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1.
大兴安岭地区紫貂冬季生境选择的研究   总被引:20,自引:6,他引:14  
姜兆文  徐利 《兽类学报》1998,18(2):112-119
1991~1993年在大兴安岭的呼中和图强区,采用雪地足迹跟踪法研究了紫貂(Marteszi-belina)冬季对取食和休息生境的选择特点,结果表明紫貂喜好植被演替晚期的林型,具体特点如下:(1)喜好中等到高等树冠盖度的乔木林地(P=0.0001)和混合型林地(P=0.02),回避单一树种优势林地和空地。(2)对灌木盖度无选择性(P=0.09),但喜好混合型灌木林地(P=0.03)。(3)取食时喜好下坡位及岸边,休息时选择上坡位(P=0.009),且倒木、大胸径树和树根较多的生境,不选择坡向(P=0.39)。(4)对大树密度(P=0.0001)、落叶松基区面积(P=0.005)、大树胸径(P=0.0001)、落叶松胸径(P=0.0014)、倒木全长(P=0.0006)、倒木直径(P=0.0014)及倒木覆盖面积(P=0.0001)都有明显的正选择性,且休息对生境的选择强于取食。对小树密度取食时喜好中等密度(1.21~1.82棵/m2)林地,而休息时回避高密度区(1.82~3.03棵/m2)。根据上述结果建议在择伐过程中应当保留植被演替晚期的林型和胸径在40cm左右的大树。  相似文献   

2.
大兴安岭地区紫貂的活动节律   总被引:10,自引:1,他引:9  
马建章  徐利 《兽类学报》1999,19(2):95-100
借助无线电遥测技术,对4只紫貂全年的活动节律进行了研究,结果表明,紫貂的活动节律春季和冬季的高峰是在晨昏二个阶段,夏秋二季的活动高峰在白昼。春季总体活动节律与夏季相比有明显差异(F=4.499,df=1,22,23;P=0.045),春季与秋季的活动节律也有差异(F=7.039;df=1,22,23;P=0.015)。其总体平均活动强度,春季活动量最小(17.53%),夏季最高(38.29%),其  相似文献   

3.
紫貂冬季生境的偏好   总被引:22,自引:1,他引:21  
采用无线电跟踪技术和全球定位系统对大兴安岭阿巴河流域紫貂冬季的生境选择进行了研究。结果表明,紫貂偏好成熟林地和老龄林地。(1)紫貂冬季栖息地主要的优势树种是落叶松林,对中等盖度的林地选择性强,而开阔地带和特别高盖度地区。(2)主要栖息中,下坡位,而对上坡位选择性不强。(3)对小树密度,大树密度,乔木胸径,倒木长度,倒木密度,倒木直径等有正选择性。  相似文献   

4.
紫貂春季和夏季生境选择的初步研究   总被引:7,自引:0,他引:7  
张洪海  马建章 《动物学报》2000,46(4):399-406
1994~1996年,在大兴安岭满归林业局北岸林场的阿巴河流域原始林中,采用无线电跟踪技术和全球定位系统(GPS)对紫貂春季和夏季的生境选择进行了研究。结果表明:1)紫貂对盖度为6%~75%的林地选择性强,而对5%以下和76%以上地区选择性较弱;栖息地优势树种为兴安落叶松;(2)主要喜欢中、下坡位;(3)对小树密度、大树密度、乔木胸径(diameter of breast height,DBH)、  相似文献   

5.
根据内蒙古阿巴嗄旗那仁宝力格苏木1979-1997年啮齿动物监测资料,利用变动指数(S),得知布氏田鼠密度的年际动态具有一定的周期性,1989-1997年共捕啮齿动物10种,其中田鼠占88.45%,达乌尔鼠兔占5.37%。总密度(单位面积上啮齿动物的密度之和)、田鼠密度、鼠兔密度间均呈正相关,回归模型为:总密度=0.8806+1.0048(田鼠密度)+0.8779(鼠兔密度(P=0.0001)。田  相似文献   

6.
紫貂冬季食性的分析   总被引:3,自引:2,他引:1  
徐利  王永庆 《兽类学报》1996,16(4):272-277
1991至1998年的三个冬季,在大兴安岭地区共收集紫貂粪样223个.食性分析结果表明,紫貂冬季食物主要为小型哺乳类(54.1%)、植物浆果和种子(32.4%)、鸟类(12.5%)和昆虫(1.0%).在紫貂选择的7种小型哺乳类中,主要以棕背(27.3%)和红背(19.2%)为食,其次为雪兔和冬眠的花鼠。对于鸟类,紫貂主要捕食花尾榛鸡(8.1%),松鸦(0.7%),大山雀(0.5%)和黑啄本鸟等。有2.2%的粪样中含有小型鸟的卵壳、紫貂的植物性食物主要为越桔浆果(20.8%)和偃松种籽(8.8%)。昆虫中只有蚂蚁在紫貂食性中出现(1.0%).紫貂冬季食物构成没有年度间差异(P>0.05)。通过捕食迹,我们还发现紫貂捕食黑嘴松鸡。虽然红背的捕获率(79.4%)高于棕背(2.9%),但食性分析结果却相反,说明紫貂更喜欢捕捉身体较大的鼠类。有较强气味的中虽有一定的数量,但在紫貂冬季食物中未出现过。  相似文献   

7.
内蒙古察哈尔丘陵啮齿动物种群数量的波动和演替   总被引:4,自引:1,他引:3  
李仲来  张耀星 《兽类学报》1997,17(2):118-124
根据内蒙古自治区正镶白旗乌宁巴图苏木974-1993年随啮齿动物密度监测资料进行分析,得到如下结果。共捕啮齿动物13种,其中达乌尔黄鼠为优势种(67.85%)、一趾鼠为次优势种(10.16%),长爪沙鼠、布氏田鼠、达乌尔鼠兔为常见种,余为少见种。黄鼠密度与个体数呈正相关(P〈0.0001)、五趾跳鼠与个体数、黄鼠密度呈负相关(P〈0.001)。个体数与黄鼠、五趾跳鼠密度的回归模型为:(个体数)=1  相似文献   

8.
应用底物膜技术检测130例正常精液,精子顶体酶活性百分率的正常值下限为57%。459例不孕症病人精液分析,无精症25例,其余434例中75%精子顶体酶活性正常。实验表明精子密度对数值与顶体酶活性百分率之间有正相关,r=0.84(P<0.01),回归方程为顶体酶活性百分率y=48.43%+(8.9%)(log精子计数)。活动精子百分率与顶体酶活性之间有密切正相关,r=0.967,(P<0.01),顶体酶活性y=38.6%+0、36x%。前向活跃直线运动精子百分率与顶体酶活性之间也有密切相关.r=0.96,(P<0.01),顶体酶活性y=34.21%+0.61x%。  相似文献   

9.
安西荒漠植物群落和优势种的分布与环境的关系   总被引:6,自引:0,他引:6  
应用排序(DCA)和回归分析方法对安西砾石戈壁荒漠植物群落及优势种的分布与环境的关系进行了研究。结果表明,该区群落的盖度(C)和密度(D)均与年降水量(R)有密切关系,而群落的种类丰富度(N)则与土壤含盐量(S)相关,其回归关系式为:C=0.051968163e0.040786821R(R=0.95,P<0.01),D=0.27147913e0.052741829R(R=0.96,P<0.01),N=13.7748-6.477303lg1000S(R=0.83,P<0.01)。即:年降水量是决定戈壁荒漠植物群落盖度和密度的主要因素,土壤含盐量则与群落种类丰富度的关系尤为突出。优势种的抗旱性顺序是:红砂(Reaumuriasongorica((Pal.)Maxim.)>泡泡刺(NitrariasphaerocarpaMaxim.)>黑柴(SympegmaregeliBge.)>珍珠(SalsolapaserinaBge.)>膜果麻黄(EphedraprzewalskiStapf.),而耐盐性顺序是:珍珠>红砂>黑柴>泡泡刺>膜果麻黄  相似文献   

10.
贵州草海斑头雁的冬季食性分析   总被引:7,自引:0,他引:7  
在贵州草海越多的斑头雁粪便中共检出36种植物,其中天然植物28种,栽培作物种,禾本科植物是斑头雁主要食物,在其粪便中的平均检出率是65.0%,白花三叶草平均为16.4%,莎草科植物为9.7%,农作物仅占5.6%,其他的材料为3.3%,随着月份的不同,六种主要植物及栽培作物在斑头雁粪便中变化非常明显(P〈0.0001,df1=4,df2=70)。  相似文献   

11.
12.
Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.  相似文献   

13.
On the diversity of the Cladocera in the tropics   总被引:20,自引:13,他引:7  
The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.  相似文献   

14.
Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.
Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.
  相似文献   

15.
16.
Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m2 s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.  相似文献   

17.
The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.  相似文献   

18.
Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan  相似文献   

19.
When constructing predictors on the basis of the linear model of time series of various indicators often the question arises on the dependence of forecasting accuracy and the changing prediction horizon. The dependency of the quadratic risk of the classical predictor and the time horizon is considered.  相似文献   

20.
基于吴征镒将中国全部种子植物3238个属的分布区划分为15个大类型和34个变型的基础上,简要地讨论了中国植物区系与其它地区区系的联系,以及它在被子植物起源方面的作用。主要论点如下:(1)与热带亚洲区系的联系。这种联系主要通过第7类型(热带亚洲分布)及其5个变型来体现的。本文列举了10个科,龙脑香料、狭义隐翼科、交让木科、五隔草科、五列木科、肉实树科、心翼果科、八宝树科、兰花蕉科和四数木科,来说明这  相似文献   

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