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1.
Depending on the species, Cryptocoryne plants grow in different biotopes, viz. spring, river, dark forest, and tree-savanna. The species of Lagenandra are exclusively found in river biotopes. The chromosome numbers found in this study corroborate the numbers previously recorded. Some variation in respect to the morphology of the inflorescence of C. wendtii de Wit and L. ovata (L.) Thwaites is described. A map presenting the distribution of the of Cryptocoryne with their chromosome numbers is included.
The existing populations of Cryptocoryne on Sri Lanka should be protected from further exploitation by plant collectors.  相似文献   

2.
Numerous natural foci of leptospirosis infection in which Ap. sylvaticus and M. musculus play the role of the main source, were found on the territory of the north-eastern part of Azerbaijan's east mountain range. The leading place in the aetiological structure of leptospirosis of small mammals is occupied by leptospirae of the serological group Hebdomadis. As a rule, the animals -- Leptospira-carriers -- populate damp biotopes where stable natural foci of disease are formed. Two types of natural foci were established on the given territory, i. e., the marshy-bush type and the mountain-stream type. The foci are characterized by several hosts and several serotypes of Leptospira.  相似文献   

3.
Land reclamation measures carried out on the territory of a flood-plain-paludal focus of tularemia change the ecological and biocenotic links, which leads to the formation of a meadow-field focus with other-than-before sources and vectors of tularemia infection.  相似文献   

4.
The diversity and spatial distribution of vascular epiphytes were surveyed in two biotopes (dryland forest and swamp-inundated forest) of the semi-deciduous rain forest area in Cameroon. Eight sites in each biotope were selected, which included 530 individuals of phorophytes in dryland forest and 460 in swamp-inundated forest. A total of 148 epiphyte species were recorded, which showed that semi-deciduous rain forests represent a major source of African-epiphyte diversity. Dryland forest hosted 110 epiphyte species, while the swamp-inundated forest harboured 108. A total of 56 species were found only in the dryland forest and 60 were restricted to the swamp-inundated forest. At family level, Orchidaceae exhibited the highest-species richness within both biotopes. Pteridophytes were more abundant in the swamp-inundated forest. A TWINSPAN analysis of the floristic similarities separated the two investigated forest types very clearly. No significant difference existed between the two biotopes regarding vertical distribution of epiphytes within single trees. The swamp-inundated forests may serve as a refuge for many epiphytes that occur in the outer canopy of the dryland forests, both because they are inherently less vulnerable to timber extraction, and enjoy better protection by legislation.  相似文献   

5.
The natural foci of the Congo-Crimean hemorrhagic fever (CCHF) in Ukraine were characterized by their geographical factors. The circulation of CCHF virus was found to occur mainly in forest and forest-steppe zones irrespective of the location of administrative regions. The territories found to be most favorable for the prolonged existence of the focus of CCHF were those having high humidity. The possibility of using geoinformation technologies for the correction of the boundaries of natural foci, the evaluation of the influence of geographical factors on the circulation of the virus was shown.  相似文献   

6.
The specific composition of gamasid mites from three species of voles (Microtus arvalis Pall., M. agrestis L., M. oeconomus Pall.) is given. Forest, field and flood-land groupings of the common vole having distinct phenotypical differences are characterized by differences in the structure of their parasite fauna. In the forest the number of meadow and meadow-field species decreases while that of forest species of mites regularly increases.  相似文献   

7.
The main penetration route of cryptosporidia oocysts (at the infective stage) from animal carriers in the natural ecosystems of the forest zone into the environment of human habitat has been newly established. Oocysts excreted with feces are concentrated in the surface layer of the soil, then washed into water reservoirs. The viability of oocyts from the soil and the silt of river sand banks and shallows has been experimentally shown. As a result, the natural foci of cryptosporidiosis have been found to play an important role in the supply of infective agents to rivers serving as sources of water supply. From epidemiological viewpoint natural ecosystems are comparable with cattle-breeding farms and pastures. Humans run a real risk of being infected during visits to a forest.  相似文献   

8.
This article focuses on assessing the habitats characteristics of endangered Calamagrostis pseudophragmites in selected localities in the Czech Republic with different river engineering measures, which can potentially influence the occurrence of this species. Furthermore, we give some general recommendations for management practices based on our results to promote the conservation of Calamagrostis pseudophragmites.Our research shows that there is a high correlation between Calamagrostis pseudophragmites and natural or near natural sunny biotopes on gravel bars or straight reaches near the water level that consist of non-silted gravel substrates with a higher concentration of pebbles or cobbles, which are typical of piedmont and mountain-valley areas. Many of these areas are rapidly disappearing due to intensive anthropogenic pressure. We also found that Calamagrostis pseudophragmites is temporarily capable of surviving among other competitively stronger plant communities.To assess the potential influence of river engineering we selected two different types of rivers where this species is present – one was heavily altered by both the construction of a water reservoir in its upper reach and channelization of the stream, the other was less severely regulated by the construction of several weirs. Our results show differences in the occurrence of Calamagrostis pseudophragmites between the two rivers, being found at three times as many localities in the less regulated river than in the more regulated one. This corresponds with a higher number of gravel bars in the less regulated river.Based on our results, our general recommendations for the management of this species include only the partial removal of gravel bars (to ensure flood control in populated areas), blocking vegetation succession by removing woody vegetation and aggressive invasive species, the restoration of natural river dynamics, and connecting existing biotopes where this species is found.  相似文献   

9.
A consensus has been established that functional traits rather than taxonomic diversity play a fundamental role in linking biodiversity with ecosystem processes and associated services. This study from Finland addressed an issue of relative values of fallow and field margin biotopes in conservation of plant functional diversity (based on six functional traits of relevance to ecosystem services, and diversity of multiple traits) in agricultural landscapes differing in their structural complexity. Relative covers of plant species were surveyed in sampling plots located in perennial fallow fields and three types of perennial margins (margins between crop fields, along forest edges and by river) in three types of landscape context (simple, intermediate and complex). Fallow fields significantly contributed to the total functional diversity only in simple landscapes. The river margins provided the greatest functional diversity, especially in reproduction and regeneration traits while crop margins were consistently characterized by the lowest functional diversity. Substantial functional diversity of fallow patches in simple landscapes was due to high abundance of functional species, while that of river margins stemmed from presence of unique species. The plant functional diversity progressively declined with agricultural landscapes becoming simplified. The study indicates non-cropped biotopes having complementary roles in ensuring multifunctionality of agro-landscapes and confirms importance of biotope mosaic for functional diversity.  相似文献   

10.
The analysis of archaeological charcoal is used to reconstruct the wood resources in north-west Portugal from the late Bronze Age to the Roman period. In this paper, the results obtained from 12 sites are considered, and their implications for interpreting historical human behaviour towards the natural environment and vegetation are discussed. The results indicate a similar kind of exploitation of the vegetation by different populations which used a similar range of wood resources. Fifty-one taxa are identified and three main natural biotopes are distinguished, including mixed oak forest, wasteland vegetation and riparian forest. The large number of taxa identified seems to testify to the existence of a good sampling of the woody vegetation growing in the proximity of the settlements. Both dry and fresh wood were used, and the value and possible uses are suggested for some of the most frequent taxa identified.  相似文献   

11.
Plant, spider, beetle, and ground beetle communities were studied in different agrolandscape biotopes (a wheat field, a field margin, and a forest belt) of Krasnodar Territory. In these biotopes, borders between plant communities were distinct. On the contrary, arthropod communities were not usually confined to the certain biotopes. The high degree of mobility of arthropod species resulted in a decrease in their association with the biotope. Representatives of some species (especially, beetles) were revealed in all the biotopes. In relation to season and some other factors, they frequently concentrated in different biotopes. Analysis of arthropod assemblages only within a single biotope gives us a rather impoverished knowledge of the whole population. It is necessary to study these assemblages not only within the basic biotope, but also in adjacent ones.  相似文献   

12.
We investigated the genetic structure within and among Bornean orang-utans (Pongo pygmaeus) in forest fragments of the Lower Kinabatangan flood plain in Sabah, Malaysia. DNA was extracted from hair and faecal samples for 200 wild individuals collected during boat surveys on the Kinabatangan River. Fourteen microsatellite loci were used to characterize patterns of genetic diversity. We found that genetic diversity was high in the set of samples (mean H(E) = 0.74) and that genetic differentiation was significant between the samples (average F(ST) = 0.04, P < 0.001) with F(ST) values ranging from low (0.01) to moderately large (0.12) values. Pairwise F(ST) values were significantly higher across the Kinabatangan River than between samples from the same river side, thereby confirming the role of the river as a natural barrier to gene flow. The correlation between genetic and geographical distance was tested by means of a series of Mantel tests based on different measures of geographical distance. We used a Bayesian method to estimate immigration rates. The results indicate that migration is unlikely across the river but cannot be completely ruled out because of the limited F(ST) values. Assignment tests confirm the overall picture that gene flow is limited across the river. We found that migration between samples from the same side of the river had a high probability indicating that orang-utans used to move relatively freely between neighbouring areas. This strongly suggests that there is a need to maintain migration between isolated forest fragments. This could be done by restoring forest corridors alongside the river banks and between patches.  相似文献   

13.
This paper studies the impact of a free-ranging bison population on the vegetation and soil fauna in spatially adjacent biotopes (meadow-transition zone-surrounding forest) in the Kaluzhskie Zaseki State Nature Reserve. It is noted that bison maintains meadows in the absence of haymaking. Analysis of phytosociological relevés shows that the forest vegetation has been significantly transformed by bison over 10–15 years, as evident from (1) differences in the ecological-coenotic structure of the vegetation in the different biotopes, (2) a larger ecological-coenotic diversity of communities in the transition zones in comparison with surrounding forests, and (3) an increase in the participation of nitrophilous species in the vegetation. A fairly high earthworm species diversity (a total of seven species in the biotopes) is found; Aporrectodea caliginosa dominates in the earthworm density and biomass. The total earthworm density and biomass became lower in the transition zone than in neighboring forests and meadows, and the differences in earthworm density between the transition zone and the meadows were statistically significant.  相似文献   

14.
长爪沙鼠的一些生态学资料   总被引:4,自引:3,他引:4  
长爪沙鼠(Meriones unguiculatus)是荒漠草原分布较广的害鼠。夏武平(1982)、赵肯堂(1960)等对长爪沙鼠的某些生态方面进行了研究。作者从1979年5月至1980年6月在宁夏陶乐县对长爪沙鼠的数量季节变动、迁徒、繁殖、年龄组成、食性等方面进行了调查研究,现报告于后。  相似文献   

15.
E. N. Pavlovski?'s concept of natural focality of diseases and the development of general knowledge about natural foci and their structural (components), functional (mechanisms of pathogen maintenance), and ecosystem-related organization (assortment and interrelations of ecosystems) are reviewed from principal (in authors' opinion) aspects. The 60-year history of this theory includes three stages at which its scope and contents differed. At the first stage, it concerned transmissible zoonoses. It had been assumed that structurally, natural foci necessarily include the pathogen-vector-host triad, and the functioning of the focus is provided for by only pathogen circulation in terrestrial ecosystems. At the second stage, it became clear that vector is not a necessary structural component of any focus (an example of nontransmissible diseases), although the functioning of foci remained to be unequivocally attributed to the continuous pathogen circulation among animals of terrestrial ecosystems. The third stage is characterized by an understanding that, in general, the presence of a warm-blooded host in the focus is also unnecessary for pathogen survival, and natural foci can be represented by soil and aquatic ecosystems. The only necessary and specific component of any natural focus is the pathogen population. In this context, modern views on natural focality of diseases are reviewed, and the essence of the terms "natural focus" and "epizootic process" is defined. It is proposed to distinguish the phases of pathogen reservation and epizootic spread (circulation) in ecosystems of any type. The current state of this concept provides evidence that, in general biological terms, studies on natural focality of diseases belong to one of the fields of symbiotology.  相似文献   

16.
Search for natural foci of leptospirosis was carried out in 1987-1989 in humid biotopes of Tashauz Province, Turkmenistan. Such potential carriers of leptospirosis as house mice (Mus musculus) and tamarisk gerbils (Meriones tamariscinus) are widely spread in this area, and the size of their population can amount to great numbers. The sharpest fluctuations in the population size are characteristic of house mice inhabiting the shores of water collecting ponds and lakes in the regions of minimally used pastures. A moderate number of house mice was registered in spring and autumn at the area of irrigated agriculture. Only here and only in autumn a faint epizootic manifestation of the natural focus of L. grippotyphosa infection in house mice was registered for the first time in Turkmenistan. The titers in mouse blood sera, determined in the microagglutination test and the Leptospira lysis test, were 1:20 to 1:200. According to the data on the humidity and pH of the soil in the vicinity of irrigated fields, spring and summer months may be regarded as the most favorable period for the survival of leptospires in the environment. The probability of the aggravation of the epizootic situation seems to increase when irrigated fields adjoin pastures of are temporarily used as grazing ground for cattle.  相似文献   

17.
The millipede Pycnotropis epiclysmus Hoffman, 1995 (Diplopoda: Polydesmida: Platyrhacidae) is frequently found in Central Amazonian white-and mixed-water inundation forests along the Solimöes-Amazon River near Manaus, Brazil. It also inhabits non-flooded disturbed forest areas adjacent to this river. Populations from both biotopes were genetically studied. The specific pPeP172 satellite DNA family identified in P. epiclysmus has been analyzed in order to elucidate the systematic rank of morphologically indistinguishable individuals from the different habitat types. Nucleotide sequence data, sequence variability and copy number estimates of the pPeP172 satellite DNA do not discriminate the respective populations into genetically different ecotypes. The study of enzyme variability, however, revealed genotypic differences among the three populations: the populations from two geographically more distant inundation forests are genetically rather similar; and the geographically closer populations, one found in a non-flooded and the other in an inundation forest, have a genetic distance which is of similar magnitude to that of the two geographically more distant populations. The genetic data suggest that individuals from different habitats belong to populations of a single species. Genotypic structuring among and within local populations indicates processes of genetic differentiation which can be the result of the migration ability of this millipede.  相似文献   

18.
Dermacentor reticulatus is the second most important tick species in Poland. Although the north-eastern region of Poland is considered typical for D. reticulatus and is treated as a contiguous area of Eastern populations of the meadow ticks, the occurrence of this tick species in this region to date has been recorded as separate foci. The present report supplements data on the geographical distribution of D. reticulatus in urban and natural biotopes of north-eastern Poland (Warmia and Mazury province). In 2015–2017 (during the springtime activity of ticks) adult questing D. reticulatus were found in 13 of 25 monitored localities. Six sites are located in urbanized areas, within the administrative borders of the city of Olsztyn and seven sites are in natural biotopes in the central part of Warmia and Mazury. A total of 398 adult D. reticulatus ticks, including 257 females and 141 males, were collected. A comparison of data grouped according to urban and natural type of area revealed no statistical differences between them. Taking into account the habitat type, the mean tick density was the highest in open landscapes. The identification of new foci D. reticulatus in the endemic areas of Lyme borreliosis, tick-borne encephalitis and canine babesiosis is crucial for determining the risk of diseases transmitted by ticks and taking proper preventive measures.  相似文献   

19.
Putchkov A 《ZooKeys》2011,(100):503-515
A review of the ground beetles of the Ukrainian fauna is given. Almost 750 species from 117 genera of Carabidae are known to occur in the Ukraine. Approximately 450 species of ground beetles are registered in the Carpathian region. No less than 300 species of ground beetles are found in the forest zone. Approximately 400 species of Carabidae present in the forest-steppe zone are relatively similar in species composition to those in the forest territories. Some 450 species of Carabidae are inhabitants of the steppe zone. Representatives of many other regions of heterogeneous biotopes such as forest, semi desert, intrazonal, etc. can be found in the steppe areas. The fauna of Carabidae (ca. 100 species) of the lowlands of southern Ukraine (sandy biotopes), situated mostly in the Kherson region, is very peculiar. The fauna of the Crimean mountains contains about 300 species. Conservation measures for the Carabidae are discussed.  相似文献   

20.
Populations of the land snail Cepaea nemoralis have been investigated at the southern limits of its range in Spain, the Upper Tajo region, in order to analyse the distribution of the species and the variation of polymorphism in relation to environmental conditions. For this purpose two natural subareas, which differ in topography, soil nature, climate and vegetation have been considered. Cepaea nemoralis is confined to the river banks of the area; it is found in open and shaded biotopes of subarea 1 where it is relatively common, and it is almost restricted to shaded biotopes of subarea 2 where it becomes progressively rarer towards the south. Relative abundance of the species may be related to the amount of calcareous soils and climate, the restriction in its southern distribution being probably the result of extreme solar radiation, high temperature and low humidity. The two subareas differ in the frequency of the main polymorphic characters. These differences may be related to the kind of biotope. Subarea 1 richer in more open and exposed biotopes have higher frequencies of yellow, 00000, 00300, and unfused bands, whereas the restriction to poplar groves because of the lack of suitable exposed biotopes in subarea 2 may account for the higher proportion of pink five-bandeds with the bands fused together. This kind of variation with biotope is consistent with an explanation in terms of differences in the temperature absorbance of different morphs and a metabolic response to differences in temperature amplitude of the biotopes. Other characters (lip colour, punctate bands, hyalozonate bands, etc.) are not polymorphic in this region, thus, suggesting that at the periphery environmental conditions are important not only in determining the distribution of the species but exerting a marked effect on the genetic structure of the populations.  相似文献   

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