首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
Analysis of variation in morphological characters of Potanin Altai osman, Oreoleuciscus potanini, from two freshwater and one brackish water lakes of Western Mongolia has shown that specimens of different ecological forms—herbivorous and piscivorous—form two integral and, at the level under consideration, internally indivisible units in the system of phenetic diversity of the species O. potanini.  相似文献   

2.
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   

3.
The amino acid spectrum of blood plasma in three bat species (Myotis dasycneme, Pipistrellus nathusii, Vespertilio murinus) inhabiting the Urals has been studied for the first time. The bats were trapped in the zone of their high abundance in Chelyabinsk oblast (2013–2014). Free amino acids were determined by liquid ion exchange chromatography (a total of 384 determinations). It has been shown that the plasma amino acid spectrum consists of 22 amino acids in subadult bats of all three species, but there are species-specific differences in their concentrations. The total amino-acid pool concentration in migratory P. nathusii and V. murinus exceeds that in resident M. dasycneme by factors of 2.9 and 1.8, respectively. Migratory species are characterized by a high concentration of plasma arginine: it is six times higher in V. murinus than in M. dasycneme, and in P. nathusii arginine accounts for 25.4% of the amino acid pool. The group of glucogenic amino acids is prevalent in the blood plasma of migratory species (75% in V. murinus and 79% in P. nathusii), while in M. dasycneme the total proportion of lysine, glycine, and glutamic acid is 2.3 times lower than in P. nathusii and 1.7 lower than in V. murinus (p < 0.05). These results provide evidence for significant differences in the contents of free blood plasma amino acids between migratory and resident bat species.  相似文献   

4.
The taxonomic diversity of the Hirudinea fauna and its dependence on the ecological conditions in the Bukhtarma Reservoir (Eastern Kazakhstan) have been studied. The morphological analysis has shown that these leeches belong to two orders and three families: Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and Arhynchobdellida (family Erpobdellidae). On the whole, eight leech species from five genera (Alboglossiphonia, Helobdella, Theromyzon, Piscicola, and Erpobdella) have been identified. Among them, there are three glossiphoniid species (A. heteroclite, H. stagnalis, and T. tessulatum), two species of piscicolids (Piscicola geometra and Piscicola sp.), and three species of predatory leeches (E. octoculata, E. vilnensis, and Erpobdella sp.). Possible effects of hydrochemical parameters of the aquatic environment on the species diversity have been analyzed. Correlation has been revealed between the abundance of species and the physical and chemical characteristics of the environment.  相似文献   

5.
Geometric morphometrics has been used to reveal coupled geographic variation in the mandible shape in two sympatric rodent species, the pygmy wood mouse (Sylvaemus uralensis Pall.) and bank vole (Myodes glareolus Pall.), in the Southern Urals. It has been shown that syntopic samples synchronously collected from the local communities of these species usually display similar, parallel, and unidirectional morphological changes as demonstrated by comparison of species pairs from different localities. The degree of concordance in geographic variation of the species makes it possible to estimate their coevolutionary potential within local communities: the wider the range of ecological conditions under which parallel variation of sympatric species is observed, the higher is their coevolutionary potential.  相似文献   

6.
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   

7.
The results of long-term observations (1983–2013) on the dates of arrival of migratory birds to the Ilmen State Reserve are presented. Based on their analysis, it is conclude that (1) there is no significant positive trend of spring temperatures in the territory of the reserve, and (2) an earlier arrival of the majority of bird species is not observed, unlike in Europe. The arrival has shifted to earlier dates in the Common Chaffinch (Fringilla coelebs), White Wagtail (Motacilla alba), and Black Kite (Milvus migrans). On the other hand, the arrival of the Tree Pipit (Anthus trivialis) is observed later than usual. Multiple regression analysis has shown that the arrival dates of most species that nest in the reserve are determined by the temperature regime of spring months in their nesting area.  相似文献   

8.
Methods of geometric morphometrics have been used to estimate the influence ratio of nonselective elimination and drought factors on variation in the shape and size of the mandible in the population of bank vole (Clethrionomys glareolus Schreb.) in the southern taiga subzone. Nonselective elimination of rodent populations for medical and sanitary purposes was carried out in a felling site located in a focus of hemorrhagic fever, in the spring of a climatically normal year and of a dry year. The summer samples of mature young of the year from control bank vole colonies and impact colonies (i.e., recovered after deratization) in adjacent years have been compared. The results show that drought, nonselective elimination, and the interaction of these factors have significant effects on the size and shape of the mandible. Changes in its shape under drought conditions are largely due to allometry. Morphogenetic effects of nonselective elimination are highly repeatable between climatically different years. A significantly higher level of within-group morphological disparity (MNND) of the undisturbed control cenopopulation in a dry year has been revealed, which indirectly indicates a stronger destabilization of morphogenesis upon exposure to the autecological factor. Every ecological factor contributes to the development of specific configurations of the mandible; i.e., it induces certain changes in morphogenesis in response to aut- and synecological effects and their combination.  相似文献   

9.
The seasonal variation of forewing size and shape was analyzed in adults of different seasonal generations of two polyvoltine species of whites: Pieris rapae and P. napi (Lepidoptera: Pieridae). Particular morphological features of the forewing are characteristic of each seasonal generation of adults independently of their sex and species. Adults of the spring generations have the smallest wings, elongate and pointed. Adults of the summer generation have the largest, broad and rounded wings over the entire summer season. Adults of the autumn generation have wings similar in shape and size to those of the summer generation, but somewhat smaller and more elongate. Differences between seasonal generations in forewing shape are linked to differences between adults of each generation in adaptation to dispersal.  相似文献   

10.
The results of regression and correlation analyses of long-term data (1971–2005) on the dates of arrival of 16 bird species to the Il’men State Nature Reserve (the Southern Urals) show that they have not changed in most of these birds, unlike in many countries of Europe and North America. This is explained primarily by the absence of any significant trends in the dynamics of spring air temperatures in the study region. Only the herring gull Larus argentatus and the lapwing Vanellus vanellus have shown a significant tendency to arrive earlier, while the garganey Anas querquedula has shown a tendency to arrive on later dates in the past two decades. Nevertheless, interannual fluctuations in the dates of arrival are well manifested in both early arriving species wintering in Europe and late-arriving species wintering in Africa. These fluctuations largely depend on temperature conditions in spring. As a rule, almost all species studied—from waterbirds to passerines—appear in the Il’men Reserve earlier in years with early and warm springs than in cold years. Hence, spring weather is the key factor determining the dates of arrival of migratory birds to the study region.  相似文献   

11.
Based on analysis of the frequencies of nonmetric cranial characters, the ratio of interpopulation and interspecific differences has been studied in populations of two genetically identified cryptic species of wood mice, A. uralensis and A. ponticus, living under different ecological conditions in the Northern Caucasus. Hybridization between these species has not been reported previously, but interspecific phenetic distances indicate that differences between them do not exceed the level characteristic of subspecies, with morphological differentiation between A. uralensis populations of the Central and Western Caucasus being weakly expressed. It is hypothesized that the low level of intra- and interspecific differences is explained by the sympatric and symbiotopic origin of both species in the Western Caucasus. This may account for the retention of their similarity in ecological requirements for the environment and, consequently, only slight morphological disparity in similar biotopes.  相似文献   

12.
An analysis of correlations between metric leaf characters and climatic parameters of habitats in the Siberian alder (Alnus hirsuta) has shown that phenotypic variation in this species depends on the gradient of climatic factors and that the morphological structure of the species is largely determined by variation in climatic conditions within the species range.  相似文献   

13.
Six fish species were collected: summer trout (Salmo alar), rock fish (Roccus lineatus), pink snapper (Lutianus ava), croaker (Stellifer lancelatus), sheepshead (Diplodus holbrooki) and spanish mackeral (Scomberomorus maculatus). Seven trace elements were determined by flame atomic absorption spectrophotometry. The results indicate that the trace elements iron, copper, zinc, mercury, chromium, and nickel show higher levels in the livers than in the flesh of all the six fish species. Surprisingly, magnesium concentration levels were consistently higher in flesh than in the livers of all six fish species.  相似文献   

14.
We examined the long-term effects of a single application of potassium (K) fertilizer (100 kg K ha−1) in 1992 on 137Cs uptake in a forest ecosystem in central Sweden. 137Cs activity concentrations were determined in three low-growing perennial shrubs, heather (Calluna vulgaris), lingonberry (Vaccinium vitis-idaea) and bilberry (Vaccinium myrtillus), and in four wild fungal species (Cortinarius semisanguineus, Lactarius rufus, Rozites caperata and Suillus variegatus). Uptake of 137Cs by plants and fungi growing on K-fertilized plots 17 years after application of the K fertilizer was significantly lower than in corresponding species growing in a non-fertilized control area. The 137Cs activity concentration was 21-58% lower in fungal sporocarps and 40-61% lower in plants in the K-fertilized area compared with the control. Over the study period, this decrease in 137Cs activity concentration was more consistent in plants than in fungi, although the effect was statistically significant and strongly pronounced in all species. The effect of K fertilization in reducing 137Cs activity concentration in fungi and plants decreased over time but was still significant in 2009, 17 years after fertilization. This suggests that application of K fertilizer to forests is an appropriate and effective long-term measure to decrease radiocaesium accumulation in plants and fungi.  相似文献   

15.
Mosses and lichens are useful biological indicators of environmental contamination for a variety of metals and radionuclides of both natural and artificial origin. These plants lack a well-developed root system and rely largely on atmospheric deposition for nourishment. Therefore in the study, different lichens (Cladonia convoluta, Cladonia foliacea) and mosses (Homalothecium sericeum, Hypnum lacunosum, Hypnum cupressiforme, Tortella tortuosa, Didymodon acutus, Syntrichia ruralis, Syntrichia intermedia, Pterogonium graciale, Isothecium alopecuroides, Pleurochatae squarrosa) were collected around the Yata?an (Mu?la), Soma (Manisa), Seyitömer - Tunçbilek (Kütahya) coal-fired power plants and investigated for potential use as biomonitors for 210Po and 210Pb deposition. While the activity concentrations of 210Po and 210Pb in lichens are in the ranges of 151 ± 7-593 ± 21 and 97 ± 5-364 ± 13 Bq kg−1, for mosses the ranges for 210Po and 210Pb are 124 ± 5-1125 ± 38 and 113 ± 4-490 ± 17 Bq kg−1, respectively. In the study, the moss samples were observed to accumulate more 210Po and 210Pb compared to lichens. While the most suitable biomonitor was a moss species (H. lacunosum) for Yata?an (Mu?la), it was another moss species (S. intermedia) for Soma (Manisa) and Seyitömer - Tunçbilek (Kütahya) sites. 210Po concentrations were found higher than 210Pb concentrations at the all sampling stations.  相似文献   

16.
Heterogeneity of precipitation could influence various physiological and ecological processes of plants. We present a comparative study on the ecophysiological responses of two congenerous species, Mosla chinensis (an endemic species) and M. scabra (a weedy species), to four soil water content (20%, 40%, 60% and 90% of water holding capacity (WHC), referred to as W20, W40, W60 and W90, respectively) to understand their ecophysiological responses and ecological differentiation. Results showed that both species grew well from W40 to W90, as they showed higher photosynthetic rate and biomass and bigger plants under these soil water content. However, biomass, chlorophyll a to b ratio (Chl a/b) and root to shoot ratio (R/S) of M. scabra but not M. chinensis were significantly reduced under W20, indicating M. chinensis showed stronger capacity of sun-acclimation under severe drought than M. scabra. M. chinensis showed priority in adapting severe drought in comparison with M. scabra. We hypothesize that the different adaptive abilities to soil water content are partly responsible for their ecological differentiation observed in the field and may affect their fate in their native habitat.  相似文献   

17.
Prawn aquaculture industry is one of the developing economic activities in the Philippines. Generally, a wide range of microalgae typically grow and proliferate in many aquaculture ponds. However, certain species of microalgae have the ability to form harmful algal blooms (HABs) which often bring damaging consequences to the aquaculture industry, food safety, and the environment. The study aims to identify and characterize the composition of microalgae (particularly Cyanophyta) that are capable of forming HABs in selected freshwater prawn culture ponds in Central Luzon, Philippines, using morphological, ultrastructural, and molecular characterizations. From water samples collected in ten selected ponds across Central Luzon (Bulacan, Nueva Ecija, Pampanga, Tarlac, and Zambales), potential HAB formers such as Oscillatoria agardhii, O. princeps, Microcystis aeruginosa, and M. wesenbergii were observed to have occurred mostly, while Anabaena circinalis was only observed in one site. Both morphological and ultrastructural methods brought upon some challenges and limitations while molecular methods using 16S rRNA gene and phylogenetic analysis which were optimized in this study offered better and more efficient ways of identification and were helpful in resolving genus-level and species-level relationships. The influence of physicochemical properties of pond water, especially nutrient levels (nitrate, nitrite, and orthophosphate) on the occurrence of these cyanobacteria was also analyzed. As a pioneering study on freshwater HABs in aquaculture ponds in the country, results of the study can provide information to improve the knowledge in bloom occurrence and prediction, and to develop freshwater HAB prevention and control methods.  相似文献   

18.
The response to copper pollution was studied in the vegetative progeny of tufted hair grass (Deschampsia caespitosa (L.) Beauv.) and ragged robin (Lychnis flos-cuculi L.) plants growing together in chronically polluted areas around the Middle Ural Copper Smelter or in background areas. The root elongation test was used, with copper sulfate (0.006–0.51 mg Cu/L) being added directly to the nutrient medium. Using multimodel inference, dose-response curves were plotted for each of 85 maternal plants, and their parameters (effective Cu concentrations and curve slope in the linear segment) were evaluated. The pattern of transformation in dose dependence of root increment upon transition from background to impact populations proved to be basically different in the two species. The curves for L. flos-cuculi showed a parallel shift, with their shape remaining generally unchanged. In D. caespitosa, this transition was accompanied by a decrease in sensitivity to Cu, but tolerance to this metal was found to increase only at the highest concentration range. These results provide evidence for different strategies of adaptation to heavy metal pollution, which are discussed by comparing the physiological and ecological properties of the two species.  相似文献   

19.
Analyses of Umbilicaria species collected from southwest Poland in August 1986 have shown there to be significant increases in levels of various radionuclides since previous analyses based on fieldwork in 1978–1979. The composition and ratio of the various radionuclides, particularly in respect of 134Cs and 137Cs, exhibit a characteristics signature consistent with contamination derived from the accident at the Chernobyl nuclear reactor in April 1986. Intraspecific variation in levels of 137Cs in Umbilicaria is related to such factors as location, altitude and, to a lesser degree, aspect; interspecific variation in levels is related to ecological requirements and geographical pattern, and hence the same factors, although morphological differences in thalli may be implicated.  相似文献   

20.
The abundance of Orchidaceae on three calcareous grasslands is studied in relation to floristic composition, environmental and vegetational factors and plant traits (ecological and life forms). The aims are: (i) to identify a group of species that is significantly correlated with the abundance of Orchidaceae or with individual species of orchids on calcareous grasslands; (ii) to study the relationship between traits associated with habitat specialisation, community life forms and the abundance of orchids; (iii) to identify the main environmental and vegetational predictors of the abundance of orchids. A shortlist of species is found to be significantly correlated with the abundance of total orchids, Orchis pauciflora and O. morio. The life forms of the community species do not show any correlation with the orchids, with the exception of Orchis pauciflora, which tends to increase in communities rich in hemicryptophytes and poor in annual species. Analyses of Orchis morio seem to suggest that it has a high level of ecological tolerance. The most important predictors of the abundance of orchids are the substrate reaction (basic) and arid grassland with low herbaceous vegetation cover (i.e. high soil reaction and luminosity values, positive correlation with the cover of lichens and rockiness, negative correlation with tree cover and herbaceous layer). The least favourable sites were the least basic and most superficial and arid sites.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号