Arnold Móra

Variation of aquatic insect assemblages among seasons and microhabitats in Hungarian second-order streams

The assemblages of aquatic insects are important members of water ecosystems. Based on former studies among the most important factors structuring the assemblages are numerous abiotic ones, such as the sort and the particle size of the substratum. Most of the sampling protocols, e.g. AQEM, determine microhabitats based on those. Nevertheless, we have no information yet about whether or not these different, precisely determined microhabitats have different assemblages. In this study we compared the aquatic insect assemblages of different microhabitat types in three seasons using ADONIS and linear discriminant analyses. We proved that seasonal changes of abiotic factors had a major role in structuring the assemblages. In spring and summer the assemblages differed significantly, however, in autumn no significant differences were found. We supposed that the variation among the assemblages was due to the abundance patterns of frequent species instead of the presence of rare or sparse species. The indicator species analyses also corroborated this suppososition while symmetrical indicator species were not found.

Aquatic and semiaquatic Heteroptera (Nepomorpha and Gerromorpha) fauna of Greek holiday islands (Rhodes, Crete and Corfu) with first records of three species from Europe and Greece

A comprehensive survey on aquatic and semiaquatic bugs (Heteroptera: Nepomorpha and Gerromorpha) of three Greek holiday islands, Rhodes, Crete and Corfu, was conducted from 2007 to 2010 at 237 localities. In this paper, hundreds of detailed records for 30 taxa in nine families are given. The occurrences of Rhagovelia infernalis africana Lundblad, 1936 and Velia mariae Tamanini, 1971 are confirmed and recorded for the first time from Europe sensu stricto. Additionally, some notes on morphology, taxonomy and distribution of the European species of Rhagovelia and Velia are also given, Velia mariae is recorded for the first time not only from several Greek islands, but from continental Greece and Bulgaria as well. Gerris asper (Fieber, 1860), a common European species, was also found for the first time in Greece. Furthermore, new occurrence data are given for endemic taxa; Sigara nigrolineata mendax Heiss & Jansson, 1986 and Velia rhadamantha rhadamantha Hoberlandt, 1941 (whose distribution is restricted to Crete and small adjacent islands) are very common throughout Crete, whereas Ilyocoris cimicoides jonicus (Lindberg, 1922) apparently is rare in Corfu.

Highly variable abiotic environment induced changes in taxonomic and functional composition of headwater chironomid assemblages within a small mountain range

The spatial variability of Chironomidae larvae assemblages was investigated at 6 near-pristine, temperate headwaters in Hungary. Sites were located within a relatively small mountain range but belong to two different catchment areas characterized by highly variable abiotic conditions. We hypothesised there would be differences in taxonomic composition but not in functional composition between different catchment areas and aimed to assess the primary influencing spatial factors structuring the taxonomic and functional compositions of chironomid assemblages. The spatial distribution of chironomid assemblages was examined 4 times during a 1 year period at microhabitat to catchment scales. At each site, streambed morphology, physicochemical attribute, riparian vegetation, microclimate and hydrology data were collected. Three main traits (saprobic preference, stream zonation preference, functional feeding groups) were used to characterize the functional composition of chironomid assemblages. Sharp differences were detected in taxonomic composition between the two sides of the mountain range within a relatively small spatial distance and moderate, but statistically significant differences in functional composition between catchments. The observed spatial changes in taxonomic and functional composition of midges accompanied changes in physicochemical characteristics, riparian vegetation, microclimate and altitude. Internal microhabitat heterogeneity also played a major role in structuring the taxonomic and the functional patterns of chironomid assemblages.

Aquatic Macroinvertebrates of the Drava River and Its Floodplain

Due to the untouched and almost pristine conditions of the Drava region, to date 438 species belonging to various aquatic macroinvertebrate animal groups have been recorded from the Drava and its floodplain. Therefore the aquatic fauna of this area is among the richest in Hungary. The most unique species of the Drava is the caddisfly Platyphylax frauenfeldi, since its population along the river might be the last in the world. The occurrence of many rare, Natura 2000, protected or strictly protected species enhances the nature conservation value of the region. Unfortunately, the large number of non-indigenous species indicates the vulnerability of natural assemblages devastated by aquatic invasions. Moreover, the aquatic macroinvertebrate assemblages are vulnerable, and might be threatened by any unconsidered human action, especially measures of river regulation, since the change or loss of habitats might cause serious damage to the populations of rare species.

Livin' on the edge: the importance of adjacent intermittent habitats in maintaining macroinvertebrate diversity of permanent freshwater marsh systems

ABSTRACT Taxonomic and functional patterns of macroinvertebrate communities were investigated to reveal the importance of different habitat units within a marsh system in maintaining its macroinvertebrate diversity. Hydrogeomorphic units based on their functional characteristics were used to distinguish 3 types of aquatic habitats within the marsh system: (1) Core Unit (CU), a permanent inundation of a wetland in the central position of a marsh system; (2) Transitional Unit (TU), a seasonal to intermittent inundation of a wetland, with seasonal saturation; and (3) Satellite Unit (SU), seasonal depression wetlands with ephemeral to intermittent saturation. We hypothesized that communities in each Unit would have specific taxonomic and functional features. Species richness was highest in the TU, with unique community composition in the SU, and moderately high species richness characterized by a stable community with high taxonomic distinctness in the CU. The metacommunity of the entire marsh was nearly random with a substantial equilibrium between beta-diversity features: replacement and dissimilarity. Our results suggest that the combination of directly connected or isolated waterbodies in close proximity to a large core waterbody is likely to maintain the highest level of diversity. Each Unit has unique characteristics and provides habitats for species with different ecological traits; thus, different aquatic habitats of a marsh system should be considered together as one meaningful ecological entity.

Environmental and spatial drivers of beta diversity components of chironomid metacommunities in contrasting freshwater systems

Partition of beta diversity into components is a modern method that allows inferences about the underlying processes driving metacommunities. Based on two alternative approaches, we examined the patterns of beta diversity components of chironomids in relation to environmental and spatial gradients in three contrasting freshwater ecosystems. Beta diversity and its replacement component increased from environmentally less heterogeneous lake, through more complex wetland to stream network. Constrained ordination revealed that environmental heterogeneity and spatial processes explain some variation of the patterns of pairwise beta diversity components. Both beta diversity partitioning approaches emphasised the importance of habitat structure and food resource in structuring chironomid metacommunities. However, concurrent approaches provided contrasting results regarding the relative role of underlying mechanisms related to species replacement and richness. Therefore, further research is needed to clarify which of the beta diversity partitioning approaches should be preferred more widely in ecological studies.