No abstract

Springs are important freshwater habitats that provide refuge for many rare species. In this study, the fauna and abiotic parameters of 20 perennial springs in north-western Switzerland were investigated. Correlation of abiotic and macrozoobenthos data showed that physicochemical parameters had little impact on macrozoobenthic composition, whereas specific substrate parameters strongly influenced the composition of the macrofauna. Surprisingly, nonmetric multidimensional scaling did not reveal a grouping of springs with similar substrate composition or macrozoobenthic assemblages. However, discharge was identified as the factor significantly determining substrate and the composition of macroinvertebrate assemblages. This justifies the hypothesis that, variation in discharge is the disturbance factor governing the macrofaunal composition temporally and spatially within and between patches.

No abstract

No abstract

BackgroundWater mites are among the most diverse organisms inhabiting freshwater habitats and are considered as substantial part of the species communities in springs. As parasites, Hydrachnidia influence other invertebrates and play an important role in aquatic ecosystems. In Europe, 137 species are known to appear solely in or near springheads. New species are described frequently, especially with the help of molecular species identification and delimitation methods. The aim of this study was to verify the mainly morphology-based taxonomic knowledge of spring-inhabiting water mites of central Europe and to build a genetic species identification library.MethodsWe sampled 65 crenobiontic species across the central Alps and tested the suitability of mitochondrial (cox1) and nuclear (28S) markers for species delimitation and identification purposes. To investigate both markers, distance- and phylogeny-based approaches were applied. The presence of a barcoding gap was tested by using the automated barcoding gap discovery tool and intra- and interspecific genetic distances were investigated. Furthermore, we analyzed phylogenetic relationships between different taxonomic levels.ResultsA high degree of hidden diversity was observed. Seven taxa, morphologically identified as Bandakia concreta Thor, 1913, Hygrobates norvegicus (Thor, 1897), Ljania bipapillata Thor, 1898, Partnunia steinmanni Walter, 1906, Wandesia racovitzai Gledhill, 1970, Wandesia thori Schechtel, 1912 and Zschokkea oblonga Koenike, 1892, showed high intraspecific cox1 distances and each consisted of more than one phylogenetic clade. A clear intraspecific threshold between 5.6–6.0% K2P distance is suitable for species identification purposes. The monophyly of Hydrachnidia and the main superfamilies is evident with different species clearly separated into distinct clades. cox1 separates water mite species but is unsuitable for resolving higher taxonomic levels.ConclusionsWater mite species richness in springs is higher than has been suggested based on morphological species identification alone and further research is needed to evaluate the true diversity. The standard molecular species identification marker cox1 can be used to identify species but should be complemented by a nuclear marker, e.g. 28S, to resolve taxonomic relationships. Our results contribute to the taxonomical knowledge on spring inhabiting Hydrachnida, which is indispensable for the development and implementation of modern environment assessment methods, e.g. metabarcoding, in spring ecology.

1. Springs are distinct freshwater habitats that are threatened globally by human impacts, but are not included in standard freshwater assessment tools. This study analysed how the standard macroinvertebrate metrics currently used in biomonitoring programmes for running waters perform in springs with similar ecological qualities but with a different degree of hydromorphological modification.Macroinvertebrate assemblages were analysed in 50 riparian springs along the Crvcka River in the Dinaric karst.2. Most metrics analysed (ASPT, EPT fam , PTH fam , BMWP, STAR_ICMi, and Spring_ICMi) showed significant differences between hydromorphologically modified and natural, i.e. unmodified, springs.3. A self-organizing map (SOM), an unsupervised artificial neural network, was used for patterning and visualizing 10 environmental parameters and the metrics analysed.Most macroinvertebrate metrics, besides IBE (which did not show any pattern) and PTH fam (which showed an opposite trend), had significantly lower values in the spring group with the highest electrical conductivity and the lowest discharge.4. The study showed that hydromorphological modification does not necessarily lead to a loss of crenobiontic species, provided that the discharge and substrate composition remain suitable. Future coordinated conservation strategies must take into account the fact that spring species assemblages are sensitive to habitat structure and organic pollution, as has been achieved in Europe for rivers assessed under the Water Framework Directive. 5. Using multimetric indices, such as the new Spring_ICMi, may help to provide a framework for assessing the response of macroinvertebrate assemblages to human impacts. They may also help in assessing the success of measures used for the conservation and restoration of these threatened but highly valuable habitats. Further investigations should verify the suitability of such metrics in assessing the deterioration of springs globally.

The canyons in Dinaric karst are known to harbour a diverse aquatic fauna living in springs along the river mainstream. However, the knowledge on the ecology of these springs and also on the springs in mountainous areas of the Balkan Peninsula in general is poor. This study is focused on the macroinvertebrate assemblages of three different types of springs along the Cvrcka River (Republic of Srpska, Bosnia and Herzegovina). The aim of this study was to check whether existing criteria for regional spring zonations in Central Europe are applicable also for riparian springs with short springbrooks bordering high order streams. The macroinvertebrates were collected seasonally for one year at two different distances from the source: at the source, and approximately 2–3 m from the source (“springbrook”). At the spring sources, we found 59 species and higher taxa while in the springbrooks 61 species and higher taxa were recorded. Diptera represented the most abundant taxon, followed by Amphipoda and Trichoptera. No strong trend for the Margalef’s index for the spring source and springbrook was detected, while the Shannon’s diversity index increased in the springbrook of the studied springs. Our analysis did not prove significant differences between the macroinvertebrate assemblages from the source and springbrook. Based on faunistic data we suggest that small riparian springs with a short outflow likely do not exhibit true spring zonation but may show a “quasi-zonation” defined as a possible hidden differentiation between spring source and springbrook. Our study shows that criteria for spring zonation are not suitable for riparian springs bordering high order streams.

No abstract