Community assembly is determined by a combination of historical events and contemporary processes that are difficult to disentangle, but eco-evolutionary mechanisms may be uncovered by the joint analysis of species and genetic diversity across multiple sites. Mountain streams across Europe harbour highly diverse macroinvertebrate communities whose composition and turnover (replacement of taxa) among sites and regions remain poorly known. We studied whole-community biodiversity within and among six mountain regions along a latitudinal transect from Morocco to Scandinavia at three levels of taxonomic hierarchy: genus, species and haplotypes. Using DNA barcoding of four insect families (>3100 individuals, 118 species) across 62 streams, we found that measures of local and regional diversity and intraregional turnover generally declined slightly towards northern latitudes. However, at all hierarchical levels we found complete (haplotype) or high (species, genus) turnover among regions (and even among sites within regions), which counters the expectations of Pleistocene postglacial northward expansion from southern refugia. Species distributions were mostly correlated with environmental conditions, suggesting a strong role of lineage- or species-specific traits in determining local and latitudinal community composition, lineage diversification and phylogenetic community structure (e.g., loss of Coleoptera, but not Ephemeroptera, at northern sites). High intraspecific genetic structure within regions, even in northernmost sites, reflects species-specific dispersal and demographic histories and indicates postglacial migration from geographically scattered refugia, rather than from only southern areas. Overall, patterns were not strongly concordant across hierarchical levels, but consistent with the overriding influence of environmental factors determining community composition at the species and genus levels.

Some aspects of the biology and ecology (life cycle, feeding and production) of a population of Isoptena serricornis in the Rudava River (Slovakia) are studied, reported and discussed. The life cycle is annual, with slow growth in autumn-winter and fast growth in late summer and spring. The growth decreased two weeks before the Fall Equinox and increased two weeks after the Spring Equinox. The flight period spans from the end of May to the beginning of July. The presence of large sand particles in the gut of all studied nymphs is of note, and indicates that I. serricornis acts as a depositcollector species. Nymphal food is principally composed of detritus, unicellular organisms and, in nymphs of intermediate or large size, Chironomidae larvae. Adult food is composed fundamentally of different types of pollen grains. Males usually have lower food content than females. Annual production of this species (~694 -750 mg · m -2 ) is very high in relation to other previously studied Chloroperlidae. This is probably largely responsible for I. serricornis being one of the most abundant components of the macroinvertebrate community in its habitat in the Rudava River. A negative correlation between production and temperature was observed.

A multimetric assessment system was developed to determine the ecological status of two types of stream in the Carpathian ecoregion following the requirements of the WFD. The organic pollution gradient was defined using Canonical Correspondence Analysis. Classification based on physical, chemical and biological data divided the tested sites into two stream types with subsequent grouping into several ecological quality classes. From all the metrics tested, 17 for the East Carpathian streams and 15 for the West Carpathian streams, from seven metric categories, were included in the resulting multimetric index. Different kinds of response to degradation (linear, unimodal, exponential) were observed. The Saprobic index (Zelinka and Marvan), Rheoindex (Banning, with abundance classes) and Index of Biocenotic region, showed the best discriminatory ability for both stream types.

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The nymphal biology (life cycle, secondary production and feeding) of a population of Protonemura intricata was studied in a calcareous stream with almost constant temperature (7-8 °C) through the year at Prosiek valley (Chočské Vrchy Mts., West Carpathians, Slovakia). The results were compared with those previously known for this species in other areas. According to our data, the species has a complicated life cycle consisting of two cohorts with different duration (probably a cohort splitting). This life cycle seems to be uncommon among the Plecoptera, which usually has simple univoltine or semivoltine life cycles, and could be probably attributed to the constant temperature regime similar to that of tropical environments. One factor, the photoperiod length, was positively correlated with monthly growth rates. The nymphal growth varied throughout the year, but the highest growth was in late spring and summer, and the lowest was in winter. The annual secondary production was very high (909.4 mg · m -2 ) despite not being the most frequent taxon in the stream. The highest monthly production values were observed in the autumnal-winter period (November-December) due to massive hatching of nymphs. The lowest production values were observed in late summer and early autumn. Analyses of gut contents showed that this species behaves mainly as gatherer-collector, but also as shredder and, occasionally, as scraper. Changes in the gut content composition were detected in relation to the size. Comparing our results with those of the literature, it can be inferred that different populations of P. intricata can show notable differences in their life history when inhabiting places with different thermal conditions. IntroductionOne of the most important aspects for understanding freshwater ecosystems is the biology of the species that live in them. In this context, the study of the life history of single species is essential in order to achieve a full knowledge of the ecosystem itself and the relations within it. Many studies have tried to reach this goal through generalizations taken from the study of a reduced number of species, assuming that the rest of the members of their genus or family behave in the same manner. As pointed out by several authors (ZWICK, 1981;STEWART and STARK, 1993), this is neither a good approximation nor an appropriate * Corresponding author 58 Z. KOZÁČEKOVÁ et al.

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Abstract:The gut contents of adult Xanthoperla apicalis and Siphonoperla torrentium were analysed. X. apicalis females eat mainly pollen, while males feed principally on detritus and pollen. Adults of S. torrentium, regardless of sex, eat mainly pollen. The presence of animal remains (claws and leg and antennae segments of Arthropoda) in the gut of several individuals of both species was observed and discussed.