Ponds are an essential freshwater habitat for plants and animals, and they play a central role in maintaining high regional biodiversity. In addition, ponds have many other functions relating to education, recreation, economy, hydrology, culture and aesthetics. Despite their importance, relatively few resources are invested in pond conservation in Europe. Furthermore, the scientific basis for the management and conservation of ponds is currently weak compared to the information available for other freshwater habitats. Some national environment agencies from countries such as France, the United Kingdom and Switzerland, have recently developed elements of a national strategy for pond conservation. There is now need to strengthen and develop these initiatives and to build a common framework in order to establish a sound scientific basis for pond conservation in Europe. The European Pond Conservation Network (EPCN, www.europeanponds.org) was established at the First European Pond Workshop in Geneva, October 2004. The mission of the Network is to promote awareness, understanding and conservation of ponds in a changing European landscape. Specifically the objectives of the Network are: (1) to exchange information on pond ecology and conservation between researchers, managers and practitioners, (2) to promote understanding of pond ecology by encouraging the development and coordination of fundamental and applied research, (3) to raise the profile of ponds and guide national and supra-national policies for their protection, (4) to promote effective practical pond conservation, and (5) to disseminate information on the importance, attractiveness and conservation of ponds to the people. The "Pond Manifesto" presents the background and the motivations of the EPCN.

The programme LIFE Nature "Conservation and restoration of habitats of the Rhine fringe" (2002-2005) focussed on the assessment of the conservation status of terrestrial and aquatic habitats. Along the Rhine fringe, the degree of connection between waterbodies and the river main channel determined the water flow (surface or phreatic waters, flow velocity) and induced flood disturbances (hydromorphological quality, scouring effect). A new typology based on metrics characterizing the conservation status, was proposed for the upper Rhine floodplain. Seven physical and biological metrics were selected: specific richness, presence or absence of rare, polluto-tolerant and exotic species, species abundance, degree of connection, and trophy level defined by the macrophyte community. Aquatic macrophytes surveys were conducted at 315 sites along the Rhine French fringe. Multiple correspondence analysis and discriminant analysis were used to define metrics scores in a preliminary network of 129 macrophytes surveys stands. Metrics were combined to give a measure of the conservation status of the 315 sites. Five classes of the conservation status have been defined from degraded to excellent status. The mapping of the conservation status was realized to answer the question addressed by the program “Life Nature”. We discuss on the choice of the metrics and their justification in the definition of the conservation status. The method was tested in the fluvial hydrosystem of Ill river, the main tributary of the Rhine river in the Alsace floodplain, and compared to the French trophic index based on macrophytes, IBMR.

This paper contains a compilation of the average values of 24 geographical, physical, chemical, biological and productivity parameters collected and processed during 12 years of research on 9 freshwaters and salmastricol lakes situated on the Romanian seaside of the Black Sea. The paper emphasizes the discussion of those parameters indicating the current degree of eutrophication of these lakes. It shows that the lakes situated in the southern part of the Romanian seaside (Limanu, Valea Arsa and Hagieni) are the least affected by the process of eutrophication; they are followed by the northern lakes (Razim and Sinoie) which are supplied with the waters of the Danube river, after these have been filtered in the floodable areas of the Danube Delta. The process of eutrophication is found to be stronger in the waters close to the agricultural areas and the urban localities from the Romanian seaside of the Black Sea.

The stability of occurrence, abundance and dominance of fish was compared between two sampling periods, 1963-66 and 2002-04 in two lowland rivers from the Warta/Odra system (Poland): the Widawka and its tributary Grabia (95.8 and 77.3 km long, respectively). The Widawka system has been under strong influence of a brown coal strip mine since the 1970s. Long stretches of the upper Widawka and of its certain tributaries were changed into concrete canals, which receive daily 660 000 m3 of water disposed by the strip mine. The Grabia maintained its natural character. On the basis of the abundance of fish species, the Kohonen artificial neural network almost perfectly separated fish samples collected in 1963-66 from samples collected in 2002-04, which means that: 1) the differences in ichthyofauna between these two sampling periods were more drastic than spatial differences between the severely modified Widawka and the natural Grabia, and 2) in general, ichthyofauna at the most modified sites in 1963-66 was in better condition than at the least modified sites in 2002-04. In 1963-66, the species, roach, gudgeon, bleak and dace composed together 70% of the total fish number, while in 2002-04 the same joint dominance was gained by roach, perch and stone loach. The analysis of temporal changes in the Widawka and Grabia Rivers focused on the following 3 fish groups: (1) Non-psammophilous rheophils (NPR), which are most vulnerable to human-induced modifications, which is why their decline and/or extinction are typical for unbalanced lotic ecosystems. In this study, the total dominance of NPR decreased 5 times; (2) Psammophilous rheophils (stone loach and gudgeon), which often predominate in degraded smaller streams. In this study, the dominance of stone loach increased 3 times and was highest in the most affected stretches of the Widawka River, including those that had been canalised. Gudgeon was often dominant at moderately modified sites of the Widawka; (3) Roach and perch, whose high dominance is typical for disturbed larger rivers, which was supported also in this study by the fact that both species were most dominant in 2002-04. The dominance of roach increased almost twice and was highest in the lower courses of both rivers. A significant increase in abundance was recorded for perch, whose dominance was highest in the canalised section of the Widawka. The described changes were deep enough to influence the hardly sensitive CDI, Simpson and Shannon indices, which indicated a significant increase in dominance and a decrease in diversity of fish assemblages over the last 4 decades.

We studied the morphology of two ‘flesh-eating’ Chydoridae Anchistropus emarginatus Sars, 1862 and Pseudochydorus globosus (Baird, 1830), using populations from Belgium, with particular attention to the structure of the trunk limbs. Both genera belong in subfamily Chydorinae, and both have morphological adaptations with implications for the interpretation of limb morphology in the subfamily. Anchistropus has a large number of specific characters, many of which directly relate to the animal’s habit of feeding on Hydra. In Pseudochydorus globosus, specializations are less numerous. A redescription of both species is offered, with an aim at allowing future comparisons with populations outside the Palaearctic, where cryptic species are expected to occur.

Freshwater habitats of the Italian Alps are largely unexplored and further floristic-ecological surveys are needed to clarify the role of freshwater lichens in these environments. This applies especially to springs, since they seem to be suitable for a relatively high number of aquatic species due to their ecological stability. The present work is focused on springs in an alpine region, and is centered on: (a) floristics of freshwater lichens of the Italian Alps, (b) ecological and morphological information on potential indicator species for calcareous and siliceous springs. The study was carried out in the eastern Italian Alps on 36 perennial springs. Single springs proved to host a surprisingly low number of species, while at regional level the entire pool of investigated springs host a relevant lichen flora representing 45% of the freshwater lichens of the Italian Alps. One species is new to Italy and 3 are new to Trentino-Alto Adige. Biodiversity conservation measures should therefore be planned at regional level, including a whole network of sites in different altitudinal belts and with different substrates. Verrucaria elaeomelaena and V. funckii are the most frequent species on calcareous and siliceous springs respectively. They are suggested as potential indicator species, since they proved to be indicative of the main physical, ecological and hydrochemical features of their habitat. A detailed morphological description of these two species is also provided in order to enhance their identification by environmentalists.

Intraspecific variability in life-history traits was investigated comparing four geographically isolated populations of the shrimp Palaemonetes argentinus (Crustacea, Caridea, Palaemonidae) in the Province of Buenos Aires, Argentina. One population inhabits a creek (Vivoratá Creek, VC), which drains into the brackish coastal lagoon Mar Chiquita; three others live in inland lakes (Lakes Chascomús, LC; La Brava, LB; Los Padres, LP). Female size at the onset of sexual maturity, both realized and actual fecundity (i.e. number of eggs in an early stage of embryonic development and number of freshly hatched larvae per female, respectively), as well as the size of freshly hatched larvae were consistently largest at VC, intermediate at LC and LB, and lowest at LP. The opposite pattern was found in egg loss (estimated as difference between realized and actual fecundity), being lowest at VC, highest at LP, and intermediate in the other two populations. Initial embryonic dry weight (W) was higher at VC than in all other populations. However, the W of freshly hatched larvae was similarly high at VC, LC and LB, but significantly lower at LP. Intraspecific variation in life-history traits, in particular between shrimps from VC (lotic, slightly brackish; highly variable salinities) and those from inland lakes (lentic; low but stable ion concentrations) are discussed in relation to local variation in hydrological and other ecological conditions that may wield differential selection pressures in the life-history evolution of a species with a wide range of ecological and geographic distribution.