Characterization of the microbial community of lotic organic aggregates ('river snow') in the Elbe River of Germany by cultivation and molecular methods

Aerobic and anaerobic cultivation techniques, 16S rDNA-based phylogeny, and fluorescent in situ hybridization were used to describe the phylogenetic diversity and physiological versatility of lotic microbial aggregates ('river snow') obtained from the river Elbe. In the course of the year the 'river snow' community changed. It was characterized by a great bacterial diversity in spring, the predominant occurrence of algae in summer and reduction of the total bacterial cell count in autumn and winter. In all 'river snow' samples, more than 70% of the bacteria counted with the general DNA stain DAPI also hybridized with the Bacteria-specific probe EUB338. In situ analysis of the bacterial 'river snow' community with a comprehensive suite of specific rRNA-targeted probes revealed population dynamics to be governed by seasonal factors. During all seasons, beta-Proteobacteria constituted the numerically most important bacterial group forming up to 54% of the total cell counts. In contrast to this, the relative abundance of other major bacterial lineages ranged from 2% for the order Planctomycetales to 36% for Cytophaga-Flavobacteria. Cultivation of 'river snow' under aerobic and anaerobic conditions with a variety of different media resulted in the isolation of 40 new bacterial strains. Phenotypic and phylogenetic analyses revealed these new strains to be mostly unknown organisms affiliated to different bacterial phyla. Application of newly developed specific oligonucleotide probes proved the cultivated bacteria, including clostridia and the numerically abundant beta-Proteobacteria, as relevant in situ members of the 'river snow' community.     

用硅藻群集指数(DAIpo)和河流污染指数(RPId)评价珠江广州河段的水质状况

用硅藻计于1990年采集珠江广州河段的9个采样点的附着硅藻群落．共得硅藻24个属,170个分类单位,其中,适腐性种8个,广腐性种84个,仍腐性种78个．群落相似性聚类分析表明,位于前、后航道中部的员村（st3）,新造（st8）,沙浴村（si10）三点的硅藻群落结构是为相似,向上,下游相似性逐渐减小．用硅藻群集指数（DAIpo）和河流污染指数（RPId）对各采样断面的水质进行分析表明：大盛（st12）和莲花山（st5）两点受污染最轻,属β-寡污带,黄沙点（st2）污染最严重,属α-中污带．对照点鸦岗（St1）也受到一定的污染,属α-寡污带,其它点的污染程度在α-寡污带与β-中污带之间．DAIpo值与BODS存在着显著的负相关（r＝0．86）．珠江广州河段的前、后航道的污染程度相差不大（RPId=56．42,56.26）,均属中度污染．     

Phenological mapping in a topographically complex landscape by combining field survey with an irradiation model

Abstract. A phenological map has been prepared for the Podyjí/Thayatal National Park, located on the border between the Czech Republic and Austria. The area is characterized by V-shaped river valleys deeply incised into a gently undulating landscape. Five stages of phenological development were defined, based upon phenological spectra of plant communities in late April; 96 sites, more or less regularly spaced over the area, were assigned to one of these stages using field observations of these spectra. Potential direct solar irradiation was calculated from a digital elevation model for a 25 m x 25 m grid extending over the study area. A method was developed for interpolation of phenological observations by weighted regression of phenology on the irradiation model. This interpolation enables the prediction of the local stage of phenological development across the study area without levelling out phenological patterns dependent upon small-scale topographic variation. Spring phenological events appear to be more advanced in the valleys (except for steep north-facing slopes) than in the adjacent landscape. Possible climatic processes underlying this pattern are discussed with emphasis on temperature inversions in the river valleys. Cold-air-drainage inversions reported from the valleys are probably too infrequent and of too short duration to delay plant phenology. The combined effects of advanced phenology and the increased risk of spring frost injury due to these inversions in the valleys may be an explanation for local distributional patterns of flora and vegetation.     

DNA barcoding of freshwater ichthyoplankton in the Neotropics as a tool for ecological monitoring

Quantifying and classifying ichthyoplankton is one of the most effective ways of monitoring the recruitment process in fishes. However, correctly identifying the fish based on morphological characters is extremely difficult, especially in the early stages of development. We examined ichthyoplankton from tributaries and reservoirs along the middle stretch of the Paranapanema River, one of the areas most impacted by hydroelectric projects in the Neotropics. Matching DNA sequences of the COI gene (628–648 bp) allowed us to identify 99.25% of 536 samples of eggs (293) and larvae (243) subjected to BOLD‐IDS similarity analysis with a species‐level threshold of 1.3%. The results revealed 37 species in 27 genera, 15 families and four orders, some 23.8% of documented fish species in the Paranapanema River. Molecular identification meant that we could include data from egg samples that accounted for about 30% of the species richness observed. The results in this study confirm the efficacy of DNA barcoding in identifying Neotropical ichthyoplankton and show how the data produced provide valuable information for preparing plans for conserving and managing inland waters.     

Assessment of Heavy Metal Pollution in Water and Sediments from the Ghalechay River,Baychebagh Copper Mine Area,Iran

The concentrations of selected heavy metals in sediments and waters in Baychebagh copper mine were determined using ICP-OES. Except for Co, the average concentrations of Cd, Cu, Pb, and Zn in sediments from the Ghalechay River in the district exceed the world-average shale and continental upper crust value. Enrichment factors for Pb, Cu, and Cd were significantly enriched in sediments, indicating environmental contamination. Geoaccumulation index calculated for different sampling stations indicates that the sediments are unpolluted with respect to Co and Zn while unpolluted to moderately polluted with Cu and highly polluted with Pb and Cd. The Sediment Quality Guidelines (SQGs) suggest that Cd and Pb may pose the highest risk for the environment. Sequential extraction analyses of sediments revealed that Cu, Co, Pb, and Zn bound to extractable, carbonate, reducible and oxidizable fractions are lower than residual fraction. About 10% of the total Pb was associated with the exchangeable fraction, indicating remobilization, while Cd (89%), Pb (73%) Co (58%), Cu (76%), and Zn (68%) closely associated with the residual and oxidizable fractions, resulting in their environmental immobility. The residual forms are not expected to be released under normal conditions in the river and could be considered an inert phase.     

Evolutionary dynamics of ecological niche in three Rhinogobio fishes from the upper Yangtze River inferred from morphological traits

In the past decades, it has been debated whether ecological niche should be conserved among closely related species (phylogenetic niche conservatism, PNC) or largely divergent (traditional ecological niche theory and ecological speciation) and whether niche specialist and generalist might remain in equilibrium or niche generalist could not appear. In this study, we employed morphological traits to describe ecological niche and test whether different niche dimensions exhibit disparate evolutionary patterns. We conducted our analysis on three Rhinogobio fish species (R. typus, R. cylindricus, and R. ventralis) from the upper Yangtze River, China. Among the 32 measured morphological traits except body length, PCA extracted the first four principal components with their loading scores >1.000. To find the PNC among species, Mantel tests were conducted with the Euclidean distances calculated from the four principal components (representing different niche dimensions) against the pairwise distances calculated from mitochondrial cytochrome b sequence variations. The results showed that the second and the third niche dimension, both related to swimming ability and behavior, exhibited phylogenetic conservatism. Further comparison on niche breadth among these three species revealed that the fourth dimension of R. typus showed the greatest width, indicating that this dimension exhibited niche generalism. In conclusion, our results suggested that different niche dimensions could show different evolutionary dynamic patterns: they may exhibit PNC or not, and some dimensions may evolve generalism.     

长江鲢、鳙个体发育过程中的表型变化

采用多元分析方法,对采自长江老江河国家级四大家鱼原种场255尾1—5龄鲢、鳙的30项形态度量数据进行了分析。聚类分析显示,鲢可明显地聚成欧氏距离相对较远的1龄组和2—5龄组,鳙也可聚成欧氏距离较远的1、2龄组与3—5龄组。判别分析显示,144尾鲢个体对所聚类的两个组别的判别准确率高达98.0%,111尾鳙个体对所聚类的两个组别的判别准确率也达90.7%。这表明,在幼体向成体的发育过程中,鲢和鳙在形态上均存在着两个具有显著差异阶段。单因素方差分析显示,鲢两个组别之间有18个参数差异极显著,4个差异显著,其中10个显著或极显著地变小,12个显著或极显著地变大。鳙两个组别间有极显著和显著差异的参数分别有14个和3个,其中极显著或显著差异变小和变大的分别有12个和5个。这表明在鲢、鳙个体发育过程中,分别有73.3%和56.7%的特征参数具有生长异速现象。因此,在根据形态鉴别物种、分析种群差异、确立种质标准和作生长退算时,均应考虑所选用特征的生长异速现象。     

Mallard Response to Experimental Walk-In and Shooting Disturbance

ABSTRACT Spatial and temporal closures of anthropogenic activities are a common management strategy to increase waterfowl usage of an area. However, empirical evidence, specifically how individual waterfowl respond to disturbance, is lacking to support their efficacy. We exposed radiomarked mallards (Anas platyrhynchos) to walk-in, shooting, or no disturbance along the South Platte River corridor in Colorado, USA, from September to February during 2006–2007 and 2007–2008. Mallards exposed to shooting disturbance had greater mean flight distance after disturbance (FDAD) during September-November (4.58 km, 95% CI = 3.55–5.62) than December-February (3.04 km, 95% CI = 2.51–3.58) and were 35% and 17% greater than mean FDAD of mallards exposed to walk-in disturbance, respectively. Walk-in and shooting disturbance had a similar effect on return rates, and disturbed mallards had higher (0.09–0.41) movement probabilities away from and lower (0.15–0.20) probabilities of returning to treatment locations than controls. Probability of presence of disturbed mallards was 37% lower than controls during the daytime but was equal at night. Mallards exposed to walk-in (0.38 [95% CI = 0.30–0.46]) and shooting (0.23 [95% CI = 0.17–0.30] disturbance had low return rates the first afternoon after a disturbance compared to controls (0.71 [95% CI = 0.65–0.77]). A high proportion of mallards exposed to walk-in (0.75 [95% CI = 0.67–0.83]) and shooting (0.70 [95% CI = 0.64–0.76]) disturbance returned to treatment locations in ≤1 day. Managers may be able to more effectively manage disturbance regimes by 1) accounting for surrounding lands within <10 km, especially lands within <5 km, 2) being conscientious when establishing regulations that will affect levels of disturbance 1–2 days after a previous disturbance, and 3) considering shooting and walking disturbance equally for refuge design.     

Biogeography and diversity among montane populations of mouse shrew (Soricidae: Myosorex) in Tanzania

We assess variation in morphological and molecular characters among three species of Myosorex (the mouse shrew) –Myosorex geata, Myosorex kihaulei, and Myosorex zinki– as a means to test previously proposed biogeographic hypotheses for Tanzanian ‘sky islands’ and systematic hypotheses for Tanzanian mouse shrews. We analyse 17 cranial and dental variables using multivariate statistics and perform phylogenetic and phylogeographic analyses on sequences of mitochondrial and nuclear DNA; samples are drawn from every known Tanzanian population of Myosorex. Morphometric and phylogenetic analyses reveal that M. zinki is distinct, but that currently isolated populations of M. geata and M. kihaulei are relatively similar to one another, and may not have been isolated over geological time scales. Analyses of molecular variance identify statistically significant, but limited, genetic variation within and between isolated populations of M. geata and M. kihaulei. Between two putative regional biogeographic boundaries, greater genetic variation is explained by grouping populations on either side of the Ruaha River than by grouping populations on either side of the Makambako Gap. Our results are in agreement with recent studies illustrating the close relationship between faunas of the Southern Highlands and southern Eastern Arc Mountains, diminishing the apparent importance of the Makambako Gap as a historical biogeographic barrier. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 669–680.     

乌江河岸带维管植物区系的初步研究

对乌江河岸带维管植物区系的研究结果表明,河岸带共有维管植物69科187属302种,其中蕨类植物9科10属16种,裸子植物1科1属1种,被子植物59科176属285种。生活型以草本为主,其次是灌木。科、属、种的分布区类型多样,在科级水平上有7个类型和4个变型,在属级水平上有13个类型和10个变型,在种级水平上有15个类型和13个变型。地理联系较为广泛,与北温带植物区系联系最为紧密,其次是泛热带植物区系和东亚植物区系。科、属的优势现象较为明显。该河岸带植物区系呈亚热带性质,与热带植物区系有较高的亲缘关系。