Number Of Common Species Research Articles

Latitudinal variation and driving factors of above-ground carbon proportion of large trees in old-growth forests across China

Large trees play a vital role in forest carbon stocks, dominating the distribution of community biomass. However, climate change and deforestation are reducing large trees globally, resulting in regional differences in their contribution to carbon stocks. Here, we examined the latitudinal change pattern and drivers of large trees' contributions to stand carbon stocks. Above-ground carbon storage was calculated for 530 plots in old-growth forests across China. Linear regression was used to calculate latitudinal variation in the proportion of above-ground carbon in large trees (i.e., AGC proportion). Variance partitioning and multiple linear regression were used to calculate the relative importance of species diversity, stand structure, functional traits, and environmental factors to AGC proportion. The study found that AGC proportion decreased with increasing latitude, averaging at 64.44 %. Stand structure, particularly the coefficient of variation of DBH, was identified as the key drivers of the AGC proportion. The number of common species (Hill's 1D) had no direct effect on the AGC proportion, while wood density, maximum tree height, and leaf nitrogen-to‑phosphorus ratio showed negative effects. The mass-ratio effects on AGC proportion were stronger than diversity effects. Climate variables primarily affected the AGC proportion through stand variables. These results indicate that simultaneously managing high diversity and AGC proportion may pose challenges. Moreover, considering the substantial contribution of large trees to carbon stocks, their storage capacity and sensitivity to environmental changes exert significant control over forest carbon cycles. Therefore, preserving and enhancing the carbon sink function of old-growth forests in the face of climate change and disturbance may depend primarily on protecting existing large trees and soon-to-be large-diameter trees.

A network-based approach to identifying correlations between phylogeny, morphological traits and occurrence of fish species in US river basins.

The complex network framework has been successfully used to model interactions between entities in Complex Systems in the Biological Sciences such as Proteomics, Genomics, Neuroscience, and Ecology. Networks of organisms at different spatial scales and in different ecosystems have provided insights into community assembly patterns and emergent properties of ecological systems. In the present work, we investigate two questions pertaining to fish species assembly rules in US river basins, a) if morphologically similar fish species also tend to be phylogenetically closer, and b) to what extent are co-occurring species that are phylogenetically close also morphologically similar? For the first question, we construct a network of Hydrologic Unit Code 8 (HUC8) regions as nodes with interaction strengths (edges) governed by the number of common species. For each of the modules of this network, which are found to be geographically separated, there is differential yet significant evidence that phylogenetic distance predicts morphological distance. For the second question, we construct and analyze nearest neighbor directed networks of species based on their morphological distances and phylogenetic distances. Through module detection on these networks and comparing the module-level mean phylogenetic distance and mean morphological distance with the number of basins of common occurrence of species in modules, we find that both phylogeny and morphology of species have significant roles in governing species co-occurrence, i.e. phylogenetically and morphologically distant species tend to co-exist more. In addition, between the two quantities (morphological distance and phylogentic distance), we find that morphological distance is a stronger determinant of species co-occurrences.

Soil Seed Bank Characteristics of Nitraria tangutorum Nebkhas in a Desert–Oasis Ecotone

Understanding soil seed banks (SSBs) of Nitrariatangutorum nebkhas is critical for vegetation restoration and ecological management in desert–oasis ecotones. In this study, we conducted a survey in the field and a seed germination experiment in the laboratory to investigate the characteristics of SSB in different sizes and parts of nebkhas and to examine their relationship with aboveground vegetation. The results showed that there were 17 species of plants in six families in the SSB of Nitraria tangutorum nebkhas in a desert–oasis ecotone, dominated by Chenopodiaceae. The life forms were mainly annual herbs, accounting for 58.82%–71.43%. The number of species in the SSB were in the order of large nebkha > medium nebkha > small nebkha, and there was no significant difference in SSB density. However, SSB densities in different parts of each nebkha were in the order bottom > middle > top. The densities were significantly different and showed a decreasing trend as soil depth increased. Most of the plant seeds were distributed in the 0–5 cm soil layer. The similarity coefficient between the SSB of each nebkha and the aboveground vegetation was high. From the bottom to the top, the number of common species and similarity coefficient between the aboveground vegetation and the SSB decreased, and the number of species in the SSB was greater than that of the aboveground vegetation. Vegetation plays a decisive role in the initial development of a nebkha. When the nebkha develops to a certain extent, it reacts to the vegetation, thereby intensifying the differences in the composition of vegetation species in different parts of the nebkha and further affecting the SSB.

Structure, composition and carbon stocks of woody plant community in assisted and unassisted ecological succession in a Tamaulipan thornscrub, Mexico

BackgroundEcological restoration is a process that helps the recovery of an ecosystem that has been degraded, damaged or destroyed. The success of restoration actions depend on the understanding of the processes, mechanisms and factors that guide vegetation dynamics. The restoration of plant communities can be made by unassisted (passive restoration, where the community recover by itself) and assisted (active restoration) ecological succession. It is imperative to know the scope of both types of activities to guide future restoration actions by evaluating the properties and functioning of the intervened communities.MethodsVariance analysis of the carbon (C) stocks, basal area, canopy area, Shannon–Weaver index values, specific richness and abundance of three Tamaulipan thornscrub communities (assisted natural succession area, unassisted natural succession area and control area) was performed. Furthermore, a similarity analysis between the sampling areas using the floristic composition (abundance) was performed.ResultsIn total, 11 families, 17 genera and 20 species of vascular plants were registered. The richness of species and abundance ranked as follows per area: assisted ecological natural succession > control > unassisted ecological natural succession. The species composition between sampling areas showed a low number of common species between plant communities.ConclusionsThe values of species richness, diversity, abundance, basal area, and canopy area of the assisted natural succession vegetal community was statistical similar to the control plan community. The values of C stocks showed that assisted ecological succession could recover not only structure and composition attributes but also this key ecosystem property.

Флористическое разнообразие малых рек разной морфологии в зоне влияния подпора вод равнинного водохранилища

A comparative study of the floristic diversity of small rivers is of great importance in the assessment of their environmental state, which allows assessing the degree of pollution of the environment. The floristic diversity of the estuaries of the small rivers Korozhechna, Latka, Il’d’, and Chesnava, has been studied with special attention to the ecological groups and biological peculiarities of certain species. All the studied rivers flow into the Rybinsk Reservoir and have different morphology of the studied estuaries. The largest number of species has been recorded for the Chesnava River, the lowest, for the Il’d’ River. The representatives of families Poaceae, Cyperaceae, and Juncaceae evidence on the active overgrowing of shallow waters and periodically flooded coasts. Most of the species can grow on various soils, they are typical for water bodies with an oscillating water level and weak flow. The species-to-genus ratio, which is inversely proportional to the diversity of ecological conditions, is the highest in the Korozhechna River and the smallest in the Chesnava and Latka rivers. On the rivers Hydrophytes and hygrophytes dominated in the Korozhechna and Latka rivers; hygrophytes, hydrophytes, and hydrogelophytes, in the Il’d’ River; hygrophytes, mesophytes and hydrophytes, in the Korozhechna River. Such differences are explained by the peculiarities of environmental conditions. The highest similarity, by the absolute number of common species and by Jaccard coefficient, is found between the Chesnava River and the Latka River and between the Il’d’ River and the Latka River. According to hydrophytic cover index (HCI), near-water species dominated in the Chesnava River, a slight advantage in the proportion of the aquatic component of the flora was observed in the other rivers.

Study of Gas Production by Anaerobic Fermentation and Microbial Community Changes by In-Situ Microaerobic Desulphurization

The enhancement of biogas quality at low cost and high efficiency process was one of the purposes of biogas engineering. In this work, we designed a reactor for microaerobic desulphurization. We used this reactor to study the anaerobic fermentation in systems that used cow manure with total solid (TS) concentrations of 18.5%, 15% and 10%. The influence of anaerobic fermentation on the stability of gas production and the characteristics of the gas produced with different concentrations of fermentation materials was studied. The strain structure of the fermentation system was obtained by high-throughput sequencing and taxonomy was compared. The H2S removal results showed that the average rates of the H2S removal in concentrations of fermentation materials of 18.5%, 15%, and 10% TS were 99.2%, 97.8%, and 78.8%, respectively. 16SrRNA sequencing was performed in different fermented samples as well as a comparison between samples in order to determine the number of unique species (NUS) and the number of common species (NCS). By comparing TS 18.5 with TS 15 and TS 10 samples, it was determined that under fermentation conditions, NUS were 113 and 106, respectively. Whereas NUS were 31 and 41, respectively, when comparing TS 15 and TS 10. These demonstrated that the number of strain species in the fermentation system with TS 18.5% was far more than those found in the systems with low concentration of fermentation. Also, the ability for disturbance resistance of the microaerobic desulphurization system was stronger at high concentration of the fermentation.

Растительность в окрестностях мыса Желания (остров Северный архипелага Новая Земля)

Растительность в окрестностях мыса Желания (остров Северный архипелага Новая Земля)

Construction and Evaluation of a Graphene Oxide Functionalized Aminopropyltriethoxy Silane Surface Molecularly Imprinted Polymer Potentiometric Sensor for Dipyridamole Detection in Urine and Pharmaceutical Samples

A dipyridamole (DIP) based surface molecularly imprinted polymer (MIP) was synthesized and applied as a sensing agent in a sensing layer of a new modified potentiometric carbon paste electrode (CPE). The potentiometric modified CPEs (GO@SiO2-NH2-MIP/MWCNTs/CPE, where GO is graphene oxide and MWCNTs is multi-walled carbon nanotubes) showed an improved performance in term of Nernstian slope, selectivity and response time compared to the unmodified CPE. The response time of the sensor in the range of 2.5 × 10-8-1.1 × 10-2 M DIP was 20 s. The obtained DIP sensor showed low limit of detection (1 × 10-8 M), and satisfactory long-term stability (higher than 4 months). The practical application of the sensor was demonstrated by the determination of DIP concentration in urine samples and pharmaceutical preparations, with good precision and acceptable recoveries (96.0-103.0%). The prepared sensor showed high selectivity for DIP over a number of common species (aspirin, caffeine, ascorbic acid, glucose, urea, bipyridine, Na+, Fe3+, Mg2+, Ca2+ and K+).

Структура населення птахів байрачних лісів півночі Донецької області

The structure of bird communities of the oak forests was studied across seasons in 2004–2008 in northern parts of Donetsk Region. The data were gathered in Slov’iansk, Krasnyi Lyman, Oleksandrivka and Kostiantynivka districts, and within Kramatorsk town. The total length of transects was 192,3 km. The total of 97 oak forests with an area of 0,38 to 900,00 ha was surveyed. 68 bird species were recorded. 16 species are resident (23,5% of the total), 12 species (17,6%) are breeding and migratory, 12 species (17,6%) are migratory and wintering, 4 species (5,9%) were recorded only at passage, 2 (2,9%) species were winter visitors only and 21 (30,9%) species occurred only within breeding season. 51 bird species were recorded in the oak forests in breeding period, and among them Chaffinch (Fringilla coelebs Linnaeus, 1758), Great Tit (Parus major Linnaeus, 1758) and Yellowhammer (Emberiza citrinella Linnaeus, 1758) dominated. 44 bird species were registered in migratory period. Goldfinch (Carduelis carduelis (Linnaeus, 1758) and Great Tit dominated. In winter time 31 bird species were recorded and Greenfinch (Chloris chloris (Linnaeus, 1758) dominated. The number of common species was fairly stable across seasons and changed from 18 to 21 in different years. The share of common species in the total abundance was equally stable throughout a year at 90,99–97,14%. The share of dominant species in the total abundance varied from 14,9% to 44,8%. The presence of several raptor species e.g. Imperial Eagle (Aquila heliaca Savigny, 1809), White-tailed Eagle (Haliaeetus albicilla (Linnaeus, 1758), Black Kite (Milvus migrans (Boddaert, 1783), Goshawk (Accipiter gentilis (Linnaeus, 1758) is well distinctive for bird communities of of the oak forests of northern parts of Donetsk Region.

Tree monocultures in a biodiversity hotspot: Impact of pine plantations on mammal and bird assemblages in the Atlantic Forest

Forest plantations of fast-growing exotic species constitute an important economic activity in tropical and temperate regions of developing countries. Large areas of native forests and grasslands are being turned into tree plantations without assessing their impacts on natural communities. We evaluated the effects of replacing native forests by non-native pine (Pinus taeda) plantations on the diversity and composition of assemblages of terrestrial mammals and ground-dwelling and understory birds, in a forest productive landscape of the Upper Paraná Atlantic Forest of Misiones, Argentina. Camera-trap stations were deployed in three different “environments”: 53 in a continuous forest, 69 in forest fragments, and 62 in tree plantations. The evaluation focused on the effect of the environment, the structural complexity of the vegetation, the cost-distance (distance weighted by connectivity) to the continuous forest, the percentage of native forest within different radii, and the cost of human access (as a proxy for hunting pressure) on both mean species richness per station and species composition. Alpha diversity of the assemblages of each environment was estimated using Hill numbers (effective number of species): q0 = richness, q1 = number of common species and q2 = number of dominant species. Changes in community composition were evaluated by comparing the assemblages of the three environments using three similarity indices: Sorensen (q0 = similarity in species identity), Horn (q1 = similarity in common species), and Morisita-Horn (q2 = similarity in dominant species). For mammals and birds, richness was significantly higher in forest stations (both continuous and fragmented) than in those located in plantations. For both taxa, it also decreased with the distance to the continuous forest (but with a negative quadratic term in birds). Tree plantation stands contained biased and impoverished subsets of the original assemblages. Mammal composition was affected by the environment, the distance to the continuous forest, the proportion of native forest in the landscape, and human access. The bird assemblages of plantations were seriously affected, and their composition was also influenced by changes in vegetation structure. Alternative management practices (e.g. pruning, thinning) and landscape features can partially mitigate the negative effect of tree plantations on mammal and bird assemblages. Large areas of forest that function as population sources and forest fragments immersed in the matrix of plantations are strictly necessary to preserve the original native mammal and bird assemblages in the productive landscape. Promoting connectivity and improving hunting controls will also support their conservation.

Spatial patterns of seasonal distribution of Corvidae (the case of urban habitats)

Corvids in Zhytomyr city reach maximum density in the winter period. Rooks and Eurasian Jackdaws were the most abundant species in winter, usually feeding in multispecies flocks and forming collective roosts.Suburban green areas (buffer zones) were characterized by a considerably high diversity of Corvidae species: this habitat was occupied by all six species. We also registered the highest density of Eurasian Jays and Hooded Crows in this habitat. The green areas in the city center were also characterized by significant corvid density, especially during the breeding season. The maximum breeding density of Rooks was in these habitats, which held 6 of 12 identified urban colonies in Zhytomyr. We found that the European Magpies, Eurasian Jays, and Hooded Crows also had high breeding success here. Eurasian Jackdaws occurred here only in autumn and winter, when they fed together with Rooks on lawns, gardens, and parks. With stable snow cover the Rook density in habitats of the green areas decreased due to the depletion of food resources.The individual buildings zone of the city were characterized by the lowest density of all corvid species, except for European Magpies and Eurasian Jays. The number of common species (Rooks, Eurasian Jackdaws, and Hooded Crows) was low because of shortage of food resources, lack of sites for large roosting flocks and shortage of suitable nesting sites. However, Eurasian Magpies reached one of their highest densities in this habitat (12.8 birds/km2). This species was registered in habitats around private buildings all the year round, successfully nesting in the yards of private houses and on trees in the streets. Its breeding density was 11.2 birds/km2.During three years of research (2009–2012) the density of all corvids except for European Magpie, practically did not change, although we determined a slight positive trend for all the species. The strong increase in the number of Eurasian Jackdaws could be explained by the increasing density of wintering populations or due to the increasing number of migrants from more northern regions.

Late Ordovician jaw-bearing polychaetes from Anticosti Island, eastern Canada, and their biogeographic significance

The Upper Ordovician to lower Silurian shallow marine succession of Anticosti Island, eastern Canada, provides one of the most complete records across the Hirnantian in the world. This study reports a diverse assemblage of scolecodonts (polychaete jaws) from the upper Katian and Hirnantian Vauréal, Ellis Bay, and basal Becscie formations of western Anticosti. The collection of 10 samples includes ca. 30 species representing 10 families. The fauna is dominated by polychaetaspids, mochtyellids, paulinitids, and polychaeturids. The family Xanioprionidae and genera Pistoprion, Tetraprion, and Rakvereprion are documented for the first time from the Ordovician of Laurentia. The Anticosti polychaete fauna shows great similarity to the contemporaneous faunas of Baltoscandia. This is evidenced by a high relative abundance of mochtyellids and polychaeturids and a number of common species, thus suggesting that the closing Iapetus Ocean at that time did not constitute a barrier for the dispersal of jaw-bearing polychaetes. Some Laurentian influence is, however, indicated by the occurrence of hadoprionids. Distinct Katian Vauréal and Hirnantian Ellis Bay scolecodonts are likely reflecting faunal reorganization linked to local environmental changes rather than the initial phase of the Hirnantian mass extinction.

Examination of edge effects in a Cryptomeria fortunei plantation in Zhougong Mountain, western Sichuan

To investigate edge effects on community structure, species composition and diversity in an artificial forest, research was conducted on Zhougong Mountain, a forest park in western Sichuan, and a large fragmented plantation of Cryptomeria fortunei was selected as the sample plot. The average DBH (diameter at breast height), average height, average density, richness index (D) and Shannon-Wiener index (H) were used to evaluate edge effects. Based on a field survey, 5 transects (width = 10 m) were established from the edge to interior forest (gradient 1 to gradient 5), and 4 small plots (10 m × 10 m) were chosen in each transect using a random sampling method. Results showed that 111 species, belonging to 96 genera and 54 families were recorded in 20 small plots with a total area of 2,000 m. The following results were also found in this investigation: (1) The number of species decreased away from the edge to forest interior. (2) In terms of community structure, a decrease of average DBH was found in the tree layer with the increase of edge gradients. Average density followed the opposite pattern and no significant differences were found in average height. In the shrub layer, average density decreased with the increase of edge gradients and no significant differences were found in average height. Average density and height both decreased from the edge to interior forest in the herb layer. (3) Based on the analysis of species diversity, richness index (D) and Shannon-Wiener index (H) of the plantation, decreased values were generally found with an increase of edge gra•研究简报• 第 8 期 王德艺等: 川西周公山柳杉人工林群落的边缘效应 941 dients, and were much more obvious in the shrub and herb layer. Moreover, the number of common species and Sorensen’s similarity coefficient between edge gradients in the forest interior and edge 1 both showed a decreasing trend from the edge to interior forest. (4) Based on a comprehensive analysis, a clear change of community was found between edge 2 and edge 3, indicating that edge effects can reach 20 m into the fragmented patch of the Cryptomeria fortunei plantation.

First report of Beet western yellow virus on pepper in China.

Beet western yellows virus (BWYV, genus Polerovirus, family Luteoviridae) infects Beta vulgaris, Raphanus sativus, Capsella bursa-pastoris plus a number of common weed species. In August 2014, pepper plants (Capsicum frutescens) showing mosaic and crinkling of the young leaves were observed in greenhouses in Tangshan city, Hebei province (China). Samples were collected from eight symptomatic pepper plants and tested for viruses by RT-PCR using total RNA isolated with TRIzol reagent (Tiangen, China) and degenerated primer pairs to detect poty-, tospo-, tobamo- and poleroviruses (Cortez et al., 2001; Letschert et al., 2002; Marie-Jeanne et al., 2000; Zhou et al., 2011) and specific primers to detect Cucumber mosaic virus (CMV) (Wang et al., 2013). Potato virus Y and CMV were detected in all the samples and a 1412 bp amplicon was obtained from one sample with polerovirus primers PoconF (5′-TGYTCYGGTTTTGACTGG-3′) and PococpR (5′-CGTCTACCTATTTSGGRTTN-3′) designed in conserved sequences of ORF2 and ORF3, respectively (Zhou et al., 2011). Sequence analysis of the amplified fragment showed high nucleotide identity with a BWYV isolate from Korea (98%) (GenBank accession No. KM076647.1), followed by two BWYV isolates from Beijing (95-96%) (HM804471.1 and HM804472.1) and another BWYV isolate from USA (92%) (AF473561.1). To our knowledge, this is the first report on the occurrence of BWYV in Capsicum frutescens.

Biodiversity and ecology of soil fungi in a primary succession of a temperate coastal dune system

Soil fungal communities were studied in an actively developing coastal dune system at Goeree Island, the Netherlands. A shore to inland sampling transect was laid out, extending from coastal brackish marshes to recently formed foredunes to older dune pastures to adjacent woodlands. Soil samples from these biotopes were thoroughly characterized by analyzing physicochemical and microbial characteristics. Soil fungal community structure and composition were analysed by a combination of different phenotypic and genotypic methodologies (isolation of microfungi via a specialized soil washing technique and in situ observation of macrofungi, versus DGGE profiling and sequencing of multi-locus rDNA clone libraries). The results showed that fungal biomass tended to increase land-inwards along the gradient of maturity. The community structure was significantly correlated with progressive soil acidification land-inwards and with the exposure to brackish water in the coastal sites. Comparison between isolation and molecular datasets revealed that both methods were biased towards specific functional or phylogenetic groups. Most of the isolated fungi were common soil saprotrophic ascomycetes, while specialized fungi (biotrophic plant symbionts and pathogens, primary decomposers of recalcitrant organic matter, etc.) were only detected by molecular means. Phylogenetic specificity of PCR-based DNA profiling, on the other hand, strongly depended on primer selection. In spite of the relatively low number of common species that were identified among the isolated cultures and by clone library sequencing, as well as the potential biases of each characterization method, multivariate analysis on both isolation and molecular datasets yielded similar correlation patterns with the environment.

Two-sided edge responses of avian communities in an urban landscape

Impacts of habitat edges on wildlife populations have received considerable attention, yet few researchers have quantified changes in animal community structure on both sides of an interface between distinct habitats. To gain a better understanding of the ways in which species-specific responses scale up to produce community patterns across habitat boundaries, we examined the response of avian communities to forest-suburb edges in northeastern Illinois, USA. We surveyed bird assemblages using replicated point-transects (n = 21) that crossed boundaries between remnant forest patches and suburban residential areas in order to compare differences in community composition, species distributions, and densities. Forest and suburban bird communities were distinct, and community composition changed with distance-from-edge in forests but not suburbs. Abundances of many species that were common in the forest increased with distance-from-edge in the forest, whereas numbers of common species in the suburbs were largely unaffected by distance-from-edge. Using a new metric that we termed “tolerance,” we found many forest species avoided the edge and suburbs, and suburban species were present near the edge but did not venture far into forest. Overall, distance to the forest-suburb boundary was more influential in structuring avian communities in the forest. Some species of conservation concern crossed edges into the suburbs, suggesting that management activities may improve suburban biodiversity. Many other imperiled forest species, however, will only be retained in urban environments through the protection of forest interior habitat.

A Comparison of Fish-based Classification Schemes for Reference Streams and Rivers in Nebraska.

Proper assessments of lotic ecosystems depend on our ability to isolate natural differences from anthropogenic disturbances. We examined Nebraska river and stream classification strength, based on fish species, using multiple response permutation procedures for common classification strategies: ecoregions, watersheds, hydrologic-landscape regions, and assemblage structure from cluster analyses. Next, we tested the ecological interpretability of classification schemes using nonmetric multidimensional scaling ordinations and ANOVAs. Finally, we used nonparametric ANOVA to identify environmental predictors of overall fish assemblage structure. Hydrologic-landscape regions had the highest classification strength, but cluster groups had the most ecological interpretability based on the discreteness of the groups in ordination space and on the large number of common species that had different abundances across cluster groups. In addition, presence/absence data provided groups with more classification strength and interpretability than abundance data. Temperature, stream size, total phosphorus concentrations, and the percentage of fine substrates were significantly correlated to nonmetric multidimensional scaling ordinations and to overall fish structure in the multivariate ANOVA models. Cluster analyses using presence/absence were therefore the best classification scheme, and we identified the environmental variables that are likely to be useful for determining whether streams should have similar biotic assemblages. This information will be a valuable guide for separating natural variability in biotic assemblages from anthropogenic influences.

Asymptomatic Pyuria among Diabetics is a Growing yet an Ignored Concern: An Exploratory Study from Rural India

The comparative faunistic analysis of species diversity of family Gelechiidae in Islands of Peter the Great Gulf and in neighboring continental territories is made. The island fauna turned out depleted because of small size of islands, limited landscape diversity and impossibility of active moth migration due to their weak flying abilities. However the concentration of species diversity in islands is almost two orders of magnitude larger than that in continental part. The proportion of Gelechiid groups with certain type of geographic range in islands is similar to that in continental part, that is treated by recent their isolation. The fauna of every examined island is disharmonic, representing by some species from every genus and includes small number of common species that is interpreted by continual species extinction and an insignificant random drift from mainland.

OCCURRENCE OF BEET WESTERN YELLOWS VIRUS IN JAPANESE HOP (HUMULUS SCANDENS) IN CHINA

Beet western yellows virus (BWYV) naturally infects Beta vulgaris, Raphanus sativus, Capsella bursa-pastoris and a number of common weed species. In autumn 2011, Japanese hop [Humulus scandens (Lour.) Merr] plants showing mosaic symptoms on young leaves were observed in the West Campus of the China Agricultural University of Beijing (China). Total RNA was extracted from symptomatic leaves and screened by RT-PCR with degenerate primer pairs to detect poty-, potex-, tobamo-, cucumo-, polero- and tospoviruses. A specific RT-PCR product (1,384 bp) was obtained only with polerovirus primers designed to amplify a fragment including the partial RNA-dependent RNA polymerase (RdRp) gene, an intergenic non coding region and the coat protein (CP) gene (Zhou et al., 2011). Sequence analysis (GenBank accession No. KC210049) confirmed the presence of BWYV in the analysed samples. The CP gene of the BYWV isolate under study had the highest identity with a BWYV isolate from Inner Mongolia (92.1%) (EU636991) and another BWYV isolate from Beijing (90.6%) (ADR74372.1). whereas the partial RdRp sequence had the highest identity with a BWYV isolate from Beijing (98.3%) (EF051249.1). No RT-PCR products were obtained from healthy plants. To our knowledge, this is the first report on the natural occurrence of BWYV in H. scandens. As H. scandens is one of the most common weeds in China, management of BWYV in or near sugar beet fields or other crop hosts should include the removal of this weed.

Sampling Sufficiency for Fish Assemblage Surveys of Tropical Atlantic Forest Streams, Southeastern Brazil

AbstractKnowledge of the adequacy of field sampling protocols is critical for detecting species and assessing biological conditions. Several studies have been conducted to determine the appropriate electrofishing distance for estimating fish assemblage richness in temperate North American streams. We tested whether electrofishing 40 times the mean wetted channel width was sufficient for estimating species richness and developing precise metrics for Atlantic Forest streams in southeastern Brazil. We sampled 32 sites with differing gradients, substrates, and anthropogenic pressures. Our results show that 40 channel widths were not sufficient to estimate species richness in those systems, presumably because of the high number of rare species. However, 40 channel widths were sufficient for applying other metrics of assemblage condition (e.g., number of common species, percentage of tolerant individuals, percentage of Characiform species, percentage of Siluriform species, percentage of water column species, percentage benthic species, Shannon diversity, dominance). This suggests that 40 channel widths are an appropriate sampling distance for applying environmental assessment protocols to Atlantic Forest streams.