressa; Xanthocephalum sarothrae var. pomariense; Thelypodium integrifolium var. complanatum; Thelypodium sagittatum var. ovalifolium; Arenaria kingii var. plateauensis; Psorothamnus thompsonae; Najas caespitosus; Oenothera gouldii; Eriogonum corymbosum var. revealianum; Penstemon humilis var. obtusifolius; Penstemon lentus var. albiflorus; and Viola purpurea var. charlestonensis. 相似文献
178.
Thelypodiopsis argillacea Welsh and Atwood sp. nov. is described from specimens collected on the Green River Shale Formation in Uintah County, Utah. 相似文献
179.
Stanley L. Welsh 《西北部美国博物学家》2011,38(1)
Endangered and threatened plants of Utah are reevaluated. The lists are brought up to date, and species now known to be common are recommended to be removed from the proposed lists. Additional species are proposed to be added, including the new species, Astragalus montii Welsh. 相似文献
180.
In 1984 (a dry year), Tule Meadow, in the Sierra National Forest, California, was well grazed after several years of light use. This situation provided the opportunity to study responses of Nebraska sedge ( Carex nebraskensis ), an important forage species in mountain meadows, to protection and grazing. Rooted shoot frequencies and densities in fall 1984 and spring 1985 were the same within an exclosure and on the grazed area. Residual herbage (shoot weight) in fall and shoot heights in spring were greater within the exclosure. Lower spring shoot heights on the grazed area may relate to fall regrowth and reduced insulation induced by grazing. Nitrogen and potassium content of fall herbage was greater on the grazed area. Phosphorus content was the same both inside and outside the exclosure. 相似文献