The EU Water Framework Directive requires assessment of the ecological quality of running waters using macroinvertebrates. One of the problems of obtaining representative samples of organisms from streams is the choice of sampling date, as the scores obtained from macroinvertebrate indices vary naturally between seasons, confounding the detection of anthropogenic environmental change. We investigated this problem in a 4th order calcareous stream in the western Carpathian Mountains of central Europe, the Stupavskyṕ otok brook. We divided our 100 m study site into two stretches and took two replicate samples every other month alternately from each stretch for a period of 1 year,

The EU Water Framework Directive requires assessment of the ecological quality of running waters using macroinvertebrates. One of the problems of obtaining representative samples of organisms from streams is the choice of sampling date, as the scores obtained from macroinvertebrate indices vary naturally between seasons, confounding the detection of anthropogenic environmental change. We investigated this problem in a 4th order calcareous stream in the western Carpathian Mountains of central Europe, the Stupavskyṕ otok brook. We divided our 100 m study site into two stretches and took two replicate samples every other month alternately from each stretch for a period of 1 year,

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.

Abstract:We analysed the influence of environmental stress (mainly deforestation of catchment due to windstorm) on taxonomic structure as well as composition of functional groups (FG) based on zonation preferences and feeding types of caddisfly species in 11 streams (12 sites) with various environmental conditions situated in the High Tatra Mts, Slovakia. Using Spearman correlation, we confirmed an expected positive association between taxonomic and functional groups richness (Ri), diversity (Shannon -Wiener Index) (Di) and equitability (Eq), but not with habitat diversity (HQA indices). By testing measured physiographical, physico-chemical and hydromorphological factors using CCA analysis we found that stream order and temperature best explained the functional and taxonomic structure of caddisfly assemblages. The occurrence of Rhyacophila glareosa decreased with increasing daily mean water temperature positively correlated with deforestation, whereas R. tristis (dominating at sites most affected by erosion) showed the opposite pattern. Composition of functional groups based on zonation preferences and feeding types distinguished well near natural sites from impacted ones, dominated by crenal/rhithral predators, and explained more of the overall variance of the species-environment relationships than taxonomic composition of caddisfly assemblages.

In this study we describe how the river morphology of seven High Tatras streams has been influenced in different ways by a severe windstorm that occurred in November 2004. A control site situated in an undisturbed area is compared with six sites in windstorm damaged areas. In 2009-2010 River Habitat Survey (RHS) was used to assess the character of 500 m lengths of stream and to derive associated morphological indices (HQA, HMS sensu Raven 1998, RHS indices sensu Vaughan 2010). Large amounts of large woody debris in the channel influenced the streams despite most of it having been removed after the windstorm. Streams situated in deforested valley slopes were probably more affected by erosion; they had higher amounts of transported inorganic matter and also depositional bar features. Some changes in land-use had occurred with streams situated on the south-east side of the High Tatras having a more uniform banktop vegetation structure than the other streams. Distinct secondary succession of bank top vegetation was observed along windstorm influenced streams. The highest percentage of shrubs occurred where impacted streams remained untouched. Morphologically, the streams most affected by windstorm are those situated in deforested steep valley slopes that are affected by erosion and siltation.