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1.
Fifteen A. baikalensis populations growing in natural and disturbed habitats in the dark-taiga forest belt of the Western Sayan Mountains have been studied with respect to age composition, numbers, and variation and interrelation of vegetative characters and parameters of productivity. Specific features of the effect of gaps in the tree canopy on the state of A. baikalensis cenopopulations have been revealed.  相似文献   

2.
Gradients of Nei's genetic distances between 15 samples of Pinus sylvestris L. trees were analyzed along three submeridional transects, from Scandinavia to the Mediterranean and Transcaucasia. As a result, distinct chorogenetic differentiation was revealed between the populations of this species growing in climatically specific regions of northern and southern Europe. Considerable Nei's distances (DN = 0.045–0.056) and their gradients, combined with differences in stable phenotypic characters (the composition of monoterpenes and morphological parameters of cones) determined at the Pyrenean and Caucasian mountain borders, suggest that the P. sylvestris species structure includes two South Eurasian subspecies, the Pyrenean P. sylvestris L., ssp. iberica Svoboda and the Transcaucasian P. sylvestris L., ssp. hamata (Stev.) Fomin.  相似文献   

3.
A comparative analysis of spatial population structure in the northern red-backed vole (Clethrionomys rutilus Pall.) and large-toothed red-backed vole (Cl. rufocanus Sund.) has been performed in the middle taiga zone of the Middle Irtysh region (Omsk oblast). Populations of these species are represented by sets of territorial groups whose numbers and spatial distribution change from year to year depending on the ratio of these species in a biotope and their population density. There is no significant interspecific competition between cohabitant Cl. rutilus and Cl. rufocanus. In particular, this follows from the fact that the population density and distribution pattern of one species are independent of those of the other species. It has been found that the size of home ranges in Cl. rutilus inversely depends on its population density, with that in Cl. rufocanus remaining approximately the same at different population densities, and that the structure of the resident part of the population in both species changes during the season, as voles from neighboring habitats or dispersing voles settle in the study area.  相似文献   

4.
Variation and intraspecific differentiation of Oxytropis chankaensis Jurtz. (Fabaceae), a plant endemic to the Russian Far East, have been studied by analyzing a complex of morphological characters. A high level of morphological variation has been revealed, and the most variable populations growing in the Khankaiskii Nature Reserve have been identified. Populations growing in the zone of anthropogenic impact are characterized by low values and reduced variability of test characters. Distinct morphological differentiation of O. chankaensis populations has been observed.  相似文献   

5.
The effect of long-term exposure to natural excretions of the European polecat on the morphological parameters and hormonal status of adult male Campbell hamsters (Phodopus campbelli) and dwarf hamsters (Ph. sungorus) was studied. Exposure to volatile components of natural excreta of a potential predator did not have any significant effect on hamsters. The combined influence of volatile and nonvolatile components of the polecat’s excretions caused physiological stress in Ph. campbelli, while in Ph. sungorus, on the contrary, an increase in thymus weight and the plasma testosterone level was recorded.  相似文献   

6.
The accumulation of fluorine in the trunk wood and branches of Larix gmelinii growing on soils with a naturally increased fluoride content and of L. sibirica growing in a zone affected by atmospheric emissions from an aluminum plant has been studied. Based on results of in vivo and in vitro experiments, it is concluded that larch trees manifest individual differences in their response to fluorine.  相似文献   

7.
Phenotypic diversity in populations of Polyommatus icarus Rott. (Lepidoptera, Lycaenidae) is regarded as a component of the ecocenotic strategy of the species, trends in which may serve as markers characterizing the state of natural populations.  相似文献   

8.
The composition and structure of the Gray mussel (Crenomytilus grayanus) community in Vostok Bay of the Sea of Japan have been studied. A total of 165 species have been identified in the macrobenthos. Its species composition has changed insignificantly since the 1970s. The total biomass of the biocenosis has decreased, and the size-age composition of the C. grayanus population has changed due to poaching. The trophic structure of the community has also changed, with the Shannon indices of species diversity and equitability (E) becoming lower, due to intensive organic pollution of Vostok Bay resulting from increasing recreational activities and sewage discharge.  相似文献   

9.
The formation of the spatial structure of the willow warbler (Phylloscopus trochilus) and little bunting (Emberiza pusilla) populations differing in the degree of site fidelity was studied. The area populated by each species was subdivided according to how regularly its parts had been populated over a 16-year period and how synchronous the population dynamics were. The validity of some hypotheses detailing the population formation was tested by comparing simulated population dynamic curves in segments differing in quality with actual curves.  相似文献   

10.
This paper documents zootherapeutic practices in Northeast Brazil. It is primarily based on field surveys carried out in fishing villages located in the States of Maranhão and Paraíba, where dwellers provided information on snake species used as medicine, body parts used to prepare the remedies, and the illnesses to which the remedies were prescribed. The species used as medicinal drug and their respective families were: Crotalus durissus (rattlesnake), Bothrops leucurus (‘lance head’, a venomous snake), and Lachesis muta (bushmaster) of the family Crotalidae; and Boa constrictor (boa constrictor), Epicrates cenchria (‘salamanta’), and Eunectes murinus (anaconda) of the family (Boidae). These zootherapeutical resources were used for the cure of 14 illnesses. The most commonly cited species were Crotalus durissus (n=26) e Boa constrictor (n=6), Apparently, the medicinal use of snakes does not pose a threat for their population in the studied sites.  相似文献   

11.
Molecular genetic methods (AFLP and ITS1–5.8S–ITS2 rDNA analysis) have been used to study the level and structure of genetic diversity in relict populations of the Ural endemic Gypsophila uralensis Less. in the northeast of European Russia. Intraspecific genetic differentiation is most clearly manifested between G. uralensis Less. subsp. pinegensis (Perf.) Kamelin locally endemic to the north of Europe (Arkhangelsk oblast, locus classicus) the population of G. uralensis Less. subsp. uralensis on limestone outcrops along the Shchugor River, the Subpolar Urals. The cluster of Timan populations (on limestone outcrops along the Svetlaya, Pizhma, and Myla rivers) is autonomous and genetically heterogeneous. Genetic distances between model G. uralensis s.l. populations are correlated with geographic distances. The size and abundance of relict populations show a descending gradient in the forest zone, and parameters of their genetic diversity [1] and unbiased expected heterozygosity have been found to decrease along this gradient.  相似文献   

12.
The structure of genotypic diversity in eight populations of the clonal triploid (2n = 3x = 36) tulip Tulipa riparia inhabiting floodplain communities in the Southern Urals was studied. Analysis of nine polymorphic enzyme systems (ADH, IDH, SkDH, PGI, PGM, FDH, NADHdh, C-EST, GOT) was performed to identify clones. Both monoclonal (D = 0) and polyclonal populations with multiple genotypes from 3 to 12 (D from 0.73 to 0.91) were identified. The polyclonal populations had a high level of heterozygosity. Dispersal of propagules (bulbs) along rivers and even from one bank of a river to the opposite was detected. Some clones disperse along riverbanks to the distance of hundreds meters (up to four kilometres). At the same time, there is an effect of “isolated” or “closed” populations. Almost each sequentially arranged population in one river system have its own set of genotypes. Assessment of the state of the reproductive system components indicates presence of a rare sexual reproduction supporting genetic diversity of T. riparia.  相似文献   

13.
In this study we investigated the size-dependent reproductive pattern of Inula racemosa and I. royleana (Asteraceae) growing at different reaches in the environs of the Kashmir Himalaya. Size effects on reproductive pattern were evaluated by determining the size-dependency of flowering probability and reproductive effort. The results showed that the probability of flowering increased significantly with the size of the plant in all populations, indicating that individuals do not flower until they reach a threshold size and considerable between-site differences were found in the slope and the intercept of the regression between plant size and flower production. In I. racemosa, populations at high altitudes had significantly lower threshold sizes for reproduction and showed sharp increase in flowering probability with plant size, compared to other populations at lower altitudes. However, no pattern in size-dependent flower production was found relative to the altitude in I. royleana, as flower production at some sites, at high altitudes, increased more steeply with plant size than at other sites. For both taxa, reproductive effort decreased allometrically as adults grew, as can be interpreted from the allometric relationship between reproductive and vegetative biomass. Further studies are required to determine whether population differentiation in size-dependent reproductive pattern is maintained by selection.  相似文献   

14.
Specific ecological features of trees (Chosenia arbutifolia and Betula lanata) and shrubs (Pinus pumila and Duschekia fruticosa) at the northern limit of their distribution are compared. New biomorphological adaptations of these species under extreme conditions are described.  相似文献   

15.
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   

16.
A comparative analysis of field observations and experiments on the distance and rate of dispersal of self-sown Scotch pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) progeny has shown that the rate of their hydrochorous dissemination downstream is an order of magnitude higher than the rate of dispersal in upland areas. A hypothesis assigning priority to the role of hydrochory in the expansion of conifer populations to the tundra (periglacial) zone along with climate warming has been formulated and substantiated by comparative isozyme analysis of populations in transects lying along and across rivers.  相似文献   

17.
The isotope ratios δ13C and δ15N and the contents of nitrogen, carbon, and mineral substances have been studied in the leaves of Ephedra sinica, Allium polyrhizum, and Stipa glareosa plants growing separately or together under arid conditions of the Gobi (Mongolia). The contents of nitrogen, mineral substances, and δ15N have proved to decrease when these species grow together, providing evidence that they compete for environmental resources. The nitrogen content decreases to the greatest extent in E. sinica due to the low competitiveness of this species. The direction of change in δ13C in E. sinica is opposite to that in A. polyrhizum and S. glareosa. Differences in physiological mechanisms of adaptation to stress between these species provides a basis for attributing them to different functional groups and for predicting the result of their competition upon changes in climatic conditions.  相似文献   

18.
Methods of geometric morphometrics and population phenogenetics have been used to evaluate morphogenetic rearrangements in two sympatric species of Myodes voles (M. glareolus Schreb. 1780 and M. rutilus Pall. 1779) from syntopic populations recovering after exposure to local “ecological vacuum” created as a result of rodent extermination in a natural focus of hemorrhagic fever in the southern taiga subzone of the Udmurt Republic. The model used in the study simulates the situation that arises upon nonselective elimination of rodent populations and communities in spring and their subsequent recovery. Analysis of variation in the size and shape of the mandible and in a complex of 30 nonmetric cranial characters has revealed similar (parallel) and species-specific morphogenetic and epigenetic changes occurring during the recovery of local rodent community. Species-specific differences in the pattern of change in the parameter characterizing within-group morphological disparity in the mandible shape (MNND) have been revealed between the dominant species (M. glareolus) and the subdominant species competing with it for territory (M. rutilus). Different reactions of close Myodes species in the course of filling the ecological vacuum are considered as a result of reduction in the level of competition for the subdominant species and a compensatory increase of morphological disparity in the dominant species under conditions of low density and incomplete composition of the community, in accordance with Chernov’s (2005) ecological compensation principle.  相似文献   

19.
Parameters of reproduction of the Siberian stone pine (Pinus sibirica), including radial and apical tree increments, the age structure of stands, the amount of young growth, and its distribution along an altitudinal gradient, have been studied in the forest-tundra ecotone of the Western Sayan. The results show that, over the past 30 years, P. sibirica undergrowth has expanded to the mountain tundra belt, the apical and radial tree increments and stand density have increased, and the life form of many P. sibirica plants has changed from prostrate to erect (single-or multistemmed). These changes correlate with the dynamics of summer temperatures and monthly (in May and June) and annual precipitation. The rise of summer temperatures by 1°C promotes the expansion of P. sibirica undergrowth for approximately 150 m up the altitudinal gradient.  相似文献   

20.
The dependence of the annual increment of vegetative organs on air temperature and humidity and the amount of precipitation per phenophase, as well as the period of their growth in Scots pine, were studied in the forest-steppe zone of Cisbaikalia. The multiple effect of variation in environmental conditions on the annual increment of organs increased when precipitation in September of the previous year was taken into account. These factors proved to have a stronger effect on variation in the annual increment of needles (R 2 = 0.59, p = 0.00005) than that in the annual ring width (R 2 = 0.38, p = 0.0002).  相似文献   

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