Bivalve distribution in hydrographic regions in South America: historical overview and conservation

Based on literature review and malacological collections, 168 native freshwater bivalve and five invasive species have been recorded for 52 hydrographic regions in South America. The higher species richness has been detected in the South Atlantic, Uruguay, Paraguay, and Amazon Brazilian hydrographic regions. Presence or absence data were analysed by Principal Coordinate for Phylogeny-Weighted. The lineage Veneroida was more representative in hydrographic regions that are poorer in species and located West of South America. The Mycetopodidae and Hyriidae lineages were predominant in regions that are richest in species toward the East of the continent. The distribution of invasive species Limnoperna fortunei is not related to species richness in different hydrographic regions there. The species richness and its distribution patterns are closely associated with the geological history of the continent. The hydrographic regions present distinct phylogenetic and species composition regardless of the level of richness. Therefore, not only should the richness be considered to be a criterion for prioritizing areas for conservation, but also the phylogenetic diversity of communities engaged in services and functional aspects relevant to ecosystem maintenance. A plan to the management of this fauna according to particular ecological characteristics and human uses of hydrographic regions is needed.     

Drosophila auraria复合种Period基因Thr-Gly区段的初步研究

测定了金色果蝇复合种（Drosophila auraria species complex）5个姐妹种（sibling species）和D.rufa的period(per)基因的Thr-Gly区段序列。该区段序列分析表明：DNA序列的碱其组成拥有果蝇其他基因的共同特点;颠换数多于转换数,两两种种间的颠换率与转换率的总比值为2～5,密码子第3位的颠换与转换的比值为2.5～5;同义替换/异义替换（Ks/Ka）值远大于10,且有的物种间根本不存在非同义突变,低的Ka值说明该复合种的per基因Thr-Gly区段在进化过程中可能承受着较强的选择压力。运用所得的核苷酸序列构建Drosophila auraria复合种的系统发育树,为澄清该类群的系统演化关系提供了新的线索。     

Phytogeographical evidence for post‐glacial dispersal limitation of European beech forest species

The post‐glacial migration of European beech Fagus sylvatica has been addressed by many studies using either genetic or fossil data or a combination of both. In contrast to this, only little is known about the migration history of beech forest understorey species. In a review of phytosociological literature, we identified 110 plant species which are closely associated with beech forest. We divided the distribution range of European beech forests into 40 geographical regions, and the presence or absence of each species was recorded for each region. We compared overall species numbers per region and numbers of narrow‐range species (species present in <10 regions). A multiple regression model was used to test for the explanatory value of three potential diversity controls: range in elevation, soil type diversity, and distance to the nearest potential refuge area. A hierarchical cluster analysis of the narrow‐range species was performed. The frequency of range sizes shows a U‐shaped distribution, with 42 species occurring in <10 regions. The highest number of beech forest species is found in the southern Alps and adjacent regions, and species numbers decrease with increasing distance from these regions. With only narrow‐range species taken into consideration, secondary maxima are found in Spain, the southern Apennines, the Carpathians, and Greece. Distance to the nearest potential refuge area is the strongest predictor of beech forest species richness, while altitudinal range and soil type diversity had little or no predictive value. The clusters of narrow‐range species are in good concordance with the glacial refuge areas of beech and other temperate tree species as estimated in recent studies. These findings support the hypothesis that the distribution of many beech forest species is limited by post‐glacial dispersal rather than by their environmental requirements.     

The geographical parallels of lithorheophil biotic community organisation of small streams of eastern Europe and northern Asia

The influence of geographical position on taxonomical composition and structure of communities inhabited stony riffles is considered on a material from 79 small streams situated in four regions of Eastern Europe (Moscow region, Southern Ural, Northern Caucasus and Mountain Crimea), as well as on publishing data on Asia and Northern Ural regions. Litoreophil communities of mentioned regions include different but closely allied species with similar habits. Eight basic living forms of litoreophils are common practically everywhere irrespective of geographical position and taxonomical composition of the community. The average number of species in a sample is also constant and includes 13-14 species. Local relief and climate influence the abundance of living forms and species diversity.     

Intraspecific sequence variation of chloroplast DNA among the component species of evergreen broad-leaved forests in Japan

For the purpose of phylogeographic study of lucidophyllous (evergreen broad-leaved) forests in Japan, we surveyed intraspecific chloroplast DNA (cpDNA) variation in 41 component species of such forests. Intraspecific cpDNA variations were detected in 14 species. In 15 species and one species group, 16 non-coding cpDNA regions were examined to find intraspecific sequence variation. The extent of variation in these regions was compared. The largest amount of intraspecific variation was detected in the rps16 region. A relatively large amount of intraspecific variation was detected in the petD-rpoA, rpl16, and trnL-F regions. It is suggested that these regions of cpDNA would be useful for detecting intraspecific variation in plant species, and could provide valuable information for various research purposes.     

Geographical and typological changes in fish guilds of South African estuaries

A comparative analysis of fish estuary association guilds was undertaken on some 190 South African estuaries. This pioneering study spanned three zoogeographic regions and included three broad estuarine types. The guild compositions of the estuaries were compared based on an importance value, incorporating taxonomic composition, numerical abundance and relative biomass. Multivariate analyses included both inter‐regional (zoogeographic) and intra‐regional (estuarine typology) comparisons. The major estuary‐associated guilds (estuarine species and marine migrant species) were important in all estuary types within all biogeographic regions. Significant differences both between regions and between estuary types within regions, however, were recorded. Cool–temperate estuaries were generally dominated by migratory species (estuarine migrants and marine migrant opportunists) while the importance of species dependent on estuaries (estuarine residents and estuarine‐dependent marine migrants) was higher in warm–temperate and subtropical regions. The significance of estuarine nursery areas, particularly in regions where estuaries are few in number, is highlighted. In terms of typology, migratory species assumed a greater importance in predominantly open systems, while freshwater and estuarine‐resident species were more important in predominantly closed systems. Predominantly closed estuaries, however, were also important for marine migrant species, which further highlights the significance of these systems as nursery areas for fishes.     

Character variation in separate body regions of Gerreidae (Osteichthyes: Teleostei) fishes inferred from geometric morphometrics

Body morphology is a valuable feature for distinguishing teleostean fishes. However, the utility of character variation in separate body regions has yet to be tested. The taxonomy of the Gerreidae family is controversial due to character overlapping among its fish species. This work aims to analyze and compare the body shape variation in three regions, cephalic, trunk, and caudal peduncle, using landmark data and geometric morphometric methods in 17 species and five genera of the family Gerreidae. The pattern of shape variation for the cephalic region consisted of well-defined character states exclusive of each species analyzed. Shape variation in the trunk and caudal peduncle regions does not distinguish all species in this study. This study showed that the dorsal cephalic profile is highly variable among the species, therefore, shape variation in this region is useful for distinguishing Gerreidae species. In contrast, some species within the same genus share similar shape states in the trunk and caudal peduncle regions, with the most shape variation in the dorsal profile and anal fin for the trunk and in the middle of the caudal peduncle.     

Species richness of resident and transient coral-dwelling fish responds differentially to regional diversity

Aim To determine whether the diversity of resident and transient coral‐dwelling fish responds differentially to gradients in regional species richness. Location Three regions in the Indo‐Pacific (Red Sea, western Indian Ocean, Great Barrier Reef) which contain increasingly larger regional diversities of reef fish. Methods I surveyed fish residing within branching coral species. Fish species were a priori categorized as resident or transient based on the degree of affiliation between the fish and live coral. To compare among regions that differ in coral diversity I used a modified species–volume relationship (SVR). Each point in the SVR represents the total number of fish species, resident or transient, found within the cumulative volume of a specific coral species. Empirical SVRs were further compared with random‐placement null models. Results For transient species, I found that the observed SVRs did not differ consistently from those expected from random samples drawn from the corresponding regional species pools. In addition, for a given volume of coral, more fish species were found in richer regions, indicating strong regional influences on local diversity. In contrast, resident richness was lower than that expected from random samples of the species pool, and richness in rich regions was reduced comparably more than in poor regions. The SVRs of resident species were similar among regions with different regional diversities. Main conclusion These results suggest that, within coral species, transient fish richness is mostly influenced by stochastic allocation of species from the regional pool. Conversely, richness of resident species within a coral species is limited, making it independent of regional diversity. Since higher regional diversity of resident fish was not accompanied by higher richness per coral species or by decreased niche breadth, higher regional diversity of resident fish species must be rooted in higher coral richness. Consequently, ecological interactions between functional groups (coral and fish) can be powerful drivers of regional biodiversity.     

大、小兴安岭植物区及交错区物种多样性比较研究

在中国东北大兴安岭植物区、小兴安岭植物区及交错区,选择典型群落,采用物种丰富度指数、Simpson指数、Shannon-Wiener指数及均匀度指数,研究了大兴安岭植物区、小兴安岭植物区及交错区物种构成和不同分布区群落的结构。分析比较了3个植物区物种多样性指数及不同生活型物种多样性指数及均匀度指数,结果表明：大、小兴安岭植物区与交错区植物种类过渡性明显,小兴安岭植物区和交错区植物群落结构以落叶松、红松、白桦针阔混交林为主,大兴安岭植物区以兴安落叶松、东北白桦、樟子松为主;大、小兴安岭植物区及交错区物种多样性指数表现为小兴安岭植物区＞交错区＞大兴安岭植物区;大、小兴安岭植物区及交错区不同生活型物种多样性指数变化为草本层＞灌木层＞乔木层,乔木层物种多样性指数差异显著,灌木层和草本层差异不显著。     

Biogeography of freshwater fishes of the Balkan Peninsula

Delineating biogeographical regions is a critical step towards the establishment and evaluation of conservation priorities. In the present study, we analysed the distribution patterns of the freshwater fish of an understudied European biodiversity hotspot, the Balkan Peninsula. Based on the most extensive available database of native freshwater fish species distributions, we performed a hierarchical clustering analysis to identify the major biogeographical regions of the Balkan Peninsula. We also highlighted the ‘hottest hotspots’ of freshwater fish diversity across the delimited biogeographical regions by describing the patterns of species richness, endemic and vulnerable species; indicator species were also determined. The bioregionalisation scheme consisted of eight groups of drainage basins that correspond to distinct regions of the Balkan Peninsula. Overall, the delineated biogeographical regions varied in terms of species richness, endemism, vulnerability (i.e. extinction threats) and indicator species composition. From a conservation perspective, this study emphasises the prioritisation of areas characterised by high levels of irreplaceability (endemism) and vulnerability (i.e. the Attikobeotia region, Ionian Sea and Prespa Lakes) and stresses the necessity of implementing a network of protected freshwater areas across the Balkan Peninsula.     

退田还湖对洞庭湖湿地鸟类的影响

对洞庭湖湿地退田还湖前后湿地鸟类群落结构进行对比分析,阐述了湿地鸟类群落结构的变化趋势.洞庭湖湿地鸟类群落结构的变化表明,鸟类的数量在退田还湖后明显上升,与1992年洞庭湖湿地鸟类名录相比增加2目16科174种,尤其是雁鸭类、鹬鹆类、隼类和鸣禽的种数增加迅速.优势种退田还湖前只有32种,退田还湖后增加到74种.不同的湖区因生态环境异质性,退田还湖前后鸟类的群落结构也有差异.在记录的312种鸟类中,其中东洞庭湖分布有297种,南洞庭湖164种,西洞庭湖217种,共有鸟类138种,东洞庭湖特有鸟类较多(48种).经调查,退田还湖(垸)区鸟类群落结构变化更为明显,青山垸分布13目33科77种,西畔山洲垸分布8目20科37种,两垸共有鸟种33种,青山垸特有鸟类有41种,西畔山洲垸5种.     

Biogeographic distribution of the Phytoseiidae (Acari: Mesostigmata)

More than 1982 species in 90 genera were included in an analysis of the biogeography of the Phytoseiidae, a family of predatory mites. Seven biogeographic regions were taken into account: Nearctic, Neotropical, Ethiopian, West Palaearctic, East Palaearctic, Oriental, and Australasian. The number of species was particularly high in the Neotropical, Oriental, and West Palaearctic regions. These regions also present the highest levels of species endemism. The number of genera was quite similar in all regions except for the Neotropics, which also had a high level of endemism. The possible Gondwanian (Neotropical, Ethiopian, Australasian, and Oriental regions) origin of the Phytoseiidae, most probably in the Neotropics, and their possible radiation to Laurasia (Nearctic, West Palaearctic, and East Palaearctic regions) are discussed. The comparison between genera and species in the different biogeographic regions indicate the importance of both dispersal and vicariance events in the evolution of the group. Dispersal is assumed to have been most important between Neotropical and Nearctic regions and between East Palaearctic and Oriental regions, whereas vicariance could have been the dominating process between Australasian, Ethiopian, and Oriental regions, as well as between West and East Palaearctic regions. A parsimony analysis of endemicity showed the Neotropical and the Nearctic regions to be isolated from the other regions. This is certainly due to a diversification after the continents drifted apart and then a high dispersal between Nearctic and Neotropical regions. Different phylogenetic hypotheses and scenarios are proposed for each subfamily based on the results obtained and further investigations are proposed.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 845–856.     

Microcrustacean communities in streams from two physiographically contrasting regions of Britain

ABSTRACT. Benthic microcrustaceans were sampled from forty-three streams in two physiographically contrasting regions of Britain: lowland southern England and upland Wales. Lowland streams had a significantly higher species richness than upland streams and, of the forty-three copepod and cladoceran species identified, only fourteen (33%) were found in both the lowlands and uplands. Canonical correspondence analysis revealed large differences in community structure between regions and between streams within regions. Differences within regions were related to pH, the distance downstream of a site and the presence of upstream impoundments. Variables underlying the large biological differences between regions are also discussed, including differences in chemistry (ionic content), physical parameters (e.g. flow), habitat availability and the influence of species biogeography. The importance of understanding species ecology and biogeography when assessing pollution impacts on stream communities is emphasized and a model is proposed for predicting the composition of microcrustacean communities in temperate European streams.     

Global diversity of water mites (Acari,Hydrachnidia; Arachnida) in freshwater

The Hydrachnidia (water mites) represent the most important group of the Arachnida in fresh water. Over 6,000 species have been described worldwide, representing 57 families, 81 subfamilies and more than 400 genera. The article analyzes extant water mite diversity and biogeography. Data on distribution and species richness of water mites are substantial but still far from complete. Many parts of the world are poorly investigated, Oriental and Afrotropical regions in particular. Moreover, information among different freshwater habitats is unbalanced with springs and interstitial waters disproportionately unrepresented. Therefore, more than 10,000 species could be reasonably expected to occur in inland waters worldwide. Based on available information, the Palaearctic region represents one of the better investigated areas with the highest number of species recorded (1,642 species). More than 1,000 species have been recorded in each of the Neotropical (1,305 species) and Nearctic regions (1,025 species). Known species richness is lower in Afrotropical (787 species) and Australasian (694 species) regions, and lowest in the Oriental region (554 species). The total number of genera is not correlated with species richness and is distinctly higher in the Neotropical (164 genera); genus richness is similar in the Palaearctic, Nearctic and Australasian regions (128–131 genera) and is lower in the Afrotropical and Oriental regions with 110 and 94 genera, respectively. A mean number of about three genera per family occur in the Palaeartic, Nearctic and Oriental while an average of more than four genera characterizes the families of Australasian and Afrotropical regions and more than five genera those of the Neotropical. Australasian fauna is also characterized by the highest percentage of endemic genera (62%), followed by Neotropical (50.6%) and Afrotropical (47.2%) regions. Lower values are recorded for the Palaearctic (26.9%), Oriental (24.4%) and Nearctic (21.4%). The Palaearctic and Nearctic have the highest faunistic similarity, some minor affinities are also evident for the generic diversification of Holarctic and Oriental families. The faunas of Southern Hemisphere bioregions are more distinct and characterized by the presence of ancient Gondwanan clades with a regional diversification particularly evident in the Neotropics and Australasia. This scenario of water mite diversity and distribution reflect the basic vicariance pattern, isolation, phylogenetic diversification, recent climatic vicissitudes and episodes of dispersal between adjacent land masses together with extant ecological factors can be evoked to explain distribution patterns at a global scale. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

中国38个地区兰科植物区系成分的比较分析

通过对中国38个地区共147属,984种兰科植物的区系成分的统计,分析了各地区兰科植物的属种热带成分/温带成分(R/T)值随纬度的变化趋势;并利用SPSS 20.0软件对各地区兰科植物的区系成分进行聚类分析。结果表明:(1)38个地区147属兰科植物可划分为11种分布区类型和9种变型,984种兰科植物可划分为12种分布区类型和6种变型。(2)属级水平上R/T值随纬度的升高总体呈下降趋势,38个地区中23个地区为热带性质,13个地区为温带性质,峨眉山和金佛山的热带性质和温带性质相等;种级水平上除俄贤岭的特殊岛屿石灰岩环境造成极强的热带性质外,其他地区的R/T值随纬度的升高而降低,表现出明显的纬向地带性特点。(3)38个地区兰科植物属种级区系类型存在分异现象,即147属兰科植物以热带亚洲分布(24.71%)、北温带分布(19.14%)和热带亚洲至热带大洋洲分布(15.32%)为主,而984种兰科植物除热带亚洲分布(30.28%)外,则以中国特有分布(26.89%)和中国-日本分布(12.85%)为主。(4)属种级聚类结果显示,种级水平的聚类分析比属级水平的聚类更能体现出纬度相近其区系成分也相近的特点。     

Floristic Geography of Piper (Piperaceae) in China

Piper is the largest genus and important Pantropical components of the Piperaceae family with approximately 1000-2000 species in the world. China is in the northern verge of its natural distribution. In this study, floristic geography of the Piper genus in China was analyzed to reveal its botanical characteristic, origins of speciation and its dispersal channels. The study results showed Yunnan province is one of the very important distribution regions for Piper species, served as the center of the Piper species dispersal toward to the eastern and northern regions of China with gradually reduced species numbers. The similarity level appeared to be low for its species among different provinces, and the Piper distribution regions could be approximately clustered into three clades: tropical clade, subtropical clade and Taiwan clade. Cladistically, Piper species found in China have the highest proportions which were endemic to China, and then followed by Piper species distributed in Tropical Asia, only few species belonged to Pantropical and East Asia areal types. The floristic geography of Piper genus in China is related to that of Indo Chinese Peninsula, Java Islands and Indian Peninsula in some degrees, but not closely related. This study revealed Yunnan province is one of the central of origins for the Piper species, and or one of the central of regions for its species diversification, and the Piper species of Taiwan mainly came from Philippine islands and further diversified into Taiwan clade. Our study results presented a useful method for the systematic studying of Piper genus taxonomy and the evolution of Piper speciation.     

The biogeography of naturalization in alien plants

Aim  This paper reviews the main geographical determinants of naturalization in plants.
Location  Global.
Methods  Comparative studies of large data sets of alien floras are the main source of information on global patterns of naturalization.
Results  Temperate mainland regions are more invaded than tropical mainland regions but there seems to be no difference in invasibility of temperate and tropical islands. Islands are more invaded than the mainland. The number of naturalized species in temperate regions decreases with latitude and their geographical ranges increase with latitude. The number of naturalized species on islands increases with temperature. Naturalized species contribute to floristic homogenization, but the phenomenon is scale-dependent.
Main conclusions  Some robust patterns are evident from currently available data, but further research is needed on several aspects to advance our understanding of the biogeography of naturalization of alien plants. For example, measures of propagule pressure are needed to determine the invasibility of communities/ecosystems/regions. The patterns discussed in this paper are derived largely from numbers and proportions of naturalized species, and little is known about the proportion of introduced species that become naturalized. Further insights on naturalization rates, i.e. the proportion of aliens that successfully naturalize within regions, and on geographical and other determinants of its variation would provide us with better understanding of the invasion process. Comparative studies, and resulting generalizations, are almost exclusively based on numbers of species, but alien species differ in their impact on native biodiversity and ecosystem processes.