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1.
The results of field studies at the Krasnosamarskii Station of Samara State University (the Samara River valley, the subzone of herb–sheep's fescue–feather grass steppes on ordinary chernozem) have shown that the age structure, ecological density, age index, and regeneration capacity of green strawberry cenopopulations depend on the trophic level and moisture content of soil and on the shading and mulching action of litter.  相似文献   

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For the first time, zooplankton and environmental factors have been studied in winter in the deep stratified lakes Siverskoe, Borodaevskoe, and Vydogoshch. The zooplankton consists of 18–22 species of rotifers, copepods, and cladocerans, including 15–18 specifically winter, cryophilic and eurythermic forms. The populations of zooplankters reproduce actively: males and egg-bearing females (in copepods), females with embryos and eggs in brood pouches (in cladocerans), and females with attached eggs (in rotifers) are present. In lakes Siverskoe and Borodaevskoe (depth 20–24 m), where oxygen deficiency is observed only in the bottom water layer, the zooplankton populates the greater part of the water column and forms a large aggregation in the oxycline and near the bottom. The abundance of bacteria in these zones is high (up to 4–6 × 106 cells/ml). In Lake Vydogoshch (depth 16 m), oxygen deficiency extends to the middle layers, and all zooplankton is distributed above the oxycline. The biomass of winter zooplankton in Lake Siverskoe in 1983 averaged 1.26 g/m3, with a maximum of 4 g/m3; in 1993, 1.4 and 8.04 g/m2; the respective values in Lake Borodaevskoe were 0.98 and 3.1 in 1983 and 0.14 and 1.6 in 1993; in Lake Vydogoshch, 0.15 and 0.24 in 1983 and 1.25 g/m3 in 1993. The development of winter zooplankton is limited by the size of the zone of oxygen deficiency and depends on the amount of food (bacterioplankton). The distribution of zooplankton in the water column and its biomass in individual layers is determined by the rate of methane formation and oxidation.__________Translated from Ekologiya, No. 3, 2005, pp. 201–214.Original Russian Text Copyright © 2005 by Rivier.  相似文献   

4.
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   

5.
The results of the study have shown that the stocks of 90Sr and 137Cs in the frontal part of the EURT are 6700–15000 and 200–400 kBq/m2, respectively. The coefficients of their accumulation in different herbaceous plant species in this impact zone are lower than in other areas. The accumulative capability of plants has probably decreased in the course of selection as an adaptation to the effect of radiation. The viability and growth parameters of Plantago major L. seeds from the EURT zone are similar to those of seeds from the background sample. Cenopopulations chronically exposed to radiation are characterized by a higher mutation rate in the progeny and an unstable response to additional acute irradiation in most characters studied. A high level of inbreeding is observed in all P. major cenopopulations of plantain. The cenopopulation of the impact zone is characterized by a lower variation of allozyme loci, which may be a result of stringent selection for individuals better adapted to the complex of conditions existing in its habitat.  相似文献   

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The placement of 1918 redwing nests has been analyzed, including 214 nests of 90 marked females (2–8 known nests per female). A high level of intraspecific and individual variation in utilization of different types of nest supports is described. It is shown that redwings choose nest sites without regard to previous experience (either positive or negative) or to the placement of their parent nest. Under conditions of the northern taiga, such behavior provides for significant reduction of chick mortality by the end of the season. This is con- firmed by comparison with the song thrush (T. philomelos), which nests mainly on spruce trees.  相似文献   

8.
Two populations of creeping thistle (Cirsium arvense) growing in a field uncultivated for many years and on the sloping bank of an artificial pond were studied with respect to the demographic and chemical composition. The results showed that the contents of some elements in plants depend on specific features of the soil and plant population parameters (abundance, biomass, and ontogenetic composition). Some indices of the content of mineral substances in the population and soil proved to be difficult to interpret unambiguously.  相似文献   

9.
In recent years, the frequent occurrences of marine oil spills have already become one of the major reasons threatening the marine ecological safety of China. In the event of oil spill, other than taking the necessary emergent measures aiming specifically at the damage to the marine ecology and environment, using legal means to assure that the damage liabilities are borne by the responsible persons to protect the national interests are also very necessary. This paper advances five recommendations regarding the development of a system for ecological legal compensations from the standpoint of the current status of legislation and execution of the laws on compensation of oil spill polluting marine ecosystem. These five recommendations include: determination of the status of juristic action in marine ecological and environmental compensations in accordance with the laws, determination of plaintiff of marine ecological and environmental compensations in accordance with the laws, determination of the four basic principles in the legal actions of marine ecological and environmental compensations in accordance with the laws, determination of assessment technical standard of marine ecological and environmental damages in accordance with the laws, and determination of the scope of marine ecological and environmental compensations in accordance with the laws.  相似文献   

10.
In Belarussian Polesye, characteristics of reproduction, population dynamics, and factors responsible for a decrease in the abundance of the pond turtle were studied. The main factors limiting pond turtle reproduction in Polesye include the focal distribution of its populations and limited areas of reproductive biotopes. The pond-turtle popuation itself is characterized by a high potential for reproductive growth; in the current situation, the population growth is mainly limited by a high pressure of oophagous predators and anthropogenic destruction of reproductive sites.  相似文献   

11.
The formation of the species composition and specific functional, physiological, and phenotypic features of populations in technogenic and urbanized areas was studied by analyzing murine rodents, amphibians, and soil invertebrates. It is shown that, against the background of decreasing total abundance and biomass of animals, their formerly continuous ranges become mosaic, with the locally increasing animal density and heterogeneity and specific population dynamics. Species diversity decreases; however, species alien to the natural ecosystems of the given territory appear. Changes in the strategies of reproduction and food resource use were revealed in the species communities of small mammals and amphibians.  相似文献   

12.
The flora of liverworts has been studied in the vicinity of the Bil’chenok glacier (the Ushkovskii volcano, Kamchatka), which is in a zone of volcanic ash fallout. Specific complexes of liverworts growing on young moraine and ash deposits have been identified. These complexes are dominated by thallose marchantioid species. Under the effect of periodic ash fallout (in the absence of glacial activity), communities are formed that contain increased proportions of xerophytes and species preferring sites with a disturbed ground vegetation cover.  相似文献   

13.
The physiological method for estimating production based on the relationship between growth and energy metabolism has been used for calculating model growth curves for the amphipod Monoporeia affinis and comparing them with the results of field studies. Calculations demonstrated that the physiological growth curves fit the results of field observations best under certain conditions which have zoological sense: the growth curve should reflect the actual maximum body size of an animal in the given population, the duration of the life cycle, and the time required for reaching the reproductive size.  相似文献   

14.
The data on the ecology of bilberry and cowberry in the West Siberian Plain, Kuznetsk Ala Tau, and highland Altai are presented. Ecological ranges of these plants and amplitudes of their tolerance for some environmental factors are described.  相似文献   

15.
The life form of G. conopsea (short-lived perennial with annual vegetative renewal) makes it possible to combine the long-term, complete ontogeny and polycarpy of the genet with the short life span and monocarpy of individual daughter ramets. Annual changes in the structural organization of daughter individuals allow the plants to adapt to changing environmental conditions and retain the territory they have occupied. Organismal mechanisms providing for the sustainable development of G. conopsea plants in marginal populations are considered in the context of the concept of multivariant plant ontogeny.  相似文献   

16.
Russian Journal of Ecology - Twenty cenopopulations of Rhododendron dauricum and Rh. ledebourii, two closely related and morphologically hardly distinguishable species, have been studied with...  相似文献   

17.
Data on the abundance and occurrence of 64 odonate species in the Southern Urals are considered. A comparative analysis of the odonate fauna in the early 20th century, in the 1960s and 1970s, and in the early 21st century is performed. On this basis, it is concluded that its structure has been markedly changing with time, with the magnitude of these changes being comparable to that of regional faunistic differences. The causes of these changes are discussed. The apparent enrichment of the odonate fauna is attributed primarily to the appearance of new anthropogenic habitats.  相似文献   

18.
In Yakutia, the brown bear inhabits the forest and forest-tundra zones. Compared to bears from other regions of Russia, Yakutian bears have slightly smaller body and skull sizes and are mainly herbivorous, with their wood spectrum being relatively narrow. Their fecundity averages 1.68 cubs per parous female. The bears make their dens at a depth reaching 2.5–3 m. The denning period begins early and is 195–210 days long. An electroencephalographic analysis of the effect of a 1–10 kDa peptide fraction from the bear brain on Wistar rats has shown that wintering bears are in the state of sleep, or “superficial hibernation.”  相似文献   

19.
The mitotic activity and sizes of corneal epithelial cells in postmetamorphic Rana arvaliswere studied in the populations exposed to different degrees of anthropogenic impact in the city of Yekaterinburg. The studies were conducted at the initial stages of frogs' terrestrial life in three consecutive years. Mitotic activity exhibited a slight positive correlation with the liver index, which indirectly reflects the general metabolic rate in young frogs. The combined estimation of proliferative activity, epithelial cell size, and relative liver weight had the highest information value. There was a relationship between the mitotic index and liver index in young frogs from habitats with the highest level of anthropogenic transformation. This indicates that morphogenesis is well-balanced and is likely to decrease the probability of morphological abnormalities in frogs developing in the unstable environment. This physiological property allows the populations to exist and reproduce in urbanized areas.  相似文献   

20.
It is known that pseudoviviparous plant taxa are most numerous in the Arctic and high mountain regions, where they sometimes account for a noticeable part of the local flora and play an important phytocenotic role. The complex of pseudoviviparous taxa is an interesting model for investigating the processes of hybridogenic speciation, as various mechanisms stabilizing the hybrid genetic systems proved to be effective in them. In particular, this concerns vast and taxonomically complex groups such as the genera Deschampsia, Festuca, and Poa.In this paper, published data on the taxonomy, chromosome numbers, and distribution of pseudoviviparous grasses in the Arctic regions and subarctic mountain systems are reviewed.  相似文献   

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