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1.
中国驼鹿种群数量及分布现状的研究   总被引:6,自引:2,他引:4  
1985一1987年间,作者在中国东北大、小兴安岭林区,根据三阶抽样的原理,选择1 6块样地,设置并调查202条样带,长2476.6km,遇见309条驼鹿足迹链。由此,明确了驼鹿在中国的分布区域并确定总栖息面积为1 9万多km2 .平均分布密度为0.0519头/km2,种群数量为9955士397头(a=0.2 ),其种群下降率年平均逃6.3 %,且呈继续下降趋势, 亟待保护。  相似文献   

2.
佛坪大熊猫的分布与数量   总被引:13,自引:0,他引:13  
雍严格  张坚 《兽类学报》1993,13(4):245-250
作者于1990年11—12月对佛坪自然保护区境内大熊猫的分布和数量进行了调查。结果得知在区内293平方公里中共有大熊猫64只,平均密度为0.22只/平方公里。与1974、1983、1988年3次的调查结果比较,表明佛坪大熊猫现有种群基本稳定。  相似文献   

3.
滇金丝猴(Rhinopithecus bieti)属于世界珍稀灵长类动物,对它的研究报道仅限于分类地位(彭鸿绶等,1962;彭燕章等,1985;陈服官等,1981)、形态解剖(陈宜峰,1981;彭燕章等,1983;张耀平等,1983)、地理分布及生活习性(李致祥等,1981;木文伟等,1982)等。其分布、数量以及进化地位、生态学等方面的资料甚少。1985年笔者在白马雪山自然保护区对滇金丝猴的数量、分布及种群结构进行了观察。  相似文献   

4.
This is the second paper dealing with techniques necessary to the population estimation of the Cryptomeria red mite feeding on a coniferous Cryptomeria tree, with the final object of determining the absolute population. Results are as follows:
  1. The population can be defined as the whole of mites existing on branches with foliage younger than two years old, because more than 95% of individuals are always there.
  2. Optimal sampling unit varies according to mite population. Unless a fixed unit is necessary, seasonal placement of units is recommended.
  3. Since significant variance is associated with crown levels, representative sampling from each level is designed. These calculation should be based on the data transformed to logarithms, as the relation between mean and variance suggests that the population data are of contagious distribution.
  4. A trial to calculate the total length of branches for each age, which is needed for the conversion to absolute population, is described.
  相似文献   

5.
银杉种群的空间分布格局   总被引:49,自引:0,他引:49  
银杉(CathayaargyrophyllaChunetKuang)种群的空间分布格局受银杉种群本身的生物学特性、种群的年龄和更新方式等及群落内小环境的共同影响。在老龄种群内,多表现为集群分布;在较年轻的种群内,多为随机分布。气候和立地条件基本一致时,群落内岩石的覆盖与土壤蚀形成的小环境。  相似文献   

6.
Of the gibbons in China,Hylobates hoolock, H. lar, andH. concolor leucogenys are distributed only in Yunnan Province, whileH. c. concolor occurs limitedly in Yunnan Province and Hainan Island. During the periods from February to November 1984, and March to August 1985, the authors undertook surveys of the population and distribution of gibbons in 56 counties of 10 prefectures in Yunnan Province, and obtained the first reliable population and distribution data on the gibbons of this Province. The findings serve to fill an important blank in gibbon research in Yunnan and should pave the way for further research in the future.  相似文献   

7.
The plant-to-plant movement of insects in one of the factors determining the distribution of individuals in insect populations. In this report the movement of barley aphids was analyzed by a statistical model. The model is represented as the convolution of three probability functions:
  1. The probability that s individuals are found on a plant at time t0:Q(s);
  2. The probability that i individuals leave the plant and remain on the ground from time t0 to t1:sCipiqs−i and p+q=1, where p and q are the proportions of individuals which do not leave a plant and which leave it once or more, respectively;
  3. The probability that j individuals climb a plant between time t0 to t1 and stay there at time t1:e−λλj!, where λ is the mean of the individuals.
The probability that l individuals are located on a plant at time t1 is represented by the following equation It was shown by simple experiments that the experimental populations were well fitted to the model.  相似文献   

8.
The population activities of golden monkeys (Rhinopithecus roxellana) in the Xiaoshennongjia of Badong county,Hubei Province had been surveyed by consecutively tracing and grossly counting from 0ct.2000 to June 2002.The result indicated the anmount the golden monkey that iuhabit in here about 600-800 individuals.They moved clockwise in a circular track.236 golden monkeys of 2 groups had recorded by video camera during survey in Apr.2001,among them there were 59.05% adult and 40.95% of underage,the rate was 1:0.9,the sex ratio of adult was 1:1.38 (male:female).117 individuals of three different groups were recorded in random in 2002,among them were 56.41% of adult and 43.59% underage,the rate was 1:0.67,the sex ratio of adult was 1:1.2.The young were hem from the beginning the month of March.  相似文献   

9.
The period of Cenozoic Himalayan orogeny was the developmental stage of the marginal seas and islands adjacent to the western Pacific. In the study, the molecular divergence dating between the northern and southern groups by fossil calibration was approximately 10.9 Myr, which was earlier than the time of the formation of Taiwan Island. Statistical-Dispersal Vicariance Analysis (S-DIVA) suggested that mantis shrimp of the China seas originated from two different ancestral regions (i.e., the Yellow Sea and South China Sea). However, the fluctuation of the Taiwan Strait in the late glacial period further influenced the phylogeographic structure of the mantis shrimp. In addition, the opposite ocean currents of the northern and southern seas of China, driving the planktonic larvae of marine species in opposite directions in the reproductive season, further accelerated their genetic divergence. In contrast, there were weak differences among the three northern seas due to their sharing one common ancestral region and then facing the dispersal event in the Cenozoic era and later sudden population expansion in the late Quaternary interglacial (54–75 ka). In conclusion, geological and climatic changes in past geological periods have greatly influenced the geographical distribution, dispersal and genetic divergence of the mantis shrimp.  相似文献   

10.
Shiyomi (1967a and b) proposed two models which describe the reproduction and the plant-to-plant movement of aphids. For the explanation of the whole process of development of population of aphids, the above two models were incorporated into a new model (called Model C). This model is superior in the following points to the negative binomial model:
  1. Model C has 7 parameters and gives a fuller explanation compared with the negative binomial model which has 2 parameters.
  2. Model C describes the structure of population at any stage of its development, while the negative binomial model describes that of a well developed stage of population.
  相似文献   

11.
云贵高原黑颈鹤的种群数量和分布   总被引:8,自引:1,他引:7  
云贵高原有黑颈鹤的两个越冬区:(1)云南西部;(2)云南东北部和贵州西北部。这两个地区的黑颈鹤数量占全球种群的1/4至1/3。国际鹤类基金会与云南省林业厅于2001/2002年冬季在云贵高原联合对黑颈鹤进行了一次同步计数,本次调查覆盖了17个已知或潜在的黑颈鹤越冬地点,其中15个地点有黑颈鹤分布。在2002年1月18日和19日,分别记录到3261和3182只黑颈鹤。本调查还统计了灰鹤、斑头雁和赤麻鸭,数量分别为:灰鹤804和1158只;斑头雁1759和2978只;赤麻鸭3442和5444只。与1991/1992年冬季进行的调查结果相比,黑颈鹤在这一地区的数量增加了90%以上。  相似文献   

12.
Eleutharrhena macrocarpa is a grade protected wild plant,also known as one of the tiny population. Through consulting relevant literature and records, access specimen investigation and field survey, A survey on geographical distribution、community and population status of it was conducted. The results show that: (1) there are a counter of 19 distribution points of Emacrocarpa, since 1910, the first time it was found in China; (2) E. macrocarpa is discontinuously distributed in the tropical rainforest regions of the south, southeast and southwest of Yunnan and Napo in Guangxi. Due to its habitat were severely damaged, 9 of the original record distribution points were disappeared, the number of existing distribution points which was reliable reduce to 10; (3) According to the reliable survey, the number of it just is about 40 strains, and we did not see its seedlings. it show that its natural regeneration is difficulty. Based on the results of the survey, discuss its endangered reasons, and provides the theoretical basis to protect them effectively.  相似文献   

13.
Annuals represent a significant component of the vegetation of coastal salt marshes and sand dunes. From many points of view, the two habitats might appear to have little in common. Yet both are characterized by episodes of low water potential, marked spatial and temporal heterogeneity and a zonation which, within certain limits, reflects successional change.There are also similarities of distribution. Annuals are dominant usually in the pioneer stages; the Salicornia-dominated low marsh areas are perhaps analogues with strandline ephemeral populations (e.g. Cakile maritima) on the fore-dunes. In mature stages, annuals are associated with small gaps in the matrix of perennials, at least some of these arising from drought or disturbance. Nevertheless populations can reach very high densities.The most striking contrast is phenological; only summer annuals are found on marshes, whereas winter annuals predominate on dunes (except for the strandline). Similarly there is a difference in species richness. Rather few species of annual are typical of marshes while a great many are found on dunes.Properties of the seed bank, survival, reproduction and population regulation are compared in marsh and dune annuals, with special reference to Cakile, Salicornia, Rhinanthus and Vulpia. Interpretations are suggested which take account of environmental predictability and heterogeneity. Finally, the general applicability of simple mathematical models of these populations in the different coastal habitats is considered.Nomenclature follows Clapham, Tutin & Warburg (1981) except where otherwise stated.  相似文献   

14.
江苏沿海獐种群的现状和栖息地的利用   总被引:14,自引:0,他引:14  
盐城沿海獐分布的北限为射阳和滨海县交界的扁担河口,南限以如东和海安交界的北凌港闸为界。分属射阳、大丰、东台、海安4县,该区域中獐种群已被隔离成几个小种群。现存数量估计为850—1523头。种群的季节波动很大,繁殖前后种群数量相差近一倍。野外种群性比平均为♀:♂=100:77.3。成幼比=1.19:1.00;8月份调查,平均每头母獐育仔1.53头。该分布区獐喜欢选择有斑块状高草相嵌的矮草草滩栖息。盐城地区獐数量因滩涂围垦和开发而急速下降,急需采取有力对策加以保护。  相似文献   

15.
浙江仙居俞坑森林群落优势种群结构与分布格局研究   总被引:21,自引:2,他引:19  
以浙江仙居俞坑森林群落为研究对象,用“空间序列代替时间变化”的方法,对该群落优势种群的结构和动态进行了分析,结果是:各优势种群中常绿阔叶树种的大小级分布图的形状基本相似,种群存活曲线均表现为极显著的线性关系,种群的年龄结构为稳定型。地树种拟赤杨的年龄结构为衰退型。甜槠、青冈栎、红楠种群的分布格局均呈集群分布,木荷、虎皮楠种群的分布格局多为随机分布,拟赤杨呈随机分布或均匀分布。甜槠种群的幼苗、幼树的  相似文献   

16.
Several parameters of genetic and anthropological interest are commonly estimated in the analysis of the surnames' distribution in human populations. Among these parameters, the most important for population structure is unbiased Isonymy, equivalent to 4 times the value of Fst, the random component of inbreeding in a group. Fisher's α estimates the wealth of surnames in a group, and Karlin-McGregorv is considered proportional to migration rates. Recently, other parameters like Entropy and Redundance of the surname's distribution were introduced in the analysis and estimated. In the present work, the parameters obtained through isonymy analysis of 759,500 telephone users in 379 Communes of Sicily are correlated with variables such as sample size, population size and density, and number of surnames in the Commune. In Sicily, the parameters or their logarithm are Gammadistributed. It is observed that the number of surnames is strongly correlated with most parameters or with their logarithm, and that it is in turn strongly correlated with sample size.  相似文献   

17.
沙地云杉种群结构与动态的研究   总被引:25,自引:5,他引:20  
本文用种群大小结构代替年龄结构研究了沙地云杉种群的大小结构、分布格局和动态规律。结果表明,样地1、2、3、5的沙地云杉种群属于增长型,样地4的沙地云杉种群为稳定型,将样地1、2、3作为一块样地,其分布格局为集群型,但从幼树到大树,则由集群分布变为随机分布。  相似文献   

18.
渤海是黄渤海江豚种群的重要分布区,但是有关该区域江豚的种群数量的资料极其匮乏。2015年至2016年,采用截线抽样法在渤海水域开展了6个航次的目视调查,收集了渤海江豚的分布数据,首次评估了区域内的江豚种群数量,为制定有效的渤海江豚种群生态保护策略提供了基础资料。调查结果显示,在2015年8月、2016年5~7月、9月和11月进行的6个调查航次共计8972 km的有效航程中,发现江豚87次、136头次。江豚在渤海各海湾和中部水域都可观察到;14:00-18:00时段、离岸15~35km范围内较易观察到江豚;黄河口外、秦皇岛东北侧老龙口和莱州外沿岸河口水域,江豚出现频次较多。各季节中,以5月在黄河口外20~40km范围内发现江豚的频次和数量最多。采用Distance 7.0软件估算渤海江豚种群数量,其中探测概率分别取值0.399、0.85和1时,渤海江豚种群数量估算值分别为7883头(CV=0.21)、3701头(CV=0.21)和3124头(CV=0.21),对应的种群密度分别为1.441头/km2、0.066头/km2和0.056头/km2,均低于已报道的南黄海和日本海江豚种群相应值。受海上天气、调查条件和经验所限,本文估值可能存在偏差,但限于渤海江豚历史资料缺乏的现状,本文的结果对于认识渤海江豚的种群状况仍具有重要参考意义。  相似文献   

19.
普氏原羚的分布和种群数量调查   总被引:9,自引:1,他引:8  
2003 年8 ~9 月,对青海省境内普氏原羚的分布和种群数量进行了专项调查。调查结果表明,普氏原羚现存7 个种群,累计数量为602 只;其中塔勒旋果种群属首次报道。与以往报道相比,目前元者和鸟岛种群数量呈下降趋势;海晏—刚察种群数量增长明显;湖东—克图种群数量有所回升,但仍没有达到20 世纪80 年代中期时的种群数量。普氏原羚种群数量变化与栖息地质量及人为干扰程度有密切相关。本次调查显示,普氏原羚现存栖息地呈不连续的间断分布,随着区域经济开发力度的加大,其栖息地在不断缩减、生存环境质量仍在继续恶化。  相似文献   

20.
广东省原鸡种群数量、分布及栖息地现状的初步调查   总被引:3,自引:1,他引:2  
广东原鸡栖息地分布在徐闻,雷州,信宜,高州,阳春5个县(市),为孤立的三块,呈岛屿状分布,总面积2501.62km^2,总体数量680-750只,原鸡数量最多,面积最大的一块栖息地是由信宜,高州,阳春3块小栖息地组合而成,成为广东原鸡的主要栖息和分布地。  相似文献   

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