The main aim of the present review is to synthesise the present level of knowledge on the hydrobiology of springs in the Alps. Springs are usually small, but complex and taxa rich. They have a mosaic structure, a high degree of individuality and an azonal character, due to the peculiar physicochemical stability. Springs are ecotones linking an aquifer to the uppermost section of a surface running water system. Due to adaptations, of which stenothermy is the most frequent, representatives of many groups of plants and animals have in springs their exclusive (crenobionts) or favourite (crenophiles) habitat. This leads to a peculiar longitudinal distribution of organisms. In spite of this complexity, springs (in particular high elevation springs of the Alps) have received much less attention than other types of inland waters. They are endangered habitats, being menaced by a series of direct impacts (primarily water abstractions) and indirect impacts. The classical Steinmann-Thienemann ecomorphological types are still used with differences in the physical and chemical characteristics and in the biota. In the Alps rheocrene springs (where current velocity is one of the most relevant factors and the importance of the fringing semi-aquatic habitats is reduced) are the most frequent. However, in nature, most springs are transition types among the three traditional ones and these can now be assessed thanks to procedures considering mainly the substrate particle size. The physicochemistry of springs is characterised by limited seasonal fluctuations and determined by the characteristics of the aquifer and by indirect (especially airborne contaminants) and direct impacts. Many groups of organisms are well represented and include indicators of the trophic and acid-base status, of hydrogeology, hydrological stability and biological integrity. The groups with the highest proportions of specialised taxa are mosses, water mites, dipterans, hydrobioid snails and caddisflies. Attempts are being made to add to the traditional spring types hydrochemistry and vegetation and to the regional faunistic types, diatom-based types, to combine different approaches and to consider also functional ones, such as the distinction between POM and mosses' springs. Given the high proportion of spring-specific taxa, we propose to use the zoobenthos, especially water mites, for an evaluation of the biological integrity of springs, whilst autotrophs, and in particular diatoms, which are the most widespread and taxa-rich group, can provide excellent indicators of eutrophication, acidification and ionic strength. This would require the calibration of the most promising diatom-based procedures to the spring environment and improvement of the knowledge on the taxonomy and distribution of key zoobenthos groups in the Alps. Other areas where further research is required are the definition of integrated spring-types, the potential for recovery of autotrophs in restored springs, functional aspects, the applicability of paleolimnological techniques to springs an...

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Özet Bu çalışmada, Atractides inflatipes (Lundblad, 1956) dişilerinin bazı yapısal özellikleri örneklerimiz üzerinden gözden geçirilerek yeniden düzenlenmiş, çeşitli organlarının şekilleri çizilmiş ve ölçümleri yapılmış, ayrıca türün dağılımı üzerinde durulmuştur. Abstract In this study, some structural features of Atractides inflatipes (Lundblad, 1956) females based on our material were revised, some body parts were measured and illustrated, distribution of the species was also evaluated.

1. The Hydrachnidia (water mites, Hydracarina) are the most diversified group of the Acari in freshwaters and are abundant and speciose in lotic habitats. Lower-order streams may contain up to 50 species (including benthic and hyporheic forms) and small springs up to 20 crenobiont species. 2. Water mites are grouped into 8 superfamilies, 50 families, 300 genera containing more than 5 000 species. Representatives of all superfamilies (about 3 000 species worldwide) occur in lotic ecosystems, although most lotic species belong to the Hydryphantoidea, Lebertioidea and Hygrobatoidea. Identification of water mite families, genera and subgenera, throughout the world, is possible using taxonomic publications. Keys to species level are also available but mainly for local faunas. Descriptions of larvae and deutonymphs are rare. 3. The life cycle of the Hydrachnidia is unique among the Acari and is similar to that of holometabolous insects, with a heteromorphic parasitic/phoretic larva and two pupa-like resting stages. The larva parasitises mainly insect hosts with apparently no strict hostspecificity. Deutonymphs and adults are voracious predators feeding mainly on insect eggs, insect larvae and microcrustaceans. In some cases, water mite parasitism and predation may substantially affect the structure of lotic communities. 4. Most species show a high degree of habitat/microhabitat specialization. Temperature, current-speed, substratum type, physiographic and geomorphological factors are the major determinants of species composition in water mite communities. 5. The complex, fully aquatic, life cycle and multilevel biocoenotic interactions make water mites well suited for the detection of physical and chemical disturbances to lotic ecosystems. 6. Future research should address the distribution, biology, autecology, community dynamics and ecological interactions of lotic water mites.

Summary 1. The distribution, species richness and ecology of spring‐dwelling water mites in Italy were investigated with the aim to better elucidate the role of spring habitats to sustain high levels of biodiversity and their contribution to freshwater biodiversity at a local and regional scale. 2. More than 300 springs in different geographic areas (Alps, Central and Southern Apennines, Sicily and Sardinia), were examined with a total of 163 water mite species recorded. 3. Species richness in each area ranged from 33 species on Sardinia to 77 on Sicily. The highest diversity was found in the Gran Sasso (Central Apennines). The proportion of crenobionts (species strictly bound to this type of habitat) exceeded 50% in almost all the areas investigated. 4. A diverse (up to 20 species per spring) and highly specialised mite fauna was observed in undisturbed rheocrenes and in natural springs of intermediate typology (rheohelocrenes and rheopsammocrenes). In springs subjected to human impacts (pasture, deforestation, alteration and transformation of spring sources) species richness declined and crenobionts were replaced by unspecialised crenoxenes. 5. The zoogeographic importance of spring habitats is confirmed by the presence of 18 endemic species and by members of genera with an interesting disjunct and relict distribution. 6. A comparison with other geographic areas suggests that springs contain a significant fraction of the total number of species found in freshwater habitats and may contribute almost one third of regional freshwater biodiversity. The presence of endemic crenobionts and rare taxa highlights the importance of these habitats in maintaining high levels of biodiversity as well as their contribution to a better understanding of biodiversity patterns in freshwaters.