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The functional feeding groups of rotifers as biological indicators in different water bodies are increasingly studied. The aim of this study was to assess the spatial and temporal patterns of Rotifera functional feeding guilds in relation to the environmental conditions in Lake Dojran. Pelagial rotifers of high abundance (110 ± 98 ind./L) obtained remarkable share (78%) in the zooplankton assemblage. They consisted of 18 species, where ten species are microphagous and was mainly comprised of the most abundant rotifers Brachionus diversicornis and Keratella quadrata in summer and autumn. The other 8 species are raptorial and have a significantly lower abundance. The microphagous rotifers occupied water layers from the surface to 4 m depth while raptorials prefer surface layers due to low transparency of only 0.5 to 1.8 meters. A correlation analyses revealed significant relationship between the microphagous rotifer abundance and the concentration of nutrients (TP and TN). The dominance of microphagous rotifers and other zooplankters indicated increased productivity in the shallow Lake Dojran. The findings of this study reveal that the functional group approach can be useful assessing tool of ecological processes in the shallow freshwater ecosystems

Eight Glacial Lakes within Albanian part of Adriatic Sea basin were subject of rotifer fauna survey in the period of 2018-2021. All of the lakes are located at altitudes above 1610 m except Lake of Dushku (1380 m). A total of 31 rotifer taxa were identified. Some of the identified taxa are new records for the Albanian inland water fauna and they include: Lecane latissima, Cephalodella gibba, Notholca squamula and Euchlanis dilatata lucksiana. Among the species the most dominant one were Keratella cochlearis (7 lakes), Lecane lunaris (7 lakes) Keratella quadrata (6 lakes), Brachionus quadridentatus (4 lakes), Notholca squamula (4 lakes), Filinia longiseta (4 lakes) and Lepadella patella (4 lakes). Following revealed data there is a linkage among rotifer species richness along different altitudinal distributions of lakes, where Lake of Dushko (1380 m) is distinguished by 16 taxa, while Lake of Valamare (2070 m) with four taxa. There is undergoing eutrophication process accelerated by cumulative anthropogenic impact including deforestation, fire events, erosion and siltation, where the most affected one is Lakae Dragani where 4.3 mg/l dissolved oxygen and PO43- - P (μg/L) was at rate of 9.03. The current survey enforces the recognition of ecological and social importance of continental small water bodies and further on it appeals for the conservation needs these aquatic ecosystems.

Lakes and ponds increased habitat heterogeneity and, in particular, invertebrate biodiversity. Both ecosystems, peculiarly in the karst region are sensitive to diverse anthropogenic impacts reflected in an increase of nutrients, as one of the most pronounced detorioration of standing waters. Zooplankton (Rotifera, Cladocera, Copepoda) plays an important and pivotal role in the the foodwebs of both, deep and shallow waterbodies, thus are reliable indicators of the water quality, according to their traits: diversity, abundance, biomass, size and feeding structure. In this survey, rotifer traits across three types of threatened ecosystems were assessed: (i) deep karst lakes of Balkan Peninsula (Plitvice Lakes and Visovac Lake, Croatia ; Shkodra Lake, Albania ; Ohrid Lake, Macedonia) ; (ii) permanent shallow waterbodies in temperate climate (inland Croatia) and (iii) ephemeral waterbodies in Mediterranean climate (Adriatic Sea, Croatia). Overall, trends of deteriorated water quality were exhibited across studied ecosystem, reflected in decreased biodiversity, increased abundance (up to three species), decrease in the specimen’s body size and transition of feeding preferences, from algivorous to detritivorous. In deep karst lakes still prevailed large-sized algivorous rotifers (genera Synchaeta, Polyarthra, Trichocerca), however with increased trophic state small-sized detridivores overtook domination. Abundance:biomass anaylysis indicated notable deterioration particularly in Mediterranean ponds with dominance of high abndance of small-sized detritivorous rotifer specimens. In shallow waterbodies of both climates submerged macrophytes enhanced diversity and water quality, while fish mainly showed negative impact. Conclusively, results of studied ecosystems suggested importance of rotifers in their interactions with other zooplankters, aquatic organisms and environmental conditions as significant factor in the assessment of ecosystem functioning, as well as in the lake restoration.

Great share of karst area is situated in the Mediterranean region. Recently, due to high turistic pressure and climate changes freshwater ecosystems, particularly lakes and ponds, undergo drastic, negative environmental changes. Unfortunately, rotifers are still understadied component of those threatened ecosystems, instead they play an important and pivotal role in the the foodwebs of both, deep and shallow waterbodies, and they are reliable indicators of the water quality, according to their traits: diversity, abundance, biomass, size and feeding structure. In this survey, rotifer traits across three types of threatened ecosystems were assessed: (i) deep karst lakes of Balkan Peninsula (Plitvice Lakes and Visovac Lake, Croatia ; Shkodra Lake, Albania ; Ohrid Lake, Macedonia) ; (ii) permanent shallow waterbodies in temperate climate (inland Croatia) and (iii) ephemeral waterbodies in Mediterranean climate (Adriatic Sea, Croatia). Overall, trends of deteriorated water quality were exhibited across studied ecosystem, reflected in decreased biodiversity, increased abundance of euryvalent rotifers (up to three species), decrease in the specimen’s body size and transition of feeding preferences, from algivorous to detritivorous. In deep karst lakes still prevailed large-sized algivorous rotifers (genera Synchaeta, Polyarthra, Trichocerca), however with increased trophic state small-sized detridivores overtook domination. Abundance:biomass ratio indicated notable deterioration particularly in Mediterranean ponds with dominance of high abundance of small-sized detritivorous rotifer specimens. In shallow waterbodies of both climates submerged macrophytes enhanced diversity and water quality, while fish showed negative impact. Conclusively, results of studied ecosystems suggested importance of rotifers in their interactions with other zooplankters, aquatic organisms and environmental conditions as significant factor in the assessment of ecosystem functioning, as well as in the lake restoration.

Small standing freshwaterbodies (SWB) prevailed across inland landscape, and zooplankton (Rotifera, Cladocera, Copepoda) presents their important biotic component. In this study we compared SWB in different latitudinal and climate regions (temperate and Mediterranean), with the aim to assess their resilience and recovery availability in a changing climate. Shallow waterbodies in both regions were selected by different morphometry, nutrients, macrophyte coverage, and fish stock. Results revealed that ecosystem heterogeneity caused by macrophyte coverage increased zooplankton diversity, irrespective of the climatic region. The opposite trend was observed in the case of fish presence, which decreased zooplankton diversity in both climates. Salinity is indicated as a specific driver in the Mediterranean region and it negatively impacted diversity. Along a latitude, the zooplankton abundance:biomass ratio indicated pronounced deterioration and higher densities of small-sized species in warmer regions in comparison to colder ones. The obtained results suggested a significant contribution of zooplankton to the biodiversity of shallow waterbodies, and Mediterranean SWB were recognized as ecosystem of higher risk in the ecosystem recovering. Importance of SWB in the functioning of aquatic and adjacent terrestrial ecosystem should point supporting the protection and sustainability of these vulnerable and valuable aquatic ecosystems.

Anthropogenic freshwater habitats may provide undervalued prospects for long?term conservation as part of species conservation planning. This fundamental, but overlooked, issue requires attention considering the pace that humans have been altering natural freshwater ecosystems and the accelerated levels of biodiversity decline in recent decades. We compiled 709 records of freshwater mussels (Bivalvia, Unionida) inhabiting a broad variety of anthropogenic habitat types (from small ponds to large reservoirs and canals) and reviewed their importance as refuges for this faunal group. Most records came from Europe and North America, with a clear dominance of canals and reservoirs. The dataset covered 228 species, including 34 threatened species on the IUCN Red List. We discuss the conservation importance and provide guidance on how these anthropogenic habitats could be managed to provide optimal conservation value to freshwater mussels. This review also shows that some of these habitats may function as ecological traps owing to conflicting management practices or because they act as a sink for some populations. Therefore, anthropogenic habitats should not be seen as a panacea to resolve conservation problems. More information is necessary to better understand the trade?offs between human use and the conservation of freshwater mussels (and other biota) within anthropogenic habitats, given the low number of quantitative studies and the strong biogeographic knowledge bias that persists.

Zooplankton assemblages (Rotifera, Cladocera, Copepoda) have been assessed in over 30 shallow lakes and ponds, from temperate to Mediterranean regions of Europe (Poland, Croatia, Albania, North Macedonia, Greece). We presumed that zooplankton diversity, ecological and functional trait differences will correspond with environmental specificity more than geographical distance. Thus, the main idea was to compare different latitudinal and climate regions (temperate and Mediterranean), in order to provide insight into the possible future function of shallow lakes in a changing climate. Shallow waterbodies in both regions were selected by different area, depth, macrophyte coverage, phytoplankton biomass and fish stock with the aim to distinguish both climate and environmental specific factors affecting zooplankton. Preliminary results revealed that ecosystem heterogeneity, associated with macrophyte coverage, increased the diversity of zooplankton, irrespective of the climatic region. The opposite effect was observed in the case of fish presence, which in both climates decreased zooplankton diversity. Salinity is indicated as a specific driver in the Mediterranean region and it negatively impacted diversity. Along a latitude, the zooplankton abundance:biomass ratio indicated pronounced deterioration and higher densities of small-sized species in warmer regions in comparison to colder ones. The obtained results suggested a significant contribution of zooplankton to the biodiversity of shallow waterbodies and the pressing need for supporting the protection and sustainability of these vulnerable and valuable aquatic ecosystems.

We report for the first time that the freshwater mussel Microcondylaea bonellii (Férussac, 1827) functions as a suitable host for the European bitterling Rhodeus amarus (Bloch, 1782). Given the recent expansion of R. amarus in Europe, the possible physiological cost (e.g. competition for oxygen, reduction in water circulation, and consequent impairment of filter-feeding) of this interaction may further affect the already poor conservation status of M. bonellii populations.