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排序方式: 共有143条查询结果,搜索用时 15 毫秒
1.
小竹鼠在我国仅分布于云南西部热带亚热带地区。主要生活于山坡稀树灌丛、阔叶林、橡胶园及居民点附近。在盈江县分布于海拔300-950米地带。取食、休息、繁殖主要在洞道内。洞系由洞口、取食道、趋避道、窝及“厕所”组成。食物主要有棕叶芦、芦竹及三叶橡胶等18种,尤喜食橡胶树主根,因而对橡胶树危害很大。13号标本中雌7雄6。在盈江每胎2-3只,以2只为多。成年小竹鼠过独居生活,雌雄各有自己的洞系。 相似文献
2.
在有人为干扰的森林景观中开展鹿科动物适宜生境分布研究,对于解决大尺度生境保护与小面积森林经营的矛盾问题有着重要的参考意义,也符合我国林区的现实需求.2013—2015年冬季进行的多次野外调查收集196处鹿科动物出现点信息,将这些点作为分布点数据,选取地形、景观类型、植被特征和人类干扰4类17种因子作为环境变量,利用最大熵模型方法,分析4种林下经营面积情景下小兴安岭铁力林业局马鹿和狍的潜在适宜生境分布特征及其对环境因子的响应.结果表明:模型预测精度达到优秀水平,稳定性好,鹿科动物的适宜生境主要集中在东部区域;不同情景下,两种鹿科动物的主要环境影响因子相似,均为距农田距离、距居民点距离、距河流距离、距营林区距离和海拔因子,其中,距营林区距离因子的贡献率稳定在4%~6%;两种鹿科动物躲避人类经营活动干扰的距离(1200~1300 m)较为接近.在无林下经营情景中,鹿科动物的适宜生境分布较广、面积较大;随着经营面积的增大,适宜生境面积减少;当经营面积扩大到现实情况的2~3倍时,鹿科动物栖息地面积缩减较为严重. 相似文献
3.
The moose (Alces alces cameloides) population in northeastern China is on the southernmost edge of its distribution in Asia. A survey was conducted to determine
moose resource selection and the effects of human disturbance on moose in a study area of 20,661 ha located on the northwestern
slope of the Lesser Khingan Mountains, located in northeastern China. Predictive models of resource selection were developed
using logistic and autologistic regression. All models considered resource variable selection at two spatial scales, patch
and landscape. At the patch scale, moose preferred larger birch (Betula platyphylla) patches, but avoided larger tamarack (Larix gmelinii) patches. At the landscape scale, moose preferred higher densities of tamarack patches, i.e., heterogeneity of tamarack stands,
selected areas with more abundant annual shoots, terrain conducive to better concealment, higher altitudes and areas saturated
with soil moisture. Roads and forest harvest intervals were identified as important human disturbance factors. This is the
first time that moose have been reported to avoid roads, and the avoidance distance was nearly 3 km. We believe that in this
region moose under the influence of roads are behaviorally plastic, compared with the indifference of moose to the presence
of roads in other regions. Moose avoided forest areas logged more than 3 years previously and preferred areas logged 1–2 years
previously. In addition, it may be necessary to monitor the effect of the dynamic of density of roe deer on the spatial distribution
of the moose population. 相似文献
4.
We investigated the relationship between eggsize variation and (a) egg hatching success, (b) chick survival to fledging and
recruitment, and (c) adult female survival, over 12 years in the lesser snow goose (Anser caerulescens caerulescens). By comparing the means and variances of egg size for successful and unsuccessful eggs, our aim was to assess the relative
fitness of eggs of different sizes and to determine the type of selection operating on egg size in this species. As both egg
size and reproductive success vary with age in the lesser snow goose we controlled for the effects of female age. Egg-size
variation is very marked in this population, varying by up to 52% for eggs hatching successfully. However, there was no relationship
between egg size and post-hatching survival of goslings to fledging or recruitment, either within or between broods, pooling
across years. Egg size varied significantly between successful and unsuccessful clutches in only 2 of 33 individual year comparisons.
First-laid eggs surviving to onset of incubation, and eggs hatching successfully, were on average larger than unsuccessful
eggs, but this was probably due to the confounding effects of female age-specific and sequence-specific egg survival. Variance
of egg size differed significantly between successful and unsuccessful eggs in only 3 of 24, and 0 of 21, individual year
comparisons for pre- and post-hatching survival respectively. We therefore found little evidence for a relationship between
egg-size variation and offspring fitness, or for strong directional, normalising or diversifying selection operating on egg
size, in the lesser snow goose. In addition, there was only weak support for the hypothesis that egg-size variation is maintained
by temporal variation in selection pressure (sensu Ankney and Bisset 1973). It is likely that egg-size variation represents the pleiotropic expression of alleles affecting
more general physiological or metabolic processes. While this does not rule out the existence of alleles with more direct
effects on egg size we suggest that their contribution to heritable egg size is small. 相似文献
5.
土壤细菌是森林生态系统的一个重要组成成分, 是生态系统中物质循环和能量流动的重要参与者, 细菌群落组成和生物多样性是反映土壤生态功能的重要指标。本文利用高通量测序技术分析了大亮子河国家森林公园内红松(Pinus koraiensis)林、落叶松(Larix gmelinii)林、蒙古栎(Quercus mongolica)林、枫桦(Betula costata)林、针阔混交林、灌木林和草甸等7种不同生境土壤细菌群落组成和多样性的差异性, 探讨该地区土壤细菌群落对不同生境的响应, 为地区森林生态系统的经营管理及生态系统稳定性的维护提供科学理论基础。在门的水平上, 各生境的细菌群落组成基本一致, 其中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)和疣微菌门(Verrucomicrobia)在7种生境土壤中相对丰度均大于10.0%, 是细菌中的优势菌门。在属的水平上, 共测得245个菌属, 各样地共有属118个, 占总属数的48.2%, 占总相对丰度的97.8%; 优势菌属分别为Spartobacteria_ genera_incertae_sedis、Gaiella、Gp16、Gp4, 占总相对丰度的47.0%, Spartobacteria_genera_incertae_sedis在7种生境土壤中丰度均最高。7种生境下的土壤细菌多样性和土壤理化因子存在着显著的差异, 红松林的土壤细菌群落多样性和丰富度均高于其他生境。土壤pH是大亮子河森林公园影响土壤细菌多样性的关键因子。 相似文献
6.
Laura M. Bellis Mónica B. Martella Joaquín L. Navarro Pablo E. Vignolo 《Biodiversity and Conservation》2004,13(14):2589-2598
In this work we report results of radiotracking studies on the movements and home range sizes of two near-threatened species, the greater rhea (Rhea americana) and the lesser rhea (Pterocnemia pennata pennata) in relation to different land use regimes. We radiomonitored greater and lesser rheas for 3 years in their respective habitats: the Pampas and the Patagonia regions. We chose two study areas in each habitat with similar agricultural activities and different hunting control. We did not find significant differences in movements and home range size between study areas of each species. This suggests that disturbance caused by human presence in the areas did not affect rhea spacing behaviors. Moreover, lesser rheas showed larger home range and movements than greater rheas, showing that the home range size is not an immutable property of body mass, and that abundance and distribution of food appears to be the main factor that influences the movements and home range size of these birds. 相似文献
7.
大小兴安岭可培养细菌的资源多样性 总被引:2,自引:0,他引:2
细菌作为微生物中的重要组成部分, 在有机质的形成与分解、维持生态系统平衡、促进动植物发育等多方面都有着重要作用。2014-2017年, 我们采用常见培养基分离纯培养法及16S rRNA基因序列分析方法对大小兴安岭地区土壤可培养细菌的群落结构和多样性进行了调查研究。结果表明: 从大小兴安岭地区的17个自然保护区内不同生境的土壤中分离获得3,180个菌株, 隶属于24属120种。其中, 芽孢杆菌属(Bacillus)的种数和株数最多, 分别为38种和2,419株, 是大小兴安岭地区可培养细菌的绝对优势类群(占总株数的76.1%); 其次是短杆菌属(Brevibacterium)(13.0%)。大兴安岭地区的物种数、Simpson多样性指数和Shannon-Wiener指数高于小兴安岭地区。优势类群芽孢杆菌属的枯草芽孢杆菌(B. subtilis)、苏云金芽孢杆菌(B. thuringiensis)、巨大芽孢杆菌(B. megaterium)等有重要的生产及科学研究价值。 相似文献
8.
The parasitic mite Acarophenax lacunatus kills the eggs upon which it feeds and seems to have potential as a biological control agent of stored grain pests. The lack of biological studies on this mite species led to the present study carried out in laboratory conditions at eight different temperatures (ranging from 20 to 41°C) and 60% relative humidity using Rhyzopertha dominica as host. The higher the temperature, the faster: (1) the attachment of female mites to the host egg (varying from 1 to 5 h); (2) the increase in body size of physogastric females (about twice faster at 40°C than at 20°C); and (3) the generation time (ranging from 40 to 220 h). In addition, the higher the temperature, the shorter the maximum female longevity (ranging from about 75 to 300 h). The two estimated temperature thresholds for development of A. lacunatus on R. dominica were 18 and 40°C. The average number of female and male offspring per gravid mite were 12.8 and 1.0, respectively, with sex ratios (females/total) ranging from 0.91 to 0.94 (maximum at 30°C). The net reproductive rate and intrinsic rate of increase also presented maximum values at 30°C (12.1 and 0.04, respectively). 相似文献
9.
Striking difference in response to expanding brood parasites by birds in western and eastern Beringia 下载免费PDF全文
Vladimir Dinets Kristaps Sokolovskis Daniel Hanley Mark E. Hauber 《Journal of Field Ornithology》2018,89(2):117-125
Two species of obligate brood‐parasitic Cuculus cuckoos are expanding their ranges in Beringia. Both now breed on the Asian side, close to the Bering Strait, and are found in Alaska during the breeding season. From May to July 2017, we used painted 3D‐printed model eggs of two cuckoo host‐races breeding in northeastern Siberia to test behavioral responses of native songbirds on both sides of the Bering Strait, with particular attention to species that are known cuckoo hosts in their Siberian range. Each host nest was tested after the second egg was laid and, if possible, again 4 days later with a model of a different type. Although our Siberian study site was also outside the known breeding ranges of the cuckoos, we found that Siberian birds had strong anti‐parasite responses, with 14 of 22 models rejected. In contrast, birds in Alaska had virtually no detectable anti‐parasite behaviors, with only one of 96 models rejected; the rejecters were Red‐throated Pipits (Anthus cervinus). Such differences suggest that the cuckoos might successfully parasitize naïve hosts and become established in North America whether or not their historic host species are widely available. 相似文献
10.