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Vorkommen der Gattung Synchaeta Ehrenberg, 1832 (Rotifera: Monogononta: Synchaetidae) in den Seen Südtirols
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Permafrost und seine Auswirkungen auf die Ökologie von Hochgebirgsseen
Full text linkThe present study, carried out in the framework of the Interreg IV Italy-Austria project “permaqua”, investigates the effects of the melting of permafrost and particularly of rock glaciers on
the ecology of high altitude lakes. The ecological structure of 15 lakes, influenced by rock glaciers to different extents, was compared with the one of 18 unaffected lakes used as reference. The chemical-physical and biological analyses were performed on samples taken in each lake during a single late summer or autumnal sampling. All
lakes influenced by melting rock glaciers showed surprisingly high concentrations of sulfate, magnesium, calcium and, in the lakes with acidic pH, increased concentrations of heavy metals were also found. The composition of phytoplankton and phytobenthos was mainly determined by pH and nutrient conditions rather than by the abovementioned changes in chemical omposition induced by melting permafrost and zooplankton densities were unfortunately too low to allow any meaningful comparison. However, differences in the composition of the littoral auna were found between lakes with and without rock glacier influence. The littoral macrozoobenthos of the lakes not influenced by rock glaciers was generally composed of a higher number of species, additionally showing a more regular distribution. The higher diversity score was found to be due to the presence of EPT taxa and other sensitive species. Together with the lower species diversity, rock glacier influenced lakes also showed a different composition of the chironomid communities with dominance of insensitive species. The structure of the meiozoobenthos between lakes with and without rock glaciers present in their watersheds was also found to be different and again characterized by the dominance of species with broad ecological valence. The indirect influence of high sulfate concentrations and other substances delivered to the lake by the rock glacier outflows probably produce environmental conditions which provide a competitive advantage to less sensitive species. The present study showed that melting rock glaciers exert significant chemical changes in high altitude lakes, which induce modifications of the biotic elements very likely affecting the ecosystem functioning of these lakes. The data collected in the course of the present study contribute to the knowledge of the local alpine aquatic flora and fauna and will prove useful for future studies, particularly those related to the investigation of the effects of climate change
Comunità planctoniche in bacini artificiali alpini in rapporto all’utilizzo antropico della risorsa acqua
No full textSono state analizzate le variazioni spazio-temporali delle comunità planctoniche in tre bacini artificiali dell'arco alpino (regionr trentino Alto Adige) in relazione all'uso della risorsa acqu
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
I laghi di montagna come indicatori dei cambiamenti globali: le ricerche nei siti della rete LTER-Italia
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