Pelagic rotifers of Lake Glubokoe from 1897 to 1984

After alteration in the pattern of drainage of run-off from the surrounding swamps and changes in the colour and transparency of the Lake Glubokoe water, the previously epilimnial Trichocerca similis, Conochilus unicornis and Keratella cochlearis showed a shift of their maximum numbers to deeper layers. Pompholyx sp. and Trichocerca capucina, which are regarded as indicators of eutrophic waters, have disappeared from the pelagic zone of the lake and Conochilus hippocrepis, Synchaeta pectinata, Gastropus stylifer, Asplanchna herricki, Ascomorpha ecaudis, Ascomorpha saltans, Euchlanis dilatata and Trichocerca porcellus have made their appearance. Most of the new species are considered to be indicators of oligotrophic conditions. However the total density of pelagic rotifers remained at the same level. Apparently the establishment of the new species of rotifers was possible due to some ‘rarefaction’ of the epilimnion, the disappearance of predaceous Mesocyclops leuckarti and the invasion of the pelagic zone by Peridinium cinctum.     

A form-function analysis of photon capture for seaweeds

A large material of planktonic and semiplanktonic micro-crustaceans from various type of waters in south and central Sweden was computerized. The more frequent species were listed according to pH-preference and relation to humic content measured as mg Pt/l. Species indicating oligotrophy have their optima just below the neutral point, eurytopic ones around this level, while the eutrophic species Daphnia cucullata and D. magna were closely correlated with higher pH-levels. No really extreme pH-preference was observed. There is no link between trophic indication and the ranking list for humic content. Most planktic species occur at lower humic contents and semiplankters at higher.     

Effects of ecological flooding on the temporal and spatial dynamics of carabid beetles (Coleoptera, Carabidae) and springtails (Collembola) in a polder habitat

Within the scope of the Integrated Rhine Program an ecological flood gate and channel was inserted into the polder "Ingelheim" to enhance animal and plant diversity. In 2008, carabid beetles and springtails were collected, using pitfall traps, to measure the effects of ecological flooding and a strong precipitation event at a flood-disturbed and a dry location in this area. At both localities, xerophilic and mesophilic carabid beetle species were dominant throughout the study period. The total number of individuals of hygrophilic species was comparatively constant, while species number increased, partly due to the changed moisture conditions caused by ecological flooding and strong precipitation. Carabid beetle diversity and evenness decreased marginally when ecological flooding was absent. Springtails represent a less mobile arthropod order, and as such the impact of ecological flooding was stronger. An increase in both numbers of species and individuals of hygrophilic and hygrotolerant species occurred in the flood-disturbed location after ecological flooding. After the sites at both locations had dried, the number of individuals belonging to these species declined rapidly. In contrast to carabid species, the strong precipitation event showed no influence on hygrophilic springtail species. Thus, collembolan diversity and evenness decreased markedly in the absence of flooding. We showed that ecological flooding has an influence on the spatial and temporal dynamics of different arthropod groups that inhabit the polder "Ingelheim". These findings demonstrate the importance of using different arthropod groups as bioindicators in determining the ecological value of a particular polder design.     

Ecology of Foliicolous Lichens at the “Botarrama” Trail (Costa Rica), a Neotropical Rain Forest. I. Species Composition and its Ecogeographical Implications1

A total of 217 species of typically foliicolous lichens were found at the “Botarrama” trail, a premontane rain forest in the Braulio Carrillo National Park, Costa Rica. The species composition confirmed the classification of this study sice as transitional between lowland wet and montane rain forest. In terms of species tichness, the foliicolous lichen flora was dominated by the families Gomphillaceae (Calenia, Echinoplaca, Gyalideopsis, and Tricharia), Trichotheliaceae (Porina and Tricbothelium), and Pilocarpaceae (Byssoloma and Fellhanera). The most frequent species were Porina mirabilis (including its supposed anamorph Phyllophiale alba), Gyalectidium filicinum, Porina rufula, and Strigula platypoda. A large proportion of the species was rare. Frequency distributions based on area cover corresponded well to general community models by closely fitting a log-normal approximation. Half of the species had narrow ecological amplitudes while more than 70 percent exhibited a wide geographical distribution, thus making che study site representative of a Neotropical rain forest. The use of foliicolous lichens as indicators of altitudinal zonation is discussed.     

Taxonomy‐free molecular diatom index for high‐throughput eDNA biomonitoring

Current biodiversity assessment and biomonitoring are largely based on the morphological identification of selected bioindicator taxa. Recently, several attempts have been made to use eDNA metabarcoding as an alternative tool. However, until now, most applied metabarcoding studies have been based on the taxonomic assignment of sequences that provides reference to morphospecies ecology. Usually, only a small portion of metabarcoding data can be used due to a limited reference database and a lack of phylogenetic resolution. Here, we investigate the possibility to overcome these limitations using a taxonomy‐free approach that allows the computing of a molecular index directly from eDNA data without any reference to morphotaxonomy. As a case study, we use the benthic diatoms index, commonly used for monitoring the biological quality of rivers and streams. We analysed 87 epilithic samples from Swiss rivers, the ecological status of which was established based on the microscopic identification of diatom species. We compared the diatom index derived from eDNA data obtained with or without taxonomic assignment. Our taxonomy‐free approach yields promising results by providing a correct assessment for 77% of examined sites. The main advantage of this method is that almost 95% of OTUs could be used for index calculation, compared to 35% in the case of the taxonomic assignment approach. Its main limitations are under‐sampling and the need to calibrate the index based on the microscopic assessment of diatoms communities. However, once calibrated, the taxonomy‐free molecular index can be easily standardized and applied in routine biomonitoring, as a complementary tool allowing fast and cost‐effective assessment of the biological quality of watercourses.     

Assessment of environmental quality by the diversity of epiphytic lichens in a semi-arid mediterranean area (Val Basento, South Italy)

The results of a bioindication study based on the diversity of epiphytic lichens in a semi-arid area of South Italy are presented. The area features the presence of an industrial zone located in a rural context. The survey was performed in 20 sampling sites. The lichen diversity values (LDV) were determined by the frequencies of all lichen species within a sampling grid placed on tree trunks. Lichens demonstrated a condition of environmental alteration extending to the industrial zone, and tending towards a recovery in the rural surroundings. The survey also showed evidence of eutrophication all over the study area.     

Characterization of Pb and Cd contamination in the feces and feathers of rook (Corvus frugilegus) and the scalp hair of residents in Qiqihar,northeastern China

The concentrations of Pb and Cd, and trace elements (Cu and Zn) in the urban topsoil, rook (Corvus frugilegus) feces and feathers and human scalp hair were analyzed to examine the potential ecological risk posed by Pb and Cd on local residents of Qiqihar City, northeastern China. Results revealed that the Cd concentrations in the topsoil were ranged from 0.14 to 3.55 mg kg^?1 dry weight (dw). The maximal geoaccumulation indices [a value from logarithmic (a measured metal content/1.5 × background content of the metal in this region), introduced by Muller] of Cd exceeded 3.5, which suggested that this region was seriously contaminated by Cd. The corresponding average detectable concentrations in C. frugilegus feathers and feces were 1.38 and 3.97 mg kg^?1 dw for Pb and 1.04 and 0.69 mg kg^?1 dw for Cd. High Pb and Cd concentrations, respectively, ranging from 7.46 to 24.9 mg kg^?1 dw and from 0.35 to 0.92 mg kg^?1 dw were also detected in the human scalp hair samples. These high Pb and Cd concentrations in C. frugilegus and local people were possibly associated with local industrial wastes and vehicle exhausts. The external tissues (feces and feather) of the rook species can be considered as an indicator of potential Cd toxic risk in this species; however, the human scalp hair is not a reliable biomarker for risk of Pb and Cd in the human being. Effective measures should be established to reduce the inputs of Pb and Cd into the urban environment and to protect the health of local people.     

Empirical relationships between cladoceran fauna and trophic state in thirteen northern German lakes: analysis of surficial sediments

The cladoceran faunas from 13 northern German lakes (the Plön district) of different trophic levels were analysed using the bosminid and chydorid remains in the surficial sediment as an integrated sample of the total lake fauna. In the dimictic lakes, a shift occurred in the composition of planktonic Cladocera from Bosmina coregoni, including morphs with a mucro, to predominance of Chydorus sphaericus and Bosmina c. thersites as trophic state increased. In the benthic Cladocera (Chydoridae), there was a decrease in species diversity, in the percentages of phytophilous species and in the portion of species that are typical of clear water lakes, but there was an increase both in the number of mud dwellers and species that are typical of polluted lakes. No positive correlation was found between mean depth of the lakes and the planktonic/littoral ratio.     

Relationships between macrophytic vegetation and physical features of river habitats: the need for a morphological approach

The aim of this paper is to study the relationships between the physical features of rivers and the distribution of macrophyte vegetation. Field work was undertaken at 207 stations along the Scorff River and its tributaries, a salmon river system in southern Brittany (western France). The physical features were considered using a principal component analysis (PCA). Stepwise multiple regression models made it possible to assess their relationships with the botanical data. The first five axes of the physical PCA (used as explicative variables) were initially linked to the most frequently surveyed species, then to their eco-morphological types, and, finally to Arber’s (1920. Water Plants. A Study of Aquatic Angiosperms. Cambridge Univ. Press, Cambridge, 414 pp) morphological classification. It was concluded that plant morphology was closely related to these environmental factors. This could contribute to the development of predictive models for plant distribution and could increase the knowledge of reference vegetation related to bioindication systems.