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1.
Species richness, taxonomic diversity, and qualitative composition of the butterfly fauna (Lepidoptera, Diurna) are discussed in the light of data on the altitudinal zonality of local faunas in the southern Far East and Transbaikalia. It is shown that qualitative elevation-dependent changes in the fauna occur only in the western and northern parts of the region.  相似文献   

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On the Solovetskiye Islands, subtundra forests and forest-tundra crooked forests are considered to be zonal biocenoses, as this region is intersected by the 12°C isotherm for July, which marks the boundary between the northern taiga and forest-tundra zones in northern Europe. The formation of extrazonal tundras on the islands is attributed to the cooling effect of the sea and the prevalence of cold northeasterly winds in the growing period. Herbaceous and herb-bilberry forests similar to their middle-taiga counterparts develop in this region due to a convective heat flow anomaly of high intensity (up to 40–50 W/m2). The phenomenon provides evidence for the existence of an active heat source in the crust under the archipelago. This source is probably a diapir fold involving the upward movement of the mantle.  相似文献   

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长江江苏段鱼类种类组成和优势种研究   总被引:1,自引:0,他引:1  
根据2001~2005年对长江江苏段鱼类的调查与监测,结合鱼类学研究的最新观点,对长江江苏段鱼类历史资料进行整理和归并,结果长江江苏段共记录鱼类161种(19目42科)。本次调查采集到鱼类15目31科108种,其中2个新种,2个省新记录,种类组成以鲤科鱼类为主。根据相对重要性指标(IRI)计算,江苏全江段的优势种分别为鳖hemiculter leucisculus、鲫Carassius auratus auratus (Linnaeus)、鳊Parabramis pekinensis (Basilewsky)、鲤Cyprinus capio Linnaeus、刀鲚Coilia nasusSchlegel、贝氏Hemiculter bleekeriWarpachowsky、似鳊Pseudobrama simony (Bleeker)、香斜棘鱼衔Callionymus olidus Günther、鲢Hypophthalmichthys molitrix (Valenciennes)、草鱼Ctenopharyngodon idellus (Valenciennes);优势种平均体重为0.974~292.431 g。江段鱼类小型化、低龄化仍十分严重。  相似文献   

5.
金沙江干热河谷几种引进树种人工植被的生态学研究   总被引:1,自引:0,他引:1  
采用标准木法和收获法,对金沙江元谋干热河谷几种引进树种的人工植被(即赤桉×新银合欢混交林、赤桉纯林、新银合欢纯林和印楝纯林)各层植被生物量与天然次生植被(坡柳-扭黄茅灌草丛)进行了比较研究,同时对各类植被的物种组成和物种多样性进行了比较分析。结果表明:(1)采用引进树种人工恢复的植被积累了大量生物质,总生物量大小依次为:赤桉×新银合欢混交林(4491 t/hm2)>新银合欢纯林(3991 t/hm2)>赤桉纯林(3857 t/ hm2)>印楝纯林(1306 t/hm2)>天然次生林(935 t/ hm2)。人工恢复植被生物量主要集中在乔木层,天然次生植被生物量主要集中在灌木、草本和凋落物层。(2)人工恢复植被的物种数均少于天然次生植被,而且不同植被的物种数和物种组成也存在差异。(3)各植被的Shannon wiener多样性指数和Margalef丰富度指数均表现为:印楝纯林>坡柳-扭黄茅灌草丛>赤桉纯林>赤桉×新银合欢混交林。在Alatato均匀度指数方面,各人工植被之间的差异不大,但人工植被与天然次生植被之间有显著差异。〖  相似文献   

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外来种入侵对乡土生物多样性的影响机制   总被引:7,自引:1,他引:6  
外来种入侵是全球性变化研究的重要组成部分,已经成为各国生物多样性保 护和管理的核心问题。近年来,大多数人给予了外来种对生态系统的负面作用充分的论述和研究,而忽视了它们的积极效应。如何客观辨证地评价外来种的作用和可能的影响是规避和管理外来种所带来的风险的前提和保障。在综述外来种、乡土种和外来种入侵的基本概念及其危害情况的基础上,系统阐述了外来种侵入和种群扩大对生物多样性所带来的正负两方面的影响。外来种入侵可能的影响途径及其机制主要包括:(1)竞争与排斥;(2)杂交;(3)打断或改变食物链关系;(4)带入病毒等。外来种入侵对乡土物种多样性的影响途径和机制实际上是上述众多因素综合作用的结果。外来种之所以给生态系统和人 类带来危害和损失,根本原因在于人们缺乏外来种入侵的相关知识以及预防手段和意识,更缺乏对外来种的有效管理。规避外来种所带来的风险,最关键是要尽可能地避免人为的、有意的协助外来种的入侵,并在做好各种安全措施后,有计划、有步骤地慎重引入,科学管理,规划发展。目前对外来种入侵的生态学知识还是零碎的、局部的、表象的,深入研究外来种的生物学生态学特性及其入侵的生态学机制是当前最为急迫的工作。建议我国近期加强外来种的本底调查与现状评估、外来种入侵的通道与入侵过程及其影响因素、外来种入侵的生态过程及其效应以及外来种入侵的进化后果等方面的工作。  相似文献   

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Characteristics of the small-mammal populations inhabiting forest biocenoses in the Middle Ural state reserves have been analyzed over in the period from 1987 to 2002. During this period, the habitats of these animals were considerably destabilized due to windfalls and fires. The environmental characteristics of animal microhabitats at different stages of environment destabilization have been described quantitatively. Changes in the long-term cycles of the population dynamics of the dominant forest vole species caused by the destabilizing factors have been found. Redistribution of species dominance with respect to abundance has been demonstrated.  相似文献   

8.
The small-rodent populations of five collective gardens have been studied. The example of one of the populations has been used to monitor the annual cycle of population size. The species composition and animal number depends on the biotope, climatic conditions, and the anthropogenic load. The ratios between species in the gardens and neighboring biotopes differ from each other, with different species being dominant. It is assumed that small mammals use garden plots as refugia.  相似文献   

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The influence of intra- and interspecific competition of common and East European voles on their daily activity was studied in 34-m2 enclosures at the Chernogolovka Experimental Research Station (Moscow Region). Family groups of animals captured in the same biotopes were placed in enclosures and, 25 day later, their daily activity was observed. Thereafter, the animals were pooled and observations were repeated 25 days later. The experiment consisted of three stages. At the first stage, the daily activity, time budget, and social behavior of common voles were studied before and after pooling different family groups; at the second stage, the same was performed with East European voles; and at the third stage, with both species. The species proved to use different strategies for alleviating intraspecific competition: in common voles, this was segregation of ecological niches via desynchronization of daily activity; in East European voles, conversely, aggregation in groups and synchronization of activity. Under experimental cohabitation, the strategy of the common vole, a more aggressive species, was to force out the other species, ecologically similar but less competitive; the strategy of the East European vole was aimed at avoidance via segregation of ecological niches in time.  相似文献   

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定位研究了25a来缙云山银木荷林物种组成及多样性在自然演替过程中的动态变化。结果表明,银木荷林维管植物物种由57种(隶属于24科,46属)减少到38种(隶属于19科,26属)。林下草本和层间植物逐渐消失,胸径大于7.5cm的乔木层树总胸断面积有所减少。尽管群落物种组成以及多样性发生改变,但是银木荷依然是优势树种,处于林冠层,而林冠亚层的白毛新木姜子、四川山矾、长蕊杜鹃逐渐增多,短刺米槠逐渐减少。群落乔木层4个α多样性指数都呈下降趋势,丰富度指数由2.98下降为1.99,Shannon-Wiener指数25a间减小了0.34,Simpson指数和Pielou指数变化都很小;β多样性分析结果显示,银木荷群落的物种差异很大。研究表明,25a间群落物种差异显著。揭示缙云山银木荷林自然演替过程中的物种组成和多样性变化规律,可为缙云山保护区及长江流域中上游亚热带常绿阔叶林的银木荷群落的管理提供一定的参考价值。  相似文献   

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The long-term population dynamics of rodent communities in park forests of Yekaterinburg was studied. The results showed that deep population depressions occurring in natural communities are not characteristic of the urban communities. In the urban environment, the density of rodents is always maintained at a relatively high level due to the appearance of species that are atypical for the natural communities. This fact deserves attention in view of the increasing risk of tick-borne encephalitis (TBE) in the region, as a high rodent abundance may provide for the maintenance of a stable TBE focus in the city.  相似文献   

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The functioning of two foci of helminth diseases caused by trematodes Apophallus muehlingi and Rossicotrema donicum has been studied in the Volga Delta. The origin of these foci is related to the expansion of species ranges of Lithoglyphus snails, intermediate hosts of trematodes. Introduced mammal species, the raccoon dog Nyctereutes procyonoides and American mink Mustela vision, are involved in the circulation of the invasion.  相似文献   

17.
Data collected between 1987 and 2002 have been used to analyze the structure of small mammal communities in parks and public gardens of the city of Moscow. With regard to several ecological parameters, four categories of parks markedly differing in biotopic conditions have been distinguished. The least stable zoocenoses are formed in deteriorating parks. More favorable ecological conditions exist in public gardens and regular parks, where not only synanthropic but also hemisynanthropic rodents can be found. The fauna of small mammals in landscape parks is similar to that in forest cenoses, but this fauna in park forests better complies with the concept of forest community.  相似文献   

18.
Small mammal communities inhabiting natural and anthropogenically transformed areas of the right-bank region of Saratov oblast are fairly similar in species composition. They are represented by wide-spread, common species that, against the background of a low population density of typical steppe species, make a major contribution to the community. The highest ecological tolerance is characteristic of the striped field mouse Apodemus agrarius, which is widespread in the study region and dominates in the majority of natural biotopes and in agrocenoses; the common vole Microtus arvalis is scarce in agrocenoses.  相似文献   

19.
The ecotypic structure of two grayling species in Eurasia is considered. Based on original and published data, the development of ecological forms in water bodies of different kinds is analyzed. Parallelism in the emergence of highly similar forms in different sites of the ranges is demonstrated. Distinctive features of ecotypes and their internal structure are described. The causes and rate of establishment of forms with a short life cycle are discussed.  相似文献   

20.
The results of long-term studies on phytoplankton in the cooling reservoir of the Beloyarsk Nuclear Power Plant (the Middle Urals) are reviewed. Altogether, 199 taxa of the species and subspecies rank have been recorded, including 144 taxa described in this water body for the first time. The algoflora of the reservoir consists mainly of widespread and eurybiontic freshwater species.  相似文献   

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