首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
《Journal of Natural History》2012,46(39-40):2585-2591
In the present study, the cloning and sequence analysis of interleukin‐6 (IL‐6) from the giant panda (Ailuropoda melanoleuca) were described. Sequencing revealed that IL‐6 complementary DNA contains a 636 base‐pair open reading frame encoding 211 amino acids. Homology analyses indicated that the identity levels of nucleotide and deduced amino acid sequences of IL‐6 between the giant panda and other species in Carnivora ranged from 90.5% to 85.6% and from 82.9% to 76.5%, respectively. Phylogenetic analyses based on nucleotide and amino acid sequences showed that the harbour seal shared a closer relationship with the giant panda than other carnivores (ursids not included). The functionally important domains and sites that have previously been recognized in other carnivores were all observed in the IL‐6 sequence of the giant panda. These findings suggest that the complementary DNA fragment cloned is indeed the IL‐6 molecule with biological activity and can be used in immunological studies of the giant panda.  相似文献   

2.
We studied summer habitat use by Columbian Sharp-tailed Grouse ( Tympanuchus phasianellus columbianus ) in western Idaho during 1983-85. Vegetative and topographic measurements were recorded at 716 locations of 15 radio-tagged grouse and at 180 random sites within the major vegetation/cover types in the study area. The mean size of summer home ranges was 1.87 ± 1.14 km 2 . Of eight cover types identified in the study area, individual grouse used the big sagebrush Artemisia tridentata ) cover type more than or in proportion to availability, the low sagebrush ( A. arbuscula ) in proportion to availability, and avoided the shrubby eriogonum ( Eriogonum spp.) type. Characteristics of the big sagebrush cover type that Sharp-tailed Grouse preferred include moderate vegetative cover, high plant species diversity, and high structural diversity. Grouse used areas of dense cover (i.e., mountain shrub and riparian cover types) primarily for escape cover. Compared with random sites, grouse selected areas with (1) greater horizontal and vertical cover, (2) greater canopy coverage of forbs typically decreased by livestock grazing, (3) greater density and canopy coverage of arrowleaf balsamroot ( Balsamorhiza sagittata ), and (4) greater canopy coverage of bluebunch wheatgrass ( Agropyron spicatum ) in the big sagebrush cover type in 1984 and the low sagebrush cover type in 1985. The importance of the native perennials arrowleaf balsamroot and bluebunch wheatgrass became apparent during a drought year when many exotic annuals dried up and provided no cover. Overall, grouse selected vegetative communities that were least modified by livestock grazing.  相似文献   

3.
Previous studies of nest-site selection on a fine scale may reveal limiting resources within habitat types. The red-billed leiothrix (Leiothrix lutea Scopoli, 1786) is a common bird species that lives in the subtropical forests of Asia. Despite many reports of this species from introduced populations, little information has been obtained from its native range. From 2011 to 2013, we studied nest-site selection of red-billed leiothrix at micro-scales in Daweishan Nature Reserve, Hunan Province, central China. A total of 363 nests were found in five vegetation types. We measured the habitat variables and constructed nest-site selection models for nests found in the forest and scrub-grassland. Among the 18 variables measured in the forest, six variables were selected to construct the nest-site selection model: distance to forest edge (DTE), distance to water (DTW), vegetation comprehensive coverage, tree coverage, bamboo coverage and shrub height. According to Akaike’s information criterion, the best model consisted of five of these variables (excluding vegetation comprehensive coverage), and distance to forest edge, distance to water, tree coverage and bamboo coverage had negative effects on nest-site selection. In scrub-grassland, the DTE, DTW, and bush coverage (BUC) were selected from the 13 variables measured, and, accordingly, the best model consisted of DTE and BUC. Model averaging suggested that BUC had a positive effect on nest-site selection. In contrast, DTE has a reverse effect. In addition, DTE differed significantly between successful and failed nests in forest and scrub-grassland. More successful nests were found near the forest edge. Taken together, these findings emphasise the power of fine-scale habitat selection models in identifying relevant habitat variables with a significant effect on preferred habitat and eventually, breeding success.  相似文献   

4.
《Journal of Natural History》2012,46(21-22):1321-1335
The use of microhabitats by small mammals was investigated in an area of Pampas in southern Brazil. We used 10 transect lines with 12 live-traps during six fieldwork sessions between June 2009 and April 2010. Sixteen environmental variables measured were summarized by a principal component analysis (PCA). Richness, total abundance and abundance of each species captured were correlated with the first two PCA axes. The environmental variables were also correlated with the small-mammal abundance through a canonical correspondence analysis (CCA). The first axis was related to variables that characterize forest environments, such as canopy cover and number of trees, and the second axis (with which the species richness and abundance were associated) was related to water, arthropods and herbaceous vegetation. The CCA and PCA showed a significant effect of microhabitat variables on species occurrence. In view of the great variability of environments in the study area and the correlation of the species with the environment variables measured, the degree of heterogeneity seemed to be an important factor associated with the small-mammal variation among microhabitats.  相似文献   

5.
6.
7.
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   

8.
We compared physical and vegetative habitat characteristics at 14 dam sites occupied by beaver ( Castor Canadensis ) with those at 41 random unoccupied reaches to identify features important to dam-site selection in the Long Creek basin, Grant County, Oregon. Stream reaches with dams were shallower and had a lower gradient than unoccupied reaches. Beaver did not build dams at sites with a rock substrate. Bank slopes at occupied reaches were not as steep as those at unoccupied reaches; and occupied stream reaches had greater tree canopy cover, especially of thinleaf alder ( Alnus tenuifolia ), than did unused reaches. A discriminant model using transformations of bank slope, stream gradient, and hardwood cover classified all beaver dam sites correctly and 35 of 41 random sites as unoccupied sites. The 6 misclassified sites had rock substrates. We also tested four habitat suitability models for beaver in this basin. Three models produced significantly different ( P < .05) scores between occupied and random unoccupied reaches, suggesting that they might have some utility for this region.  相似文献   

9.
10.
《Journal of Natural History》2012,46(41-42):2677-2721
ABSTRACT

Embedded within the interdisciplinary research project ‘Towards an understanding of the structure and function of a Neotropical rainforest ecosystem with special reference to its canopy’ organised by the Austrian Academy of Science, the canopy beetle fauna was surveyed by means of a 42 m tall tower crane. This paper presents results of the chrysomelid beetle fauna observed and collected at canopy trees for 1 year. A total of 1783 adult leaf beetles were collected, representing 117 morphospecies (Bruchinae are not included) including 31 singletons. The most abundant family was Galerucinae sensu stricto with 827 individuals (46% of collection). The most speciose subfamilies were Galerucinae sensu stricto followed by Alticini, Cryptocephalinae and Eumolpinae. Nineteen species collected with at least two individuals were restricted to a single tree species whereas 68 species were found to feed on several canopy host trees. Only a few species fed on leaves; these were in Cassidinae, Cryptocephalinae, Eumolpinae and Galerucinae. Strikingly, most canopy chrysomelids were collected at flowers of canopy trees, although some species fed also on extrafloral nectaries or fruits. Alticini were restricted predominantly to flowers, but Cryptocephalinae, Eumolpinae and Galerucinae revealed broader plasticity in host tissue selection. Insights into beetle seasonality, diurnal/nocturnal activity and intra-canopy migration are provided. Abundant flower-visiting species occurred on their host trees commonly over the entire flowering season, with their abundances often correlated with the number of open flowers. After termination of one tree’s flowering season, many flower-visiting leaf beetles moved to other flowering trees. Certain congeneric species of Galerucinae and Eumolpinae occurred together at their host plants within the same periods.  相似文献   

11.
Many rangelands in the southwestern United States provide quality habitat for Northern Bobwhites ( Colinus virginianus ). These same habitats are frequently managed for livestock production and thus are subjected to various brush management practices that are meant to enhance forage production. Bobwhites rely on woody cover for food, thermal and loafing cover, and protection from avian predators. Implementing brush management practices that reflect bobwhite requirements is important for managing usable space and viable populations. We described the structural vegetative characteristics associated with bobwhite locations and random locations on native rangelands in the upper Rolling Plains of Texas that are dominated by honey mesquite ( Prosopis glandulosa ) and managed with aerial herbicide and prescribed fire. We also used binary logistic regression to model habitat selection; the initial model was built using 67% of the data ( n = 179 used-random paired points) and then validated using the remaining 33% of the data ( n = 88 used-random paired points). Locations used by bobwhites had significantly larger mean values of percent brush canopy cover, visual obstruction, and angle of obstruction than did random locations; random locations had a greater mean value of percent bare ground than locations used by bobwhites. The resulting logistic regression model contained only the angle of obstruction; the model had an 80% probability of correctly classifying used and random locations based on the area under the receiver operating curve (ROC). The model maintained a high classification probability when applied to the smaller validation data set, with an area under the ROC of 0.78.  相似文献   

12.
A synecological study of aquatic macrophyte plant communities was conducted across northern Idaho and western Montana during the summers of 1997, 1998, and 1999. A total of 111 natural and man-made water bodies were sampled based on a stratification of environmental variables thought to influence plant species distribution (i.e., elevation, landform, geology, and water body size). Plant species foliar cover data were used to develop a hierarchical, floristic-based community type classification with TWINSPAN and DECORANA software. Six planmergent (conspicuous portion of vegetative plant body on the water surface) and 24 submergent (vegetative plant body found primarily underwater) community types were identified. Multivariate analysis indicated that all community types displayed significant differences in plant species composition, and the Sorensons floristic similarity between communities averaged 10% for planmergent and 8% for submergent types. Canonical correspondence analysis was used to inspect relationships between abiotic factors and plant species abundance. Results of this analysis indicated some relationships between species distributions and abiotic factors; however, chance introduction of plant species to water bodies is a process considered to be equally important to the presence of the community types described.  相似文献   

13.
The purposes of this study were to develop a multivariate statistical model related to plant succession, to classify by seral stage, and to monitor succession in Wyoming big sagebrush shrubsteppe habitat ( Artemisia tridentata ssp. wyomingensis / Agropyron smithii–Bouteloua gracilis ) in Thunder Basin National Grassland, Wyoming. This model can be used by range and wildlife managers to evaluate management alternatives by assessing changes in plant species cover and composition within and between seral stages. Four ecological seral stages that represent early to late succession were quantitatively identified with an estimated 92% accuracy. Three key plant species provided the necessary information to define seral stages and monitor trends. Percent canopy cover and percent frequency (used to calculate index values: % canopy cover × % frequency of occurrence) of Wyoming big sagebrush ( Artemisia tridentata ssp. wyomingensis ), western wheatgrass ( Agropyron smithii ), and blue grama ( Bouteloua gracilis ) are the only field measurements required for this model.  相似文献   

14.
The population structure of 2 Great Basin odonate species was assessed using protein electrophoresis. Analyses included 7 populations of Sympetrum corruptum (suborder Anisoptera), a migratory and highly mobile dragonfly, and 8 populations of Enallagma carunculatum (suborder Zygoptera), a weak flier that is not known to migrate far from natal water sources. Though we expected the damselfly ( E. carunculatum ) to show greater genetic isolation than the dragonfly ( S. corruptum ), both species apparently had high levels of gene flow (theta = 0.0604 for S. corruptum , theta = 0.0485 for E. carunculatum ) and showed no evidence for isolation by distance. These results suggest that both species are highly vagile and that the most important factors affecting population structure of these odonates may be ecological conditions such as habitat patchiness and the ephemerality of water sources.  相似文献   

15.
We translocated 196 Sage Grouse ( Centrocercus urophasianus into Sawtooth Valley, Idaho, during March-April 1986-87 to augment a small resident population. Forty-four grouse equipped with radio transmitters were monitored through spring and summer. Nest sites ( n = 6) had greater ( P = .032) horizontal cover than did independent random plots ( n = 7). During summer, grouse used sites ( n = 50) with taller live and dead shrub heights, greater shrub canopy cover, and more ground litter ( P n = 50) 50-300 m from use sites. Distance to edge and mountain sagebrush ( Artemisia tridentata vaseyana ) density best separated use sites from independent random plots in logistic regression analysis and correctly classified 64% of the use sites and 78% of the independent random plots. Sage Grouse used sties that had narrower frequency distributions for many variables than did independent plots ( P < .04), suggesting selection for uniform habitat.  相似文献   

16.
Percent tree canopy cover in a ponderosa pine ( Pinus ponderosa ) forest of northeastern California was estimated by the point intercept spherical densiometer and ocular methods. Estimates derived by the two methods were similar (P > .05). The ocular method is recommended when understory vegetation is tall or clumped instead of randomly distributed, or if available field time limits sample size.  相似文献   

17.
Habitat use and selection by Merriam's Wild Turkeys ( Meleagris gallopavo merriami ) in Wasco County, Oregon, was studied during 1981-82. This turkey population selectively used forested cover types (such as ponderosa pine-Douglas-fir-oak, ponderosa pine-oak) characterized by a variety of structural features, species, and age classes. The population used single species forested cover types (oak, ponderosa pine) less than expected, used nonforested cover types in proportion to their availability, and avoided forested cover types with structure simplified by logging activities. The four age and sex classes had large seasonal home ranges ( ̄x = 1,615 ha); the smallest home ranges were exhibited by adult males in winter and the largest were shown by subadult males in fall. In most instances, turkeys used cover types as they were available. We suggest that structural complexity of vegetation, both within and among cover types, is an important component of habitat for Merriam's Wild Turkeys that should be considered in the evaluation of potential release sites and in habitat management plans.  相似文献   

18.
Western juniper ( Juniperus occidentalis spp. occidentalis Hook.) expansion in the northern Great Basin has reduced shrubsteppe productivity and diversity. Chainsaw cutting of western juniper woodlands is commonly applied to remove tree interference and restore sagebrush plant communities. Studies assessing understory response following cutting have been limited to early successional stages and have not evaluated the effects of western juniper debris on plant succession. Cutting western juniper produces a large amount of debris which is commonly left on site, occupying a significant portion of treated areas. This study evaluated successional dynamics spanning 13 years after western juniper cutting. Four 0.45-ha blocks were selected on Steens Mountain in southeastern Oregon. Western juniper cover averaged 26% and mature tree density averaged 250 trees ? ha –1 . Blocks were cut in late summer 1991. Understory standing crop, cover, and density were compared among 3 locations: old canopy litter mats (canopy), interspace, and area underneath cut western juniper (debris). In the interspace, perennial grasses increased in cover and in standing crop relative to other functional groups. In canopy and debris locations, species composition shifted in the 6th year after cutting as annual grass cover, density, and standing crop increased. However, by 2003, perennial grass biomass was 2 times greater than annual grass biomass in canopy and debris locations. Because annual grasses increased in areas of debris accumulation, managers need to be cognizant of western juniper treatments that create safe sites that are favorable to the establishment of weedy species. Retaining western juniper debris on this site did not increase establishment and growth of perennial grasses compared to the interspace. A shift in perennial grass dominance from Thurber's needlegrass ( Achnatherum thurberianum [Piper] Barkworth) to bottlebrush squirreltail ( Elymus hystrix [Nutt.] Smith) occurred in areas of debris accumulation. Our results demonstrated that long-term vegetation evaluations are necessary to properly assess management activities and disturbance.  相似文献   

19.
Habitat modification, pollution, overfishing, poaching, competition from non‐indigenous species, and diseases have led to the extinction in Europe of many populations of indigenous crayfish. Under the rationale that any programme of reintroduction should be preceded by a thorough understanding of habitat requirements of the species of concern, we studied the microhabitat use of an Austropotamobius pallipes population in Tuscany, central Italy. Microhabitat use was assessed for water depth, current velocity, substrate, percentages of boulders, underwater tree roots, and in‐stream vegetation cover. Results show that A. pallipes' habitat use is size‐partitioned. Smaller individuals mostly occupy stream edges in shallow waters with submerged roots, whereas larger individuals use deeper waters, often associated with boulders. Crayfish spatial distribution is restricted mostly to the microhabitats characterised by extensive cover and slow current velocity. The study highlights the importance of habitat heterogeneity and cover elements for the protection of this indigenous species.  相似文献   

20.
From 1990 to 1992 we surveyed for Flammulated Owls ( Otus flammeolus ) in 3 areas in Idaho: Salmon National Forest (SNF), Payette National Forest and adjacent Hells Canyon National Recreation Area (PNF-HCNRA), and Nez Perce National Forest (NPNF). We also collected and summarized information on all historic and modern records of Flammulated Owls in Idaho. Flammulated Owls were detected on 65% of 68 routes (2-16 km in length) surveyed at densities ranging from 0.04 to 1.25 singing males/40 ha. Owls were detected on survey routes as early as 10 May and as late as 23 July. Mean percent canopy cover estimated at owl locations on the PNF-HCNRA and NPNF study sites ranged from 52% to 64%, while shrub cover ranged from 16% to 21% and ground cover was 39% to 49%. Our surveys and summary of distributional records indicated that Flammulated Owls occur throughout the montane forests of Idaho in old or mature stands of open ponderosa pine ( Pinus ponderosa ), Douglas-fir ( Pseudotsuga menziesii ), and stands co-dominated by those 2 species. Fire suppression and timber harvest activity in ponderosa pine forests represent 2 main threats to the species' future security in Idaho. More research on the effects of various silvicultural treatments on Flammulated Owl populations is warranted.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号