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1.
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   

2.
Basic climatic parameters (annual average air temperature and annual amount of precipitation) over 12–25 years have been analyzed with regard to their values corresponding to different levels of abundance in three species of forest voles: Clethrionomys glareolus (in 11 areas of the species range), Cl. rutilus, and Cl. rufocanus (in three areas each). The results show that the abundance of all these species correlates significantly with fluctuations of annual average temperature, with the correlation being negative in Cl. glareolus and Cl. rufocanus but positive in Cl. rutilus. In addition, the abundance of Cl. rufocanus shows a significant correlation with annual precipitation. Voles inhabiting different geographic regions may reach high abundance under different conditions. As for the species range as a whole, however, Cl. glareolus is more ecologically flexible than the other two voles. This species is also more warmth- and moisture-loving, while Cl. rufocanus is more cold-loving and xerophilous, with Cl. rutilus occupying an intermediate position between them. Clethrionomys rutilus is most temperature-dependent and stenothermic among them, whereas Cl. glareolus is indifferent to the factors studied.  相似文献   

3.
Functional-ontogenetic determination of age-dependent dental changes (ADCs) in voles has been demonstrated. The relationship between ADCs and the functional state of animals has been analyzed. A scheme and a table for determining individual chronological and biological ages in the bank vole (Clethrionomys glareolus Sch.) are proposed, which markedly improve the accuracy of results. Cases of rodent maturation and breeding in winter are considered.  相似文献   

4.
Using methods of geometric morphometrics, significant differences have been revealed in manifestations of variability and morphological disparity in allochronous samples from the population of model species, the bank vole (Clethrionomys glareolus Schreb. 1780), in the Middle Urals at different levels of rodent community (taxocene) completeness in different years. Two states of the taxocene—oligospecific (two species) and polyspecific (five species)—and the level of relative abundance of bank voles (high or low) have been taken into account. Comparative analysis of variation in the size and shape of the mandible in same-aged (late-summer) young of the year has shown that significant morphogenetic differences exist between the animals sampled from the rodent taxocene at its different states (oligospecific and polyspecific) and, to a lesser extent, at high and low levels of abundance. The level of variation and the parameter of intragroup morphological disparity (MNND) in the mandible shape reach a maximum when the community has a reduced composition and decrease to a minimum when its composition is complete (i.e., in the oligo- and polyspecific taxocene). A parallelism is observed in the manifestation of morphofunctional changes of the mandible in male and female voles under conditions when the taxocene has high abundance and oligospecific composition or low abundance but polyspecific composition. Different morphogenetic responses of the population to oligo- and polyspecific composition of the community are considered as a compensatory increase of morphological disparity in the dominant species (the bank vole) under conditions of incomplete composition of the taxocene and low population density, in accordance with Chernov’s ecological compensation principle.  相似文献   

5.
Study results on the condition of endogenous ethanol—acetaldehyde system in northern red-backed vole (Myodes (=Clethrionomys) rutilus Pallas, 1779), common species of northern latitudes, are presented. Concentrations of endogenous ethanol (EE) and acetaldehyde (EA) in blood, activities of alcohol dehydrogenase in ethanol oxidation reactions (ADHI) and liver acetaldehyde (ADHII) and aldehyde dehydrogenase (ALDH) reduction, and catalytic parameters of these enzymes are determined for winter and summer periods. Changes in ethanol—metabolizing dehydrogenase enzyme system in northern red-backed vole leading to statistically significant (p < 0.01) increase in blood EE and EA concentrations compared to white nonpedigreed laboratory rats without adaptations to cold (especially in winter period) are determined to serve ecoadaptive, antistress functions, comprising one of the systems for regulation of metabolism intensity in small mammals inhabiting extreme northern conditions. Ecological—physiological functions of EE and EA system are increasing the organism’s resistance to the influence of cold temperatures and maintaining thermoregulation even under rapid, considerable environmental temperature drops.  相似文献   

6.
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   

7.
Determined the contribution of root derived CO2 efflux to total CO2 efflux (including root and non-root derived CO2 efflux) is import to grope the mechanism of CO2 efflux, however, becaused of ‘rhizoshere priming effect’ (RPE), it is difficult to achieve in practice. In this study, we attempted to estimate the RPE via comparing basal soil respiration (Rb) achieved by two different methods namely, y-intercept regression and direct bare plot approach in an arid cotton field, central Asia. On the basis of the y-intercept of linear regressions between below-ground respiration (BGR) and root biomass, Rb was indirectly calculated. Comparing with the first approach, the second approach involved direct measurements of soil respiration from bare plots. Rb estimated by y-intercept method contained the component of RPE whereas direct bare plot did not. We found that RPE showed a phenological trend with highest value in flowering stage at 0.145 g CO2 m–2 h–1 and lowest at budding stage (0.007 g CO2 m–2 s–1), even after the data had been corrected for the influence of soil temperature. We concluded that RPE needed to be considered when Rb was estimated by y-intercept approach.  相似文献   

8.
Experimental studies of interactions between two amphipod species (Gmelinoides fasciatus and Gammarus lacustris) showed that predation is the basic mechanism accounting for their mutual exclusion in nature. Mortality from predation among similar-sized specimens of both species at an equal abundance ratio was similar (24–25% in G. lacustris and 27–30% in G. fasciatus). The displacement of G. lacustris by G. fasciatus was observed when the latter was dominant. Adult G. fasciatus and G. lacustris successfully preyed on juveniles of their competitors and did not differ significantly in daily food consumption as a percentage of body weight: 6–24% at a fresh body weight of 18–24 mg in both species. The potential for rapid population growth under new conditions contributed to the success of the invasive Baikal species G. fasciatus in displacing G. lacustris from many water bodies of Russia.  相似文献   

9.
Eomecon chionantha Hance, the only species in the genus Eomecon, is an angiosperm species endemic to China. Here we investigated the pollination syndrome, pollinator generalization of E. chionantha. Our results showed that the individual flower longevity of E. chionantha was 3–5 days. The flowering phenology of E. chionantha can be divided into five phases. We found significant differences in the pollination efficiency of the different insects visiting E. chionantha with bees and flies being the most efficient pollinators. This, in addition to floral morphology and phenology, suggests that E. chionantha is generalized on bees and flies and possesses an outcrossing, partially self-compatible and pollinator-dependent breeding system.  相似文献   

10.
Present study was carried out to determine pollinators’ diversity and their efficiency with modular approach; foraging behaviour, number of loose pollen adhered on their body and number of pollen deposited on the stigma. The observations explicitly indicate that Megachile spp., Xylocopa tenuiscopa, Amegilla zonata and Nomia sp. were true pollinators and out of these, Megachile spp. were key pollinators of pigeonpea. Among megachilids, Megachile lanata was the most efficient pollinator. Sufficient pollination meticulously accomplished in pigeonpea by true pollinators under this agro-ecological region.  相似文献   

11.
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   

12.
The composition and contents of secondary metabolites in Flavocetraria lichens from Eastern Siberia were analyzed using herbarium specimens. Based on the composition of identified metabolites, three F. cucullata chemotypes and two F. nivalis chemotypes were distinguished. Distinct geographic differentiation between the F. cucullata chemotypes was revealed, probably reflecting their adaptation to environmental conditions. The content of usnic acid in F. cucullata thalli was found to correlate with the latitude of growing region. This may be regarded as evidence for a protective role of this metabolite in lichens growing at high latitudes and exposed to excess solar irradiation during the polar day.  相似文献   

13.
A study has been performed on the ecological, morphological, and genetic diversity of burbot (sample size n = 204 and n = 134, respectively) from eight localities of the Ob–Irtysh and Taz river basins, Western Siberia. Fish differentiation in body size and weight depending on the dominant type of migration behavior, foraging conditions, and physiographic features of habitats has been revealed. A high genetic diversity (854-bp mtDNA control region) and a low level of between-sample differentiation is evidence for high intergroup gene flow.  相似文献   

14.
The linear increment of Sphagnum fuscum and S. magellanicum in ombrotrophic mires of Western Siberia has been measured during two years over a transect about 2500 km long extending from forest–steppe to forest–tundra. Along the latitudinal gradient, the increment of both species has proved to be correlated with annual average air temperature and, in S. magellanicum, also with annual precipitation. The determinants of their growth differ between the southern, central, and northern parts of the study region. At the regional level, the annual and summer precipitation plays a more important role than the average air temperature. The increment of S. fuscum in the southern part is positively correlated with the amount of precipitation and negatively correlated with summer temperature, whereas the situation in the central part is inverse. In S. magellanicum, the linear increment is directly dependent on the annual average temperature and annual and summer precipitation in the south and on the annual and summer precipitation in the north of Western Siberia. The dynamics of linear growth of both species in bog pine forests during the growing season are similar: its rate is the highest in June, when the linear increment of S. fuscum and S. magellanicum amounts to 60 and 85% of the annual total, respectively.  相似文献   

15.
Despite there being considerable research and knowledge surrounding the risks of climate change on agricultural productivity, fewer studies have examined risks from a whole-of-chain perspective (i.e. from producer to consumer) and the perceptions of consumers about the climate adaptation strategies of food businesses. This paper presents the findings of a survey of 1532 Australian consumers and how they might respond to a food company’s climate adaptation strategy. Three respondent archetypes, ‘Eco-warriors’ (n = 557), ‘Undecideds’ (n = 600) and ‘Abdicators’ (n = 375), were identified based on their perceptions of risks associated with climate change and their attitudes towards climate adaptation. Further analysis was carried out to understand how each group of respondents would respond to adaptation strategies employed by food companies. Based on the findings of this study, two main challenges are presented for food value chains: (1) translating consumer needs and preferences to niche opportunities arising from adaptation and (2) understanding how best to communicate adaptation benefits based on varying attitudes and information needs. By addressing these challenges, synergies between adaptation goals and competitive strategies in food value chains may be achieved.  相似文献   

16.
Magnitudes of land cover changes nowadays can be assessed properly, but their driving forces are subject to many discussions. Next to the accepted role of human influence, the impact of natural climate variability is often neglected. In this paper, the impact of rainfall variability on land cover changes (LCC) is investigated for the western escarpment of the Raya Graben along the northern Ethiopian Rift Valley. First, LCC between 2000 and 2014 were analysed at specific time steps using Landsat imagery. Based on the obtained LCC maps, the link was set with rainfall variability, obtained by means of the satellite-derived rainfall estimates (RFEs) from NOAA-CPC. After a correction by the incorporation of local meteorological station data, these estimates prove to be good estimators for the actual amount of precipitation (ρ RFE1.0 = 0.85, p = 0.00, n = 126; ρ RFE2.0 = 0.76, p = 0.00, n = 934). By performing several linear regression analyses, a significant positive relationship between the precipitation parameter DIFF 5Y (i.e. the at-RFE pixel scale difference in five-year average annual precipitation for the two periods preceding the land cover maps) and the changes in the woody vegetation cover was found (standardised regression coefficient β = 0.23, p = 0.02, n = 108). Despite the dominance of direct human impact, further greening of the study area can be expected for the future concomitantly to a wetter climate, if all other factors remain constant.  相似文献   

17.
The migrations of murine rodents and their capacity for overcoming various obstacles in urbanized environments have been analyzed. Animals marked with tetracycline were captured at different distances from the marking plot. The maximum distance of movement along a straight line was 2030 m for the pygmy wood mouse (Sylvaemus uralensis Pall.) and 430 m for the bank vole (Clethrionomys glareolus Schr.). It was revealed that the pygmy wood mouse can successfully cross various types of landscape discontinuities which can act as movement barriers.  相似文献   

18.
In the Gurbantunggut Desert of Northwestern China, we surveyed the population structure and regeneration characteristics of six Haloxylon ammodendron plantations based on chronosequencing. The results showed that the age class of an individual H. ammodendron plant from youngest to oldest showed growth potential under the present environment. The optimal termination stage of H. ammodendron occurred at 20 years of age, which was accompanied by a regeneration phase at 17 years. The H. ammodendron plantations started to regenerate after 7 years. The maximal height and basal stem diameter of a grade III seedling reached 1.2 m and 1.9 cm in a 17-year-old plantation. In a 33-year-old plantation, the transformation rate of the seedling from grade I to grade III increased up to 92.3%. Although the seedling bank was plentiful in the plantations, the replenishment of the canopy was not continuous and timely. Therefore, measures to further the stability and sustainability of H. ammodendron plantation were necessary.  相似文献   

19.
In 2010, the global burden of foodborne diseases was 33 million Disability-adjusted life years, and 40 % of this burden was for children under 5 years old (Havelaar et al. 2015). Our study site was informal public markets within Mzuzu, Malawi, visited between September and December 2015, during the dry season. From these markets, fresh vegetables, leafy greens (n = 85), tomato (n = 85), and green pepper (n = 35) were analyzed for Escherichia coli. The prevalence of E. coli was highest on leafy greens; it was found in 74 (87 %) of the 85 samples. The prevalence of E. coli in green peppers was found in 2 (6 %) of the 35 samples. The prevalence of E. coli was lowest on tomatoes; it was found in only 1 (1 %) of the 85 samples. The lack of adequate water and sanitation infrastructure in market areas may be contributing to the bacteriological contamination of fresh produce. Providing venders with free access to market area toilets containing hand-washing facilities with soap and wash water with a chlorine solution may reduce bacterial contamination of fresh produce. Universal and sustainable access to water and sanitation services must include informal public market areas to reduce diarrheal diseases transmitted through food within Sub-Saharan Africa countries.  相似文献   

20.
Specific structural features of absorbing roots have been studied in Acer negundo (an invasive species in the southern Cisural region), compared to native Acer platanoides and A. tataricum. A comparative analysis of the diameter of fine roots, stele and bark volumes, and the frequencies of roots with retained primary bark, root hairs, arbuscular mycorrhiza, and dark septate endophytes has been performed in the invasive and native species from four habitats (by two habitats in the forest–steppe and steppe zones). The roots of A. negundo have been additionally studied in trees from two monospecific stands. It has been found that the structure of fine roots significantly differs between the invasive and native species: the roots of A. negundo are larger, with relatively poorly developed root hairs and low occurrence of dark septate endophytes. In monospecific stands, the frequency of mycorrhiza in A. negundo roots is very low, with arbuscules and dark septate endophytes being totally absent. It is concluded that specific structural features of the belowground absorbing apparatus in A. negundo are accounted for mainly by traits autonomously formed in a plant, rather than by characteristics of symbiotic relationships, and that they are not consistent with the assumption that the invasive species can utilize soil resources more effectively or more rapidly than taxonomically close native species.  相似文献   

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