埃塞俄比亚Senkele Swayne保护区斯韦恩麇羚的种群现状与结构

于2005年10月至2006年4月调查了埃塞俄比亚森可勒斯韦恩麇羚保护区旱季和湿季斯韦恩麋羚（Alcelaphus buselaphus swaynei）的种群现状与结构。根据植被类型、道路和沟谷,将研究区划分为5个区域,并且调查了保护区外的一块休耕农地。利用全部计数法计数了每个区域内的斯韦恩麋羚,在28km^2的区域内共统计到283只（湿季）和351只（旱季）麋羚,湿季和旱季的糜羚数量变化显著,其季节间差异是由旱季的出生高峰造成的。斯韦恩糜羚种群中雌性个体占42．7％、雄性占36．0％、幼羚占21．3％。某些区域的麋羚数量要高于其它区域,且无论湿季或旱季斯韦恩麋羚多集中在狼尾草高草地中。斯韦恩麋羚的种群结构随季节而变化,其大集群经常出现在湿季而旱季集群较小。斯韦恩麇羚的种群动态因保护程度的不同在不同时期呈不规则性变化     

尚勇保护区亚洲象种群数量动态、种群结构及季节分布格局

在2006 年6 月至2007 年9 月,通过种群个体识别、社区监测网络、样线调查和村寨访问等方法对尚勇保护区亚洲象的种群动态和季节性分布格局进行研究。结果显示:目前在尚勇保护区的亚洲象种群数量约为68头;拍摄到亚洲象共计347 头次,通过个体识别方法识别出亚洲象53 头,其中幼体、青少年体、亚成体和成体数量及所占比例分别为:3 (5.66%)、11 (20.75% )、15 (28.30% )、24 (45.28% ),在成体中雄性只有两头,成年象的雌雄性比为11∶ 1,高于已知国内外的其他区域。从1992 年至2007 年10 月,至少有32 头亚洲象死亡,其中确认死于猎杀的有7 头,保护区的核心区野牛河、金宝河一带是盗猎亚洲象最严重的地区。严重的盗猎和不断减少的栖息地对当地的亚洲象种群产生了巨大的威胁,也加剧了当地的人象冲突。在雨季和旱季,亚洲象各有五个核心活动区域,食物是导致雨季和旱季分布格局不同的主要因素。     

广西恩城保护区黑叶猴种群数量和保护现状

黑叶猴是栖息于喀斯特石山地区的珍稀濒危灵长类动物,由于非法捕杀和栖息地丧失,种群数量急剧减少。2017年10-12月,我们采用样方法调查恩城国家级自然保护区及其周边地区黑叶猴的种群分布、数量及保护现状,分析其致危因素,为制定有效管理行动计划提供理论依据。本次调查共记录到黑叶猴夜宿地89处,其中有43处夜宿地下方有新鲜排泄物。结合本次调查和访问,确定黑叶猴的种群数量为18群100~105只,包括1只全白化黑叶猴成年雌性个体;其中11群分布在保护区内,7群分布在保护区外。猴群由3~12只个体组成。栖息地破碎化和退化是威胁恩城保护区黑叶猴种群生存的主要因素。     

大雾岭保护区野猪种群数量、结构及繁殖习性的初步研究

野猪 ( Susscrofa)是重要的资源兽类之一 ,几乎广布于我国各地 ,国外见于欧洲、非洲和亚洲。至今已记录的亚种有 2 3个 ,我国 6个 [1～ 3] ,由于大量捕杀和栖息地破坏 ,其数量下降很快 ,不少地方已很难见到 [1,4 ] 。广东已将野猪列为省重点保护动物。开展野猪生态学的研究 ,可为野猪资源的保护和利用提供科学依据。近年来 ,国外对野猪的种群生态学的研究十分活跃 ,内容广而深入 [5～ 12 ] ,而国内迄今只有几篇综述性的报道 [13～ 16 ] ,仅有高中信等对小兴安岭地区野猪冬季卧息地选择进行了较为细致的研究 [4 ] 。笔者于 1 996年 5月至 1 …     

黄山松种群结构与动态研究

以“空间代替时间”的方法,以种群径级结构代替年龄结构,采用静态生命表和生存分析的方法,探讨了天柱山国家森林公园黄山松种群结构和动态规律。结果表明,随海拔升高,黄山松种群密度增大,径级分布范围减小,种群存活曲线由Deevey-Ⅱ型之间过渡到Deevey—Ⅰ型,种群由稳定型过渡为增长型。表明由低海拔向高海拔,黄山松种群处于不同的演替和发展阶段。     

沙地云杉种群结构与动态的研究

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。     

陕南马尾松种群结构与动态的初步研究

马尾松是陕西南森林群落演替过程中的先锋树种,但在山坡中上部及山脊等立地条件较差的生境中能够。其稳定性表在两个方面：（１）时间上－年龄结构呈倒Ｊ型,即拥有众多的幼苗幼树和少量上层木;（２）空间上－个体分布格局,即同龄个体所组成的斑块间的交替更新;这种稳定性属于地域性特征。种群结构动态变化的主要动力是种内竞争。     

红松的种群结构与动态过程

一、前言种群结构的若干文献,已从不同侧面证明了红松(Pinus koraiensis)种群的随机分布格局和多世代异龄结构特征。Putman 指出:群落结构和功能的体现,很大程度上是由子那些影响其种群动态因子作用的结果。因此通过种群结构的研究,进一步探讨与之相联的过程性质,以及结构与过程的内在联系和作用形式将是可行的。正如群落和系统的结构是功能的保证一样,种群的结构也是其动态与过程的基础和保证,同时它又相应地制约着由其组成的群落或系统的特征。     

贵州草海保护区钳嘴鹳种群动态

新分布种对当地生态系统的影响具有不确定性,掌握其种群动态对于制定相应的管理策略具有重要意义。钳嘴鹳(Anastomus oscitans)为我国新分布种,目前已扩散至云南、贵州、广西、四川等省(自治区),但对其种群数量及变化规律尚缺乏了解。2013年1月至2014年12月,采用夜栖地直接计数法对贵州省草海自然保护区钳嘴鹳的种群数量进行了监测。结果表明,1)钳嘴鹳主要在夏季出现,冬季数量较少,表现出明显的季节性差异(P0.001)。2)钳嘴鹳种群数量呈现逐年增加趋势,2013年的度夏期(5~10月份)平均数量为200.6只(SD=94.6,n=24),最高数量为427只;2014年的度夏期平均数量增长到356.0只(SD=180.3,n=25),最高数量为602只。3)钳嘴鹳为树上夜栖物种,调查中共发现5处夜栖地,其中位于保护区东南部的簸箕湾是主要夜栖地,在2013、2014年的统计中,该地钳嘴鹳分别占总数量的56.46%和63.53%。由于钳嘴鹳的游荡性较强,建议在其主要分布区开展同步监测,从而整体掌握其种群变化和分布情况。     

濒危植物连香树种群结构与动态研究

以空间代替时间的方法调查了喇叭河自然保护区和宝兴县两个地区连香树种群的结构.绘制大小结构图,编制静态生命表,绘制存活曲线、消失率曲线和死亡率曲线,并进行种群动态谱分析.结果表明:两个地区连香树种群幼苗个体比例都比较大,但死亡率很高;存活曲线介于Deevey Ⅰ型和DeeveyⅡ型之间;消失率和死亡率曲线变化趋势一致;种群动态过程存在周期性,种群数量动态不仅受基波的影响,而且还显示出了小周期的波动.     

Population structure, genetic variation and morphological diversity in indigenous sheep of Ethiopia

We investigated genetic and morphological diversity and population structure of 14 traditional sheep populations originating from four ecological zones in Ethiopia (sub-alpine, wet highland, sub-humid lowland and arid lowland). All animals (n = 672) were genotyped for 17 microsatellite markers and scored for 12 morphological characters. The sheep were initially classified as fat-tailed (11 populations), thin-tailed (one population) and fat-rumped sheep (two populations). These classifications are thought to correspond to three consecutive introduction events of sheep from the Near-East into East Africa. For the 14 populations, allelic richness ranged from 5.87 to 7.51 and expected heterozygosity (H(E)) from 0.66 to 0.75. Genetic differentiations (F(ST) values) between all pairs of populations, except between sub-alpine populations, were significantly different from zero (P < 0.001). Cluster analysis of morphological characters and a dendrogram constructed from genetic distances were broadly consistent with the classification into fat-tailed, thin-tailed and fat-rumped sheep. Bayesian cluster analysis using microsatellite markers indicated that there has been further genetic differentiation after the initial introduction of sheep into Ethiopia. Investigation of factors associated with genetic variation showed that an isolation-by-distance model, independently of other factors, explained most of the observed genetic variation. We also obtained a strong indication of adaptive divergence in morphological characters, patterns of morphological variation being highly associated with ecology even when the effect of neutral genetic divergence (F(ST)) was parcelled out in partial Mantel tests. Using a combination of F(ST) values, Bayesian clustering analysis and morphological divergence, we propose a classification of Ethiopian sheep into six breed groups and nine breeds.     

Population status and structure of mountain nyala in the Bale Mountains National Park, Ethiopia

The study on the population status and structure of mountain nyala (Tragelaphus buxtoni) was carried out in the Bale Mountains National Park, Ethiopia during the wet and dry seasons of 2000/2001. Total counts were carried out in an area of 13.1 km². The count ranged between 682 and 732 individuals. Females comprised 62.9% while males 27.4%. The calf ratio was 9.7%. The group structure of the animals varied with season. Large herds were frequently observed during the wet season and smaller groups during the dry season. Group size changed seasonally. In both seasons, 7–12 individuals were the frequent group size formation. The maximum group (62) was observed during the wet season. The population trend of the animal from 1975 to 1990 indicated a recovery and increase. But between 1990 and 1995 the population showed a continuous and steep decline. However, between 1995 and 2000 the population trend showed a better condition when compared with the previous years.     

Population trends,distribution and conservation status of semi-domesticated reindeer (Rangifer tarandus) in China

The reindeer (Rangifer tarandus tarandus) is listed as a species of “least concern” on the Red List of Threatened Species of the World Conservation Union (IUCN). It is distributed in the northern part of China and semi-domesticated in the region. Here we present a comparison of the historical and current distribution and numbers of reindeer in China, as well as an assessment of the factors limiting population growth. Based on this information we explore potential protective measures for reindeer in China.The reindeer has been herded extensively by the Ewenki people, the only people to do so in China. Reindeer in China originated from the Wenduosenlin tundra highlands of Siberia. Capable of migrating more than 3000 km/year, the reindeer moved from the highlands to the Weitimu river during the 16th century and on to the Northeast area of China in 1654. Since 1957, 600 reindeer have settled in Qiqian in Inner Mongolia, and from 1965 more than 900 reindeer migrated from there to Mangui. In response to frequent flooding and a fluctuating reindeer population in the Mangui region, in 2003 the Ewenki people and more than 260 reindeer translocated from there to Aoluguya.Currently, eight meta-populations of reindeer comprising 773 individuals inhabit in the Arctic region of China. The reindeer population peaked in the 1970s at more than 1080 animals, but declined markedly from 1998 onwards mainly as a result of inbreeding, poaching, predation and tourism. The Chinese government's interest in wildlife protection is increasing, as evidenced by the introduction of wildlife protection laws and regulations, the importation of new reindeer varieties from Russia and the joining of the Association of World Reindeer Herders. However, natural reserves and national parks have still not been established within the reindeer's range in China to conserve this fragile population.     

Population structure and dynamics of Pinus taiwanensis Hayata at Songyang county,Zhejiang Province,China

Pinus taiwanensis is a widely distributed species in the southeastern China (Zhejiang, Anhui, Hubei, Human, Jiangxi, Fujian, Taiwan provinces) at an elevation of 700–2000 m. This pine is a pioneer in forest succession and is often used as a species for afforestation in this region at an elevation above 700 m. This study was carried out at Guanshanyuan, Zhejiang province, at a latitude of N 28° 18, a longitude of E 119° 16 and an altitude of 800–1502 m above sea level. On the basis of a census of all individuals of Pinus taiwanensis at different successional stages and various habitats, age structure, spatial pattern, density, biomass of population and their dynamics were described. Considering the population dynamics throughout the successional process, three phases could be recognized. Until about 9–10 years after Pinus taiwanensis invaded the stands, the density of population was increased by the recruitments along with increase of the mean tree weight and population biomass (phase I). Thereafter, the population was in full density state, the biomass of population and the mean tree weight increased exponentially, while the density was decreased drastically by the self-thinning and the invasion of other broad-leaved trees (phase II). The –3/2 power law of natural thinning was applicable to the populations in this phase. When the broad-leaved trees reached the canopy, although the mean tree weight increased slowly, the density and biomass of Pinus taiwanensis population decreased gradually (phase III) until the population senesced and retreated from the successional series completely. The population dynamics of Pinus taiwanensis during the successional process was in common with pioneer species in forest succession. At some special habitats such as rocky steep slopes and ridges, however, Pinus taiwanensis population could form such an edaphic climax community that the population density, biomass and the mean tree weight in phase III could be in a stable state for very long period.     

Evolution of body size in the genus Damaliscus: a comparison with hartebeest Alcelaphus spp.

In species with low levels of sexual size dimorphism, it may be relatively easy to detect the role of natural selection in the evolution of body size. Habitat primary production (HPP) appears to be a key factor in the divergence of size in the hartebeest clade ( Alcelaphus spp.), such that subspecies in less productive savannahs are smaller than those in richer ones. Here I test whether a similar pattern exists within the genus Damaliscus (topi and their allies). Basal skull length was used as a surrogate of body size and measured in the seven allopatric subspecies of Damaliscus . Means for each subspecies and sex were regressed against climatic factors as surrogates of HPP. Variation in skull length across Damaliscus taxa was less than in hartebeest. Two clusters were present in both sexes and corresponded to the distinction between the species, Damaliscus dorcas and Damaliscus lunatus . This may reflect differences in productivity between edaphic grasslands, occupied by all D. lunatus , and dry grasslands, occupied by D. dorcas . Mean annual rainfall was the best predictor of body size in males and showed a non-significant positive tendency in females. After accounting for phylogenetic effects, these correlations were both non-significant. Edaphic grasslands might be less dependent on precipitation for primary production because the impeded drainage of their soil prolongs water availability after the end of the rains. Furthermore, they are probably more consistent in productivity across African regions than secondary grasslands and savannah woodlands, which rely on rainfall for grass growth. These properties of edaphic grasslands may explain why size in Damaliscus appears to be less sensitive to variation in rainfall and less variable across subspecies than in Alcelaphus .     

Population structure and dynamics of Pinus massoniana Lamb. on mount Jinyun,Sichuan, China

Masson Pine (Pinus massoniana Lamb.) is a pioneer in forest succession in the subtropics of East Asia. However, the species persits, though with decreasing abundance, throughout the various successional phases. Agestructure, spatial pattern, density, population biomass, and their dynamics are described for a population in Sichuan, China, on the basis of a census of all individuals in the population while substituting space with time. In the course of succession, the population density increases and its rate of growth decreases until self-thinning starts; during the phase of self-thinning density decrease and continues to decrease even afterwards, but the rate of growth increase markedly after self-thinning has stopped. The development of population biomass (Bp) during the early succession from shrub-grassland to the early stages of mixed pine and broad-leaved forest can be described by a logistic equation. Later, Bp decrease rapidly. These changes are governed partly by inherent biological features of P. massoniana and partly by the invasion, establishment and development of shade-tolerant evergreen broad-leaved trees. Both self- and alien-thinning occur. Soil conditions affect the rates of these processes.     

Population development of the mosquitofish,Gambusia affinis,in rice fields

Synopsis Development of mosquitofish,Gambusia affinis, stocks in rice fields following stocking for mosquito control is poorly understood and highly variable. To characterize population development and explain observed variability, size distributions and total numbers of mosquitofish stocks were followed from stocking through the end of the summer rice season in several experimental rice paddies. Instead of the highly variable, logistic growth implied by previous studies in which only adult fish were sampled, we observed a consistent development of size structure between years, with some variability in specific demographic processes. Population development consists of: (1) an initial peak in numbers due to a pulse of recruitment, (2) a period of low recruitment and constant or declining numbers, and (3) a second peak caused by a second pulse of recruitment. Timing of the initial peak appears to depend on rice height. Differences in the rate of decline following the peak are apparently due to different mortality rates. The second peak in reproduction is probably due to a second parturition by stocked females, possibly followed by first reproduction by young born earlier. Since population development in rice fields following stocking in the spring is similar to development of natural populations in temperate regions in which there is no reproduction during the winter, results obtained here are relevant to natural as well as artificially stocked systems.     

Population size, pollination and reproductive success in two endangered Genista species

Habitat fragmentation often leads to small and isolated plant populations as well as decreased habitat quality. These processes can fundamentally disrupt the interactions between plants and pollinators and decrease reproductive success. This concerns especially self-incompatible, non-clonal species that depend on pollination for successful reproduction.In two rare and endangered heathland plant species, Genista anglica and G. pilosa, we examined pollination and reproduction in relation to population size. Eight populations of G. anglica and ten populations of G. pilosa were surveyed in the vicinity of Bremen, NW-Germany. We counted the visits of pollinators (honeybees, bumblebees, and other insects) and determined the reproductive output of the observed shoots.Contrary to our expectation to find increased pollinator visitation rates in larger populations of both Genista species, the number of flower-visiting insects was unrelated to the number of flowering shoots. Increasing shoot length had a positive and increasing temperature a negative impact on the number of visiting honeybees and bumblebees. Despite the general absence of population size effects on pollinator numbers, the number of fruits and seeds in G. anglica increased with increasing population size. Fruit and seed set in G. pilosa were negatively related to the number of ‘other insects’. Our field observations showed that larger populations of both Genista species flowered earlier than smaller populations and much earlier than reported in the literature. Flowering in large populations therefore tends to coincide less well with pollinator abundance, and this may cause a disruption of the temporal coincidence between flowering phenology and pollinator activity.     

Population structure and movement patterns within an isolated and endangered population of the moth Dysauxes ancilla L. (Lepidoptera, Ctenuchidae): implications for conservation

Population structure and movement patterns were studied in a geographically isolated and endangered Swedish population of the moth Dysauxes ancilla. Mark-recapture experiments were conducted between 1993–97 and observations made of adult behaviour between 1993–99. The population size was estimated to be 2356 individuals and the average male residence time 2.6 days. Adults of D. ancilla were sedentary and all movements occurred within the breeding area, despite searches up to 0.5 km away. Mean (± S.D.) distance between two successive captures in males was 43 ± 36 m and the longest single move was 144 m. The moths showed a behavioural reluctance to enter heavily grazed meadows or dense vegetation at the edges of the breeding habitat. Since there are no suitable habitats in the surroundings, conservation efforts should focus on managing the continuity of the current breeding area. Further, the restoration of a former breeding habitat situated 1 km to the north should be considered as well as establishing connections with the extant population.     

Population ecology of an afro-tropical savanna herb,Lapeirousia rivularis,in Zambia

Detailed demographic studies of herbaceuos plants in afro-tropicalsavannas are extremely rare in published literature. I studied phenology andpopulation dynamics of a perennial herb, Lapeirousiarivularis Wanntorp, at a savanna site in Zambia over a 4-yearperiod, from 1997 to 2001, using enumeration techniques in permanent andtemporary quadrants. The age of the plants was accurately determined frompersistent annual sheaths that accumulate around the corm throughout the lifeofthe plant while the estimated survivorship of the 1998 cohort was developedfroma mathematical model based on the observed mortality of the cohort over a3-yearperiod.L. rivularis completed its annual phenological cycle in asingle rainy season. Plants sprouted from perennating corms in early December,flowered, fruited and dispersed seeds by end of January. Seeds germinatedimmediately after dispersal and seedlings produced small corms before aerialparts died early in the dry season. L. rivularis has twomorphs: a vegetative morph and a reproductive morph; the latter bears severalleaves and flower stalks. In the vegetative morph, the corm is renewed annuallywhile the corms of the reproductive morph did not appear to be renewed. Insteadcorms grew larger and produced lateral daughter corms that became independentramets the following rainy season.Most L. rivularis plants reached reproductive maturitywhen they were 6–10 years old. Reproductive success, seedlingestablishment and recruitment varied from year to year in the grassland plotperhaps because of fluctuations in weather conditions and heavy episodic insectherbivory. The survivorship curve of L. rivularis wascharacteristically concave due to high juvenile mortality (0.2–0.5) andvery low adult mortality (0.03). Although about 3% of the plants live to be upto 30–35 years, the mean age of the population in 2001 was 6.4 yearsbecause of the predominance of juvenile plants. The production of a protectivesheath at the end of the rainy season and the accumulation of old sheathsaroundthe fleshy corm are apparent adaptations against desiccation during the longdryseason drought when the topsoil remains below wilting point. The high juvenilemortality during the dry season is probably caused by inadequate protection bythe few sheaths around the corm against desiccation.Population dynamics in L. rivularis were caused byvariable annual recruitment and high juvenile mortality. Population densitydoubled in 1999 due to good fruiting success in the previous season that wasassociated with good weather conditions and negligible herbivory. Althoughcultivation had a significant negative effect on the population of L.rivularis, it increased consistency in fruiting success andproduction of fruits per plant, presumably because of improvement insoil-moisture status, reduction in plant competition and by providing temporalescape from insect herbivory through delayed flowering. The phenology and lifehistory of L. rivularis exhibit adaptations to a savannaenvironment that is characterized by disturbance and stress caused by seasonaldrought, fire, episodic herbivory and cultivation.