Structure of parasitic arthropod communities in forest small mammals

Species composition and structure of ectoparasite arthropod communities were examined all year round six years in the bank vole Clethrionomys glareolus, Ural wood mouse Apodemus uralensis and the common shrew Sorex araneus in forests of the Ilmen'-Volkhov depression. In total, 4500 host samples have been examined and all ectoparasites have been collected. The species composition of ectoparasite community in small mammal species are as follows: the bank vole--29 insect, tick and mite species, the common shrew--23 species, the Ural wood mouse--16 species. In forest biotopes, many temporary ectoparasitic species occur on several host species living in the same habitats under a forest canopy and contacting each other. A parasitic supracommunity in the ecosystem examined has a pool of temporary ectoparasites, which is available for all the community of small mammals. A role of different rodent and shrew species are hosts of insects and ticks changes depending on a density of potential host populations and numerous other environment factors.     

Analysis of life forms of rheophilic macrobenthos: a new approach to community classification

The taxonomical composition and number of life forms of macrobenthos assemblages were described for 82 streams in the Central Part of European Russia. The data (445 qualitative samples) were taken from the bottom and macrophytes. The communities typical for four main types of substratum (stones, macrophytes, sand and mud) differ at the level of species, genera, families and life forms. Communities from other habitats were either similar to the main types or demonstrated intermediate characteristics. The list of life forms or families provides more reliable information than that of species because the latter strongly depends on geographic location of a particular site. The author describes life forms and families that can characterize main types of macrobenthics communities connected with different substrata.     

成都地区居室庭院蚂蚁区系及群落相似性分析

对成都地区居室庭院环境中的蚂蚁种类进行了调查,发现成都地区居室庭院蚂蚁种类有26种,隶属于3个亚科,12属。按地理和气候环境将成都地区蚂蚁区系划分为4个动物地理区域,对其种类组成、分布和区系特点进行了分析和讨论,根据群落相似性系数的比较,讨论了成都地区居室庭院蚂蚁群落的稳定性。     

Sesto Contributo Alla Conoscenza Dell' “ Artemisia Verlotorum „ Lamotte (Con 4 Figg. Nel Testo)

Abstract

This study compared the richness of saproxylic beetle species and the composition of species assemblages between the major forests types of the south‐east of France. The forests differed by their geographical position and their composition in tree species. The results confirmed the existence of a clear local identity of the saproxylic beetles communities. This identity combined three geographical and ecological factors: the geographical position, the altitude and the dominant species of trees. Surprisingly, the period length since the last important perturbation of the stand was not a determinant factor to explain the composition of the saproxylic communities. Selective logging and deadwood retention favoured the increase of the diversity of saproxylic species. This diversity reached a maximum during the first 10 years following the perturbation, was the lowest 30 years after the stand perturbation, but increased again after 50 years with a different species composition.     

Biogeographical patterns of rocky intertidal communities along the Pacific coast of North America

Aim Our aim in this paper is to present the first broad‐scale quantification of species abundance for rocky intertidal communities along the Pacific coast of North America. Here we examine the community‐level marine biogeographical patterns in the context of formerly described biogeographical regions, and we evaluate the combined effects of geographical distance and environmental conditions on patterns of species similarity across this region. Location Pacific coast of North America. Methods Data on the percentage cover of benthic marine organisms were collected at 67 rocky intertidal sites from south‐eastern Alaska, USA, to central Baja California Sur, Mexico. Cluster analysis and non‐metric multidimensional scaling were used to evaluate the spatial patterns of species similarity among sites relative to those of previously defined biogeographical regions. Matrices of similarity in species composition among all sites were computed and analysed with respect to geographical distance and long‐term mean sea surface temperature (SST) as a measure of environmental conditions. Results We found a high degree of spatial structure in the similarity of intertidal communities along the coast. Cluster analysis identified 13 major community structure ‘groups’. Although breaks between clusters of sites generally occurred at major biogeographical boundaries, some of the larger biogeographical regions contained several clusters of sites that did not group according to spatial position or identifiable coastal features. Additionally, there were several outliers – sites that grouped alone or with sites outside their region – for which localized features may play an important role in driving community structure. Patterns of species similarity at the large scale were highly correlated with geographical distance among sites and with SST. Importantly, we found community similarity to be highly correlated with long‐term mean SST while controlling for the effects of geographical distance. Main conclusions These findings reveal a high degree of spatial structure in the similarity of rocky intertidal communities of the north‐east Pacific, and are generally consistent with those of previously described biogeographical regions, with some notable differences. Breaks in similarity among clusters are generally coincident with known biogeographical and oceanographic discontinuities. The strong correlations between species similarity and both geographical position and SST suggest that both geography and oceanographic conditions have a large influence on patterns of intertidal community structure along the Pacific coast of North America.     

Geographical ecology of dry forest tree communities in the West Indies

Aim

Seasonally dry tropical forest (SDTF) of the Caribbean Islands (primarily West Indies) is floristically distinct from Neotropical SDTF in Central and South America. We evaluate whether tree species composition was associated with climatic gradients or geographical distance. Turnover (dissimilarity) in species composition of different islands or among more distant sites would suggest communities structured by speciation and dispersal limitations. A nested pattern would be consistent with a steep resource gradient. Correlation of species composition with climatic variation would suggest communities structured by broad‐scale environmental filtering.

Location

The West Indies (The Bahamas, Cuba, Hispaniola, Jamaica, Puerto Rico, US Virgin Islands, Guadeloupe, Martinique, St. Lucia), Providencia (Colombia), south Florida (USA) and Florida Keys (USA).

Taxon

Seed plants—woody taxa (primarily trees).

Methods

We compiled 572 plots from 23 surveys conducted between 1969 and 2016. Hierarchical clustering of species in plots, and indicator species analysis for the resulting groups of sites, identified geographical patterns of turnover in species composition. Nonparametric analysis of variance, applied to principal components of bioclimatic variables, determined the degree of covariation in climate with location. Nestedness versus turnover in species composition was evaluated using beta diversity partitioning. Generalized dissimilarity modelling partitioned the effect of climate versus geographical distance on species composition.

Results

Despite a set of commonly occurring species, SDTF tree community composition was distinct among islands and was characterized by spatial turnover on climatic gradients that covaried with geographical gradients. Greater Antillean islands were characterized by endemic indicator species. Northern subtropical areas supported distinct, rather than nested, SDTF communities in spite of low levels of endemism.

Main conclusions

The SDTF species composition was correlated with climatic variation. SDTF on large Greater Antillean islands (Hispaniola, Jamaica and Cuba) was characterized by endemic species, consistent with their geological history and the biogeography of plant lineages. These results suggest that both environmental filtering and speciation shape Caribbean SDTF tree communities.     

The roles of environment and space in shaping stream diatom communities

Diatoms are widely used in stream quality assessment due to their response to the local environment. Diatoms are also influenced by many large-scale processes and so the diatom communities of boreal streams incorporate a strong spatial component at a regional level. What is not properly known yet is whether the variation in diatom communities between regions is larger than the variation in measured environmental variables. We studied the roles of environment and space in accounting for variability in stream diatom communities across four regions in Finland. According to canonical correspondence analysis, geographical coordinates, nutrient concentrations (total N and P), and water conductivity were the most important factors affecting variation in diatom community composition. Of physical factors, depth and current velocity were also significant. According to Mantel tests, both environmental and geographical distances were related to dissimilarity in diatom community composition. Analysis of Similarities indicated that the regional differences in diatom community composition were larger than the regional differences in environmental variables. We also found many indicator species confined to certain regions. Our results suggest that the four study regions differ in their diatom species composition more than in their environmental features and that diatoms are structured not only by the local environment but also by large-scale processes, possibly related to history, climate and dispersal. These results imply that, while diatom species composition reflects well the environmental differences between regions, future bioassessments would benefit from regional stratification. Otherwise, relationships with environmental variables may be masked by trans-regional differences in species pools caused by the large-scale processes.     

Floristics of forests across low nutrient soils in Sulawesi,Indonesia

The island of Sulawesi formed from the joining of proto-islands roughly three million years ago. Regions of zoological endemism, corresponding to the proto-islands, have been reported. Sulawesi's tree communities, however, remain poorly documented. In better-studied tropical regions, soil types similar to those found in Sulawesi often have distinctive tree communities. To gather data on Sulawesi's tree communities, we established ten (0.25 ha) plots on four soil types across three regions. We documented diversity, endemism, dominance, and species composition. Linear models of species composition showed greater influence of geographic distance rather than soil, and no relationship with climate. This suggests that the legacy of Sulawesi's formation may have influenced tree communities more so than the soil types we sampled. Most of our plots were on stressful soil types making it difficult to conclude on the importance of edaphic specialization in the Sulawesi tree flora. The lack of climatic effects reflects Sulawesi's position within the wet tropics where the small climatic differences are unlikely to have large influence on tree communities.     

Heterotrophic flagellate biodiversity and community structure in freshwater streams

The species diversity and community structure of heterotrophic flagellates in watercourses from different geographical regions were investigated. Forty-one species have been identified. The species diversity of cercomonads, kinetoplastids, choanoflagellates, and flagellates is the highest. Bodo saltans, B. designis and Goniomonas truncata are the most common species. Planktonic communities in different streams are most similar in terms of species composition. The highest similarity within benthic cenoses was noted between geographically distant communities. Communities of heterotrophic flagellates seem to be highly heterogenous systems; species distribution depends mainly on the type of habitat and not on geographical factors.     

Environment drives high phylogenetic turnover among oceanic bacterial communities

Although environmental filtering has been observed to influence the biodiversity patterns of marine bacterial communities, it was restricted to the regional scale and to the species level, leaving the main drivers unknown at large biogeographic scales and higher taxonomic levels. Bacterial communities with different species compositions may nevertheless share phylogenetic lineages, and phylogenetic turnover (PT) among those communities may be surprisingly low along any biogeographic or environmental gradient. Here, we investigated the relative influence of environmental filtering and geographical distance on the PT between marine bacterial communities living more than 8000 km apart in contrasted abiotic conditions. PT was high between communities and was more structured by local environmental factors than by geographical distance, suggesting the predominance of a lineage filtering process. Strong phenotype-environment mismatches observed in the ocean may surpass high connectivity between marine microbial communities.     

论古尔班通古特沙漠植物多样性的一般特点

古尔斑通古特沙漠处于中亚荒漠与内亚（亚洲中部）荒漠之间的过渡,其气候虽以干旱少雨、蒸发强烈、多风、日照强、温度变化剧烈的大陆性荒漠气候为特点,但由于降水季节分配较均匀,冬春有一定雨雪,植被相对较为茂密,以固定和半固定沙漠为主,共采集记录到２０８种高等植物,１８个植物群落类型,ｌｌ类植物生活型。植物多样性还包括下列一般特点：区系地理成分多样,但中亚成分占优势;有少量古老种,特有现象微弱,黎科植物占明显优势;早生植物为主;长营养期１年生植物有一定比例;短命和类短命植物获得发育等。由于近几十年来的过牧（牲畜的“冬窝子”）和滥采滥挖燃料及有经济价值的植物,植物多样性受破坏严重。当前的紧迫任务是加强保护,对有些物种还须采取措施,进行抢救。     

Patterns of phylogenetic beta diversity in China's grasslands in relation to geographical and environmental distance

Patterns and determinants of beta (β-) diversity can be used to explore the underlying mechanisms regulating community assembly. Despite being the most commonly used measure of β-diversity, species turnover does not consider the evolutionary differences among species, treating all species equally. Incorporating information on phylogenetic non-independence or relatedness among species in the calculation of β-diversity may substantially advance our understanding of the ecological and evolutionary mechanisms structuring communities. Here, we investigate the relative influence of geographical distance and differences in environmental conditions (environmental distance) on the phylogenetic β-diversity between grassland communities expanding 4000 km across the Tibetan Plateau, the Inner Mongolia Plateau and the Xinjiang Autonomous Region in China. Both observed and standardized effect size of phylogenetic β-diversity were significantly correlated with geographical and environmental distance across all regions. However, the effect of geographical distance on the standardized effect size of phylogenetic β-diversity disappeared when environmental distance was controlled. We also found that within different regions, the effect of environmental distance on both observed and standardized effect size of phylogenetic β-diversity was more significant than geographical distance. Among environmental variables, climate played a more important role in shaping observed phylogenetic β-diversity across and within regions, and standardized effect size of phylogenetic β-diversity across regions. Soil properties played a more important role in shaping standardized effect size of phylogenetic β-diversity within regions. The phylogenetic β-diversity of species from dicot and monocot clades exhibited similar patterns along environmental and geographical distance. The results suggest that at the study scale, phylogeny of grassland communities in China is predominantly structured by environmental filtering, and the dominant environmental factors may be scale-dependent.     

Environmental heterogeneity influences life-form richness and species composition but not species richness of aquatic macrophytes in tropical coastal rivers

1. The coastal rivers of the São Paulo State in SE Brazil have different lengths and seawater influence. We evaluated whether: (1) environmental heterogeneity (EH) is associated with the species and life-form richness of aquatic macrophytes; and (2) EH and geographical distance influence species composition in these coastal rivers.
2. We recorded the macrophyte species and life form occurrence and collected explanatory variables characterising the water, sediment, and river channel at 100 sampling sites over 8 rivers. We applied a principal component analysis to the explanatory variables and calculated the rivers' EH using the range of principal component 1 scores. We also determined the position of each river mouth along the coastline to measure the distance between the rivers. We used quasi-Poisson generalised linear models to evaluate the effects of EH on richness of species and life forms. To determine the effect of EH and geographical distance (Euclidean distance matrices) on the variation in species composition (Jaccard dissimilarity matrix) among the rivers, we applied multiple regressions on distance matrices.
3. The most heterogeneous river had heterogeneity score about five times greater than the least heterogeneous river. Sediment salinity, river width, total phosphorus concentration of water and distance from river mouth were the most important variables contributing to the rivers' EH. We found that EH did not explain variation in species richness; however, it had a significant positive relationship with life-form richness. The effect of EH was greater than that of the geographical distance on the variation in species composition among the rivers. The pairs of rivers with the most similar EH were the most similar in species composition, but not all of them were geographically close.
4. We conclude that EH influences life-form richness but does not influence species richness of aquatic macrophytes in the coastal rivers we studied; however, EH does influence species composition regardless of geographical distance among rivers.

     

江苏分布的中国种子植物特有属研究

经调查和统计,江苏分布的中国种子植物特有属有18属,含19种,隶属于17个科,科、属、种分别占中国种子植物特有属总数的19.32%、5.61%和2.53%。根据自然地理特征将江苏分为6个地区：黄淮平原、江淮平原、滨海平原、长江三角洲、北部低山丘陵和西南低山丘陵。首次采用特有性指数(EI)研究上述地区的特有属分布,结果发现：EI值最高的是西南低山丘陵（4.83）,其次是长江三角洲（3.89）,黄淮平原和滨海平原的特有性指数最低（1.67）。因此该区的特有属植物的种类组成较贫乏,地理分布不均,并具有生活型多样,古特有属比例较高等特征。     

Trends in the Discovery of New Marine Natural Products from Invertebrates over the Last Two Decades – Where and What Are We Bioprospecting?

It is acknowledged that marine invertebrates produce bioactive natural products that may be useful for developing new drugs. By exploring untapped geographical sources and/or novel groups of organisms one can maximize the search for new marine drugs to treat human diseases. The goal of this paper is to analyse the trends associated with the discovery of new marine natural products from invertebrates (NMNPI) over the last two decades. The analysis considers different taxonomical levels and geographical approaches of bioprospected species. Additionally, this research is also directed to provide new insights into less bioprospected taxa and world regions. In order to gather the information available on NMNPI, the yearly-published reviews of Marine Natural Products covering 1990-2009 were surveyed. Information on source organisms, specifically taxonomical information and collection sites, was assembled together with additional geographical information collected from the articles originally describing the new natural product. Almost 10000 NMNPI were discovered since 1990, with a pronounced increase between decades. Porifera and Cnidaria were the two dominant sources of NMNPI worldwide. The exception was polar regions where Echinodermata dominated. The majority of species that yielded the new natural products belong to only one class of each Porifera and Cnidaria phyla (Demospongiae and Anthozoa, respectively). Increased bioprospecting efforts were observed in the Pacific Ocean, particularly in Asian countries that are associated with the Japan Biodiversity Hotspot and the Kuroshio Current. Although results show comparably less NMNPI from polar regions, the number of new natural products per species is similar to that recorded for other regions. The present study provides information to future bioprospecting efforts addressing previously unexplored taxonomic groups and/or regions. We also highlight how marine invertebrates, which in some cases have no commercial value, may become highly valuable in the ongoing search for new drugs from the sea.     

Deconstructing spatial patterns in species composition of ectoparasite communities: the relative contribution of host composition,environmental variables and geography

Aim We determined whether dissimilarity in species composition between parasite communities depends on geographic distance, environmental dissimilarity or host faunal dissimilarity, for different subsets of parasite species with different levels of host specificity. Location Communities of fleas parasitic on small mammals from 28 different regions of the Palaearctic. Method Dissimilarities in both parasite and host species composition were computed between each pair of regions using the Bray–Curtis index. Geographic distances between regions were also calculated, as were measures of environmental dissimilarity consisting of the pairwise Euclidean distances between regions derived from elevation, vegetation and climatic variables. The 136 flea species included in the dataset were divided into highly host‐specific species (using 1–2 host species per region, on average), moderately host‐specific species (2.2–4 hosts per region) and generalist species (>4 hosts per region). The relative influence of geographic distance, host faunal dissimilarity and environmental dissimilarity on dissimilarity of flea species composition among all regions was analysed for the entire set of flea species as well as for the three above subsets using multiple regressions on distance matrices. Results When including all flea species, dissimilarity in flea species composition was affected by all three independent variables, although the pure effect of dissimilarity in host species composition was the strongest. Results were different when the subsets of fleas differing in host specificity were treated separately. In particular, dissimilarity in species composition of highly host‐specific fleas increased solely with environmental dissimilarity, whereas dissimilarity for both moderately specific and non‐specific fleas increased with both geographic distance and dissimilarity in host species composition. Main conclusions Host specificity seems to dictate which of the three factors considered is most likely to affect the dissimilarity between flea communities. Counter‐intuitively, environmental dissimilarity played a key role in determining dissimilarity in species composition of highly host‐specific fleas, possibly because, although their presence in a region relies on the occurrence of particular host species, their abundance is itself mostly determined by climatic conditions. Our results show that deconstructing communities into subsets of species with different traits can make it easier to uncover the mechanisms shaping geographic patterns of diversity.     

On the ecology of Thelypteris limbosperma — a synecological investigation of T. limbosperma-dominated stands in W Norway

The investigation is based on phytosociological and ecological analyses of T. limbosperma-dominated stands from different parts of W Norway. The distribution and floristical composition of the stands are related to different environmental parameters, such as climate, soil and topography. The data are analysed by numerical methods, of which two-way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. The broad-scale distribution of T. limbosperma stands is determined by climatic factors. Within its distribution area soil factors and human influence govern the floristic composition and development of different types of such stands. Based on the TWINSPAN classification 9 different stand types are distinguished.
The first major division of the TWINSPAN classification is mainly correlated with soil factors. Most of the stands growing on the richest soils are interpreted as representing regeneration stages after intensive human influence. Divisions at lower levels are well correlated with altitude and temperature conditions.
The stands are all characterized by low pH and base saturation. Some types are concentrated to certain geographical regions, indicating that both altitudinal and west-east-gradients are important in influencing the floristic composition of the different types. The investigations indicate that T. limbosperma has a rather narrow realised phytosociological niche. It is mainly concentrated to stands that are floristically most related to the poorest part of Vaccinio-Piceion communities. Occasionally it is also dominant in Alno-Padion and Lactucion alpinae communities.     

Influence of microclimate and species interactions on the composition of plant and invertebrate communities in alpine northern Norway

We assessed the effects of both biotic processes and abiotic factors on the community composition of vascular plant species and invertebrates at a site in northern Norway. Plant species were assigned to functional (woody versus herbaceous) and biogeographic (boreal versus alpine) groups. Invertebrate species were classified as either herbivore or predator. When species interactions and effects of the abiotic environment were partitioned, boreal species appeared to influence the distribution of alpine species and woody species the distribution of herbaceous species. Analysis of partial correlations indicated that facilitation was the dominant mode of interaction between the two pairs of plant groups. Among abiotic factors, the thermal environment probably influenced all components of the plant and invertebrate communities, except for predatory invertebrates, and wind appeared important in determining the composition of woody and alpine components of the plant community but not the herbaceous component. The composition of the boreal component of the plant community apparently influenced the composition of all invertebrate communities, except for predatory invertebrates. The composition of the woody component of the plant community influenced the composition of both herbivore and predator communities. The alpine plant-community composition influenced predatory invertebrate community composition. Woody plant community composition influenced the composition of both herbivore and predator communities. Our analytic approach, based on two kinds of structural equation models (d-separation and path analysis), provides a useful method for identifying the biotic as well as abiotic factors that influence community structure.     

Die Testaceen (Protozoa,Rhizopoda) einiger Hochgebirgsgewässer von Mexiko,Costa Rica und Guatemala

The present paper deals with the Testacea living in several Mexican and Central American high-mountain waters. A total of 127 species, varieties and forms including 11 new ones are detected. Faunistical, ecological, zoogeographical and taxonomical notes are given. The results of investigation are represented as diagrams and extensive illustrations are provided.