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 15 毫秒
1.
The Asian bush mosquito, Aedes japonicus japonicus, and the coastal rock pool mosquito, Aedes togoi, are potential disease vectors present in both East Asia and North America. While their ranges are fairly well‐documented in Asia, this is not the case for North America. We used maximum entropy modeling to estimate the potential distributions of Ae. togoi and Ae. j. japonicus in the United States, Canada, and northern Latin America under contemporary and future climatic conditions. Our results suggest suitable habitat that is not known to be occupied for Ae. j. japonicus in Atlantic and western Canada, Alaska, the western, midwestern, southern, and northeastern United States, and Latin America, and for Ae. togoi along the Pacific coast of North America and the Hawaiian Islands. Such areas are at risk of future invasion or may already contain undetected populations of these species. Our findings further predict that the limits of suitable habitat for each species will expand northward under future climatic conditions.  相似文献   

2.
New data on morphology and differential diagnosis of adults (variability of the pattern of mesonotum and wings, difference from all other species of the cantans group of the Palaearctic fauna by the spot of the scales on the mesepimeron reaching its lower edge, difference of its male genitalia from those of Ae. montchadskyi Dub.), biology (period of activity and predomination indices of the females attacking man, breeding places and period of occurrence of preimaginal phases in the south of the East Transbaikalia and Krasnoyarsk Region), and geographical distribution (from the Tuva ASSR and south of Krasnoyarsk Region in the west to the south of the Chita Region in the east, misidentification in East Kazakhstan, confinement of the range to the Mongolian district of the Kazakhstan-Mongolian province of the Central Asian subregion of the Holarctic that suggests that the main part of its distribution range is situated in Mongolia) are given for the recently described species of mosquitoes, Aedes sergievi Danilov, Markovich et Proskuryakova, 1978 from the south of East Siberia.  相似文献   

3.
In this study we revise the biogeographic delimitation, and large-scale patterns of community structure of the intertidal rocky shores of southern Africa. We use binary (presence/absence) and per-species biomass data collected at fifteen localities and thirty-seven different rocky sites, encompassing the shores of southern Namibia, South Africa and southern Mozambique. Multivariate analyses revealed that the shores of southern Africa (south of 25°) can be divided into three main biogeographic provinces: the west coast or Namaqua province, the south coast or Agulhas province and the east coast or Natal province. The biomass structure of the intertidal rocky shores communities of southern Africa varied at a large scale, corresponding to biogeographic differences, while local-scale variation accorded with the intensity of local wave action. The average biomass of west coast communities was on average significantly greater than that of the south and east provinces. At a local scale, the community biomass on exposed shores was an order of magnitude greater than on sheltered shores, within all biogeographic provinces. Semi-exposed shores exhibited intermediate average biomass. The trophic structure of these communities varied significantly with wave action: autotrophs, filter-feeders and invertebrate predators were more prevalent on wave exposed than sheltered shores, whereas grazers were more abundant on sheltered and semi-exposed shores. Exposed shores were consistently dominated by far fewer species than semi-exposed and sheltered shores, independently of biogeographic differences. Within all biogeographic provinces semi-exposed and sheltered shores were more diverse than exposed shores. West coast intertidal communities therefore had high levels of biomass, but were consistently species-poor. Several working hypotheses that could explain these large and small-scale patterns are presented.  相似文献   

4.
Diversity and biogeography of southern African intertidal Acari   总被引:1,自引:0,他引:1  
Abstract Aim The aims were (1) to describe the diversity and geographical distribution of the intertidal mite fauna of southern Africa, and (2) to show how species richness, endemism and geographical patterns of this fauna (comprising taxa of variable terrestrial ancestry) compare with typically marine faunas. Location and methods To assess intertidal mite diversity and endemism, records (published and unpublished) were compiled for a variety of habitats (mainly rocky shores and mangroves), between Swakopmund (Namibia) and Inhambane (Mozambique). The geographical study was based on a dedicated sampling programme from rocky shores, at nine localities between Elandsbaai (on the west coast) and St Lucia (on the east coast). Results Eighty‐two species of marine mite, from thirty‐three genera, are currently known from southern Africa. The majority belong to the earlier marine ancestral Halacaridae (forty‐eight species), with the Ameronothroidea and Hyadesiidae collectively comprising seventeen species. In constituting three faunistic provinces, corresponding with the west (Atlantic), south and east coast (Indian) regions, the mite fauna conforms with trends for the southern African marine fauna in general. Species richness was greatest in the southern province, which deviates from the general pattern of increase from west to east, but is similar to that of some invertebrate taxonomic groups. Conclusions Despite their relatively recent marine connections, marine mites show typical geographical distributions, comparable with those of other rocky‐shore biota in southern Africa. The marine faunistic provinces are ‘insular’ and apparently remain largely intact, across taxonomic groups and with increased taxonomic resolution.  相似文献   

5.
The Lebanon Lizard (Phoenicolacerta laevis) occurs on the Levantine coast and scattered populations are found in isolated coastal habitats along the southern and south-western coast of Turkey. We found an isolated but dense population of this species at and around the castle of Anaklia on Georgia’s Black Sea Coast, near the mouth of the river Enguri. The analysis of mitochondrial cytochrome b sequence suggests closeness of this population to the populations in the provinces of Kahramanmara?, Adana and Içel in southern Turkey, rather than to those in Lebanon and Israel. It is thought that the species was introduced from a Turkish region to Anaklia, which was an important trade location at the eastern Black Sea coast until the late 18th century. This is the first established location of this species outside the eastern Mediterranean area. Climate and competition with rock lizards of the genus Darevskia are the most likely reasons preventing expansion of the species into the neighboring areas of Western Georgia.  相似文献   

6.
Recently three biogeographical units were identified along the Chilean coast (the Magellanic Province, an Intermediate Area, and the Peruvian Province), however few studies have focused on the factors and dynamic processes that formed these spatial units (e.g. Rapoport's rule and its causal mechanisms). In this study we used benthic polychaetes of the Chilean coast to evaluate patterns of latitudinal distribution and species richness, and the existence of the three main biogeographical provinces described for the Chilean coast. Additionally, we evaluated the latitudinal Rapoport effects and geometric constraint as a null hypothesis explaining the species richness distribution.
We found that benthic polychaete diversity increased towards southern latitudes. The cluster and ordination (non-metric MultiDimensional Scaling, nMDS) analyses of the distribution data, presented only two statistically significant (bootstrapping techniques) biogeographic provinces along the Chilean coast, with a break occurring between 41° and 42°S. While, our results did not support a latitudinal Rapoport effect, they did support the view that latitudinal Rapoport effects are a local phenomenon, occurring only for the Northeastern Pacific marine taxa. The relationship between latitudinal range extent and mean latitude indicated the existence of two hard boundaries at either extreme of the Chilean coast, limiting the geographical ranges of the species. However, geometric constraints tested using a Monte Carlo simulation approach showed a weak level of mid-domain effect on species richness. Finally, we propose that geometric constraint together with the geomorphology and historical characteristics of the Chilean coast explain the biogeographical patterns of benthic polychaete taxa in Chile.  相似文献   

7.
黄土高原子午岭种子植物区系特征研究   总被引:14,自引:0,他引:14  
黄土高原子午岭位于黄土高原中部半湿润半干旱过渡带(107°30′~109°40′E,33°50′~36°50′N)。其在植被分区上隶属于泛北极植物区、中国-日本森林植物亚区的华北地区黄土高原植物亚地区。区内共有种子植物94科361属689种,分别占黄土高原区种子植物总数的63.95%、41.78%和21.37%。其中大科、大属在区系组成中起着非常重要的作用。该区种子植物属包含15个分布区类型及12个变型,其中北温带分布、旧世界温带分布、泛热带分布、东亚分布等成分占有重要地位。其种子植物区系的基本特征是:植物种类相对丰富;多种地理成分交汇、过渡特征明显;区系组成以华北成分为主体,温带成分占优势;沿纬度梯度地理成分差异显著,垂直分布带谱不明显;区系成分新老并存,特有化程度低。  相似文献   

8.
Aim To investigate the biogeographical structure and affinities of the Australian marine demersal ichthyofauna at the scale of provinces and bathomes for the purposes of regional marine planning. Location Australia. Methods Patterns of distribution in the Australian fish fauna, at both intra‐regional and global scales, were examined using a science‐based, management framework dividing Australia’s marine biodiversity into 16 province‐level biogeographical units. Occurrences of 3734 species in eight depth‐stratified bathomes (from the coast to the mid‐continental slope) within each province were analysed to determine the structure and local affinities of their assemblages and their association with faunas of nearby regions and oceans basins. Results Strong geographic and depth‐related structure was evident. Fish assemblages in each province, and in each bathome of each province, were distinct, with the shelf‐break bathome more similar to the adjacent continental shelf bathome than to the upper slope bathome. Data based only on endemic species performed well as a surrogate of the entire dataset, yielding comparable patterns of similarity between provinces and bathomes. Tropical and temperate elements were better discriminated than elements of the Pacific and Indian oceans, with the central western province more similar to the tropical provinces (including those in the east), and the eastern province closer to southern temperate provinces. The fauna shares the closest regional affinities with those of the adjacent south‐west Pacific, western Pacific Rim, and elements of wide‐ranging Indo‐Pacific components. Elements unique to the Pacific and Indian oceans are poorly represented. Main conclusions The complex nature of Australia’s marine ichthyofauna is confirmed. A hierarchy of provinces and bathomes, used to ensure that Australia’s developing marine reserve network is both representative and comprehensive, is equally robust when based on all known Australian fish species or on only those species endemic to this continent. Latitude and depth are more important than oceanic influences on the composition of this fauna at these scales.  相似文献   

9.
A total of 158 Aegilops-Triticum samples representing six Aegilops species (one diploid, four tetraploid and one hexaploid) and one diploid Triticum were collected along the Bulgarian Black Sea coast, and their distribution on the 350 km long coastal line was reported. The region south of Kamchia river, accepted as the middle point of the coast, was characterized by the greatest diversity of these wild relatives of wheat. The most widely distributed species in this area was Ae. geniculata. Ae. cylindrica was distributed only in north (Durankulak), while Ae. biuncialis and Ae. triuncialis were collected both north and south of Kamchia river. All samples of Ae. neglecta were hexaploid. Natural hybrids of goatgrass and wheat were found in Ae. cylindrica populations. Triticum monococcum ssp. aegilopoides had limited distribution in the south region. Aegilops uniaristata was recorded as a new species for the Bulgarian flora. Most of the samples expressed resistance to powdery mildew in seedling and adult stage, but all of them were polymorphic regarding the resistance to leaf rust (cultures 73760 and 43763). The study revealed additional data for the distribution of Aegilops and Triticum species in Bulgaria and their potential value as genetic resources in wheat improvement.  相似文献   

10.
Aedes albopictus (Stegomyia albopictus) (Diptera: Culicidae) has probably supplanted Aedes aegypti (Stegomyia aegypti) throughout most of its historical range in the U.S.A., although Ae. aegypti still exists in large coastal cities in southern Florida. We measured salt concentrations in field containers along an axis perpendicular to the coast and examined intraspecific outcomes in these species under different salt concentrations in a factorial study using varying intra‐ and interspecific densities in different conditions of salinity to order to determine if salt could mitigate the documented competitive superiority of Ae. albopictus. Salt in field containers declined away from the coast, with maximal values similar to our lower salt concentrations. Egg hatching and short‐term survival of pupae and late instars were not affected by salt concentrations; survival of early instars of both species decreased at higher concentrations. In high salt conditions, Ae. aegypti achieved higher survival. In the longterm experiment, both species displayed longer development times. Salt did not affect interactions for either species; Ae. aegypti survived in the highest salt conditions, regardless of density. The tolerance of Ae. aegypti to high salt concentrations may allow it to use coastal containers, although because salt did not mediate interspecific interactions between Ae. aegypti and Ae. albopictus, the ultimate effects of salt on the coexistence of these species or exclusion of either species remain unknown.  相似文献   

11.
Aim To describe the biogeography of the ascidian fauna of southern Africa, to compare the results obtained with those reported for other fauna and flora of the same region, and to speculate about the origin of ascidians in the region. Location Southern Africa extending over 4000 km from Mossâmedes (15° S–12° E) to Inhaca Island (26°30′ S–33° E), including Vema Seamount (31°40′ S–8 °20′ E), Amsterdam‐Saint Paul Islands (38° S–77°30′ E) and the Tristan‐Gough Islands (38° S–12°20′ W). Methods We constructed a presence/absence matrix of 168 species for 26 biogeographical divisions, 21 classical biogeographical regions described by Briggs (Marine zoogeography, McGraw‐Hill, New York, 1974) and five provinces within the southern African region. We considered the following limits and divisions into provinces for the southern African region: Namibia, Namaqua, Agulhas and Natal as proposed by Branch et al. (Two oceans. A guide to the marine life of southern Africa, David Philip Publishers, 1994), and the West Wind Drift Islands province (WWD) according to Briggs (Global biogeography, Elsevier Health Sciences, Amsterdam, 1995). To examine the biogeographical structure, species and divisions were classified using cluster analysis (based on UPGMA as the aggregation algorithm) with the Bray–Curtis index of similarity. This classification was combined with MDS ordination. Main conclusions Four main groups were obtained from the analysis of affinities among species: (1) species present in the WWD, separated by a high percentage of endemisms and a low number of species with a southern African distribution. Moreover, in the light of the species distribution and the results of further analysis, which revealed that they are completely separated and not at all related to the southern African region, it appears that there are no close relationships among the different islands and seamounts of the West Wind Drift Island province. This province was therefore removed from the remaining analyses; (2) species with a wide distribution; (3) species of colder waters present in Namaqua and Agulhas provinces, a transitional temperate area in which gradual mixing and replacement of species negate previous hypotheses on the existence of a marked distributional break at Cape of Good Hope; (4) species of warmer waters related to Natal province. The classification into biogeographical components was dominated by the endemic (47%), Indo‐Pacific (25%) and cosmopolitan (13%) components. The analysis of affinities among biogeographical areas separated Namibia from the rest of the southern African provinces and showed that it was related to some extent to the Antarctic region because of the cold‐temperate character of the province and the low sampling effort; Namaqua, Agulhas and Natal were grouped together and found to be closely related to the Indo‐West Pacific region. In general, our results were consistent with those obtained for other southern African marine invertebrates. The frequency distribution of solitary/colonial strategies among provinces confirmed the domination of colonial organisms in tropical regions and solitary organisms in colder regions. Finally, we speculate that the southern African ascidian fauna mainly comprises Indo‐Pacific, Antarctic and eastern Atlantic ascidians.  相似文献   

12.
甘肃裸子植物区系地理分析   总被引:6,自引:0,他引:6  
在对甘肃产裸子植物进行系统整理的基础上,探讨了甘肃裸子植物的区系特征和区系分区。甘肃裸子植物种类丰富,产5科15属45种。其特点是:松柏类发达;北温带分布型属和中国特有种占优势;富含第三纪残遗成分;区系乱分具明显交汇过渡性质。依据甘肃各区域生态地理因子分异特点和裸子植物地理分布规律,将甘肃裸子植物区系划分为5个自然的区系小区:走廊区、中部小区、甘南小区、陇南小区。  相似文献   

13.
我国胡椒属植物区系地理研究   总被引:1,自引:0,他引:1  
胡椒属(Piper)为胡椒科(Piperaceae)重要的泛热带组成成分,约有1 000 ~2 000个植物种类,中国是其天然分布的北缘.本文对我国产胡椒属植物区系地理进行了分析,揭示其区系特征、物种起源和散布途径等.结果表明:云南是我国胡椒属植物的重要分布地,并以此为中心向我国东部和北部扩散,物种数量逐渐减少.各省胡椒属物种组成相似性较低,大致可被聚为热带地区、亚热带地区和台湾地区3大分支.在区系成分上,国产胡椒属植物中的中国特有比例最高,其次是热带亚洲分布,只有个别种为泛热带分布和东亚分布.我国胡椒属区系与中南半岛、印度半岛及爪哇群岛存在一定联系,但并不紧密.分析认为,云南是胡椒属植物的起源中心或分化中心之一,而中国台湾岛种类主要由菲律宾群岛等传入并分化.本结果对于研究该属系统分类和起源演化将具有一定意义.  相似文献   

14.
Cluster analysis and species abundance plots of radiolarian abundance counts from core tops from the eastern Indian Ocean between 12° S and 31° S, and the southern Indian Ocean between 31° S and 62.5° S, demonstrate the existence of environmentally-related provinces supporting distinct taxa assemblages. These provinces are closely associated with currents in the eastern sector of the Indian Ocean and with fronts in the southern sector.The radiolarian assemblages correlate strongly with salinity-normalised total alkalinity (NTA) at the sea-surface, with temperature, salinity, and density from the sea-surface to 300 m, and with dissolved oxygen and nitrate and phosphate concentrations from the sea-surface to 100 m. Palaeo-reconstructions of these parameters at the sea-surface have been made for six Last Glacial Maximum (LGM) samples from five eastern Indian Ocean cores. The LGM sea-surface temperature estimates are comparable with those based on planktonic foraminiferal counts of the same samples obtained by other researchers. The reconstructions show that, since the LGM, density increased markedly along the Western Australian coast south of 20° S but changed little further from the Western Australian coast. By contrast, phosphate concentrations were marginally lower than modern values along the Western Australian coast south of 20° S but more than twice modern values in the other LGM samples.The utility of various regression and calibration techniques is discussed. It is concluded that, probably due to the effects of differences in radiolarian habitat, ocean currents, and/or environmental gradients, only one method, weighted averaging — partial least squares, is reliable in a study area of this size and complexity. If other methods are to be used, the study area must be partitioned into at least two separate regions with the major split between the eastern and southern sectors of the Indian Ocean.  相似文献   

15.
中国近海共有海牛亚目(Doridacea)软体动物136种,隶属于23科49属,主要分布在浙江以南的热带、亚热带海区,有些种类向北可以分布到黄、渤海,少数种类仅分布于黄、渤海,属于印度-西太平洋区的中国-日本亚区。  相似文献   

16.
This study concentrates on the speciation and distribution patterns of some heavy metals (Pb, Ni, Cd, Zn, and Cu) in surface sediments in the southern part of the Caspian Sea, the biggest lake in the world, to obtain an overall classification for the origins of metals in the area using a sequential extraction technique. At all sampling stations, Pb, Ni, Zn, and Cu were mostly (>50%) accumulated in the resistant fraction, which indicated that there were no significant anthropogenic inputs of Pb, Ni, Zn, and Cu into the surface sediments of the south Caspian Sea. Guilan province on the west coast of Caspian Sea accumulated higher percentages of non-resistant fractions of Pb and Zn, while Mazandaran and Golestan provinces in the middle and western parts of the Caspian Sea, in the Iranian zone, accumulated higher percentages of non-resistant fractions of Ni and Cu. The present study revealed that the coastal area of the south Caspian Sea is still not seriously contaminated. Cadmium in Guilan and Golestan provinces were dominated by non-resistant fractions (55–69%), which indicated more anthropogenic inputs of Cd on the south coast of the Caspian Sea in comparison with other metals.  相似文献   

17.
Some species are very difficult to observe in the wild, and some of these present an apparently incongruent distribution, as is the case of the spur-thighed tortoise Testudo graeca in the southern Iberian Peninsula. This species has a discontinuous distribution with two main reproductive areas: one in the contiguous provinces of Almeria and Murcia, and the other in Huelva province. Both populations are thought to maintain reproductive isolation. However, we present new records obtained from two areas (the provinces of Malaga and Cadiz) which are outside their previously known range. Malaga province and Cadiz province are located between the two traditional reproductive areas. The new records were based on 16 interviews with shepherds as well as information provided by three naturalists. The aim of this work was to analyze the spatial distribution of areas favourable to the spur-thighed tortoise in the southern Iberian Peninsula, using different models with the same group of variables but with a different number of records: known records, new records and a combination of them. We obtained a distribution model for the species in Andalusia consistent with all observations, which was related to climatic stability, climatic disturbances, and spatial situation. This model presented three main favourable areas: two are coincident with the two known nuclei, and the other is situated in the southern part of the region, in the contiguous provinces of Cadiz and Malaga. We conclude that it is important to consider all the observations in the distribution models because records outside the traditional reproductive areas can include other environmental characteristics appropriate for the species.  相似文献   

18.
Aedes mariae, Aedes phoeniciae and Aedes zammitii are three sibling species of the Mariae complex with a limited distribution. All these three species use semi-saline/saline rock pool habitats on the coastal areas of Mediterranean countries. The Eastern coast of the Mediterranean basin, including Turkey and Cyprus coasts, is a unique distribution area for Ae. phoeniciae. This study was designed to identify three sibling species of the Mariae complex based on molecular markers and also to determine the distribution pattern and genetic structure of the Ae. phoeniciae along the eastern Mediterranean basin. Larval and adult samples of Ae. zammitii and Ae. phoeniciae were collected from different rock pool habitats along the coastal regions of Turkey and Northern Cyprus. Species identifications were done primarily based on morphological identification key. Identifications were supported by using mitochondrial DNA cytochrome oxidase I (COI) and nuclear DNA Internal transcribed spacer 2 (ITS2) sequences. Population genetic analyses of Ae. phoeniciae were implemented based on NADH dehydrogenase 4 (ND4) sequence and 17 haplotypes were detected in the study area. Analyses of molecular variance (AMOVA) determined that the majority of the variation was within the populations (60.15 %) while variation between groups was 30.68 % and the variation within groups was 9.17 %, indicating low genetic structuring among groups.  相似文献   

19.
Faunistic records for 139 tachinid species from southwestern Turkey (Mu?la province and adjacent Ayd?n, Burdur, Denizli and Antalya provinces) are given. Another 17 species of the study area are known only from published records. The known fauna of Tachinidae of southwestern Turkey thus comprises 156 species. Zoogeographic analysis of the study area revealed that tachinids belong to 29 chorological categories, divided into two supergroups: 122 species (78.2%) are more eurybiontic, and also distributed in northern parts of the Palaearctic region (19 chorological categories belong here), whereas 34 species (21.8%) are distinctly thermophilic, and have a southern type of distribution (10 chorological categories are distinguished). Altogether, 52 species (33.3%) are recorded for the first time from Turkey.  相似文献   

20.
The mass emergence of floodwater mosquitoes, in particular Aedes sticticus and Aedes vexans, causes substantial nuisance and reduces life quality for inhabitants of infested areas and can have a negative impact on the socio‐economic conditions of a region. We compared the previous, present, and predicted geographic distribution of Ae. sticticus in Sweden. Previous records from the literature until 1990 list the species in three out of 21 Swedish counties. Beginning in 1998, studies show that the present distribution of the species covers 11 counties, with highest abundances in an east‐west belt in Central Sweden. Using climate data from the present and predicted climate scenarios, the expected distribution of Ae. sticticus in 2020, 2050, and 2080 could be modelled using GIS. As variables, mean temperatures and cumulative precipitation between May and August and degree slope were chosen. The predicted geographic distribution of Ae. sticticus will continue to increase and include 20 out of 21 Swedish counties. The expected temperature rise will increase the suitable area towards the northern part of Sweden by 2050. Some non‐suitable areas can be found along the south‐east coast due to insufficient amount of precipitation in 2050 and 2080. Modelling the expected distribution of a species using predicted climate change scenarios provides a valuable tool for risk assessments and early‐warning systems that is easily applied to different species and scenarios.  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