Due to their specific physical and chemical properties of water and soil soda pans of the Vojvodina region represent a unique type of habitats. Salinity is a major structuring factor which strongly affects species richness. Many halotolerant, alkalotolerant and halophilic organisms, together with numerous eurytopic elements inhabit these kinds of ecosystems. In this review we tried to compile the biodiversity information from various literature sources and give the best representation of what can be expected to be found in these shallow, temporary and intermittent aquatic environments. Only a few groups of organisms are fairly well studied, while many others are insufficiently investigated or the knowledge of them is lacking altogether. Best investigated are certain groups of algae and birds. Bacterial communities, as well as many invertebrate groups, are poorly studied or not investigated at all. Characteristic elements of flora and fauna, together with growing anthropogenic pressures make soda pans prime targets for protection. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 47007 III]

We present new data on rare riffle beetle findings (Coleoptera: Elmidae) from the Balkan Peninsula. Larvae and adult elmid beetles were collected during 2007-2018. The following Balkan countries were included in the study: Serbia, Bulgaria, Romania and Bosnia and Herzegovina. Riffle beetle fauna of the Balkan Peninsula is poorly explored due to a lack of data, particularly in southern and eastern areas. The main objective of the study was to add to the knowledge of this group of aquatic insects. New records of 7 riffle beetle species are provided, as follows: Stenelmis puberula Reitter, 1887, Stenelmis consobrina consobrina Dufour, 1835, Potamophilus acuminatus (Fabricius, 1792), Elmis syriaca zoufali (Reitter, 1910), Elmis rioloides (Kuwert, 1890), Limnius intermedius Fairmaire, 1881 and Limnius opacus Muller, 1806, with notes on their occurrence, habitats and co-occurrence with other riffle beetle taxa. Because of the scarcity of species findings, their disjunct distribution and specific ecological requirements, some riffle beetle species are becoming more vulnerable to pronounced human impact. Accordingly, adequate habitat protection is necessary for rare riffle beetle species and for their conservation on the Balkan Peninsula, particularly in small streams.

This study focused on the aquatic insect orders that serve as biological indicators. Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, and Odonata were studied with their relationships to physical, chemical, hydrological and morphological variables in 14 streams on three Croatian mountains: Papuk, Medvednica and Psunj. From 675 samples collected in three dominant sediment microhabitats (e.g., macrolithal and mesolithal) in each stream, we identified 130 macroinvertebrate taxa. The most abundant group was Ephemeroptera (36 taxa). Aquatic insect assemblages between Papuk and Psunj showed higher similarity due to the geographical proximity of these two mountains, which is expressed as spatial connectivity. In spring, greater variability and diversity of investigated aquatic insects were observed due to the phenology of studied insects. The combination of environmental and morphological properties (e.g., oxygen concentration and substrate type) had the most significant influence on shaping the assemblage of aquatic insects of Psunj, while morphological properties were the most important in shaping aquatic insect assemblages on Papuk (e.g., streambed width) and Medvednica (e.g., elevation). Baetis sp. was the dominant taxon in summer, Protonemura montana in spring, and Leuctra sp. in autumn. Seasonal shifts in environmental conditions lead to functionally unique communities that utilize the pool of available seasonal resources. The dominance of feeding groups varied by season, with scrapers and collector–gatherers being most prevalent in summer, while shredders were dominant in spring. The results on the relationships between environmental characteristics and species richness, functional structure, and distribution of aquatic insects in mountain streams provide important clues for future research and conservation strategies in these vulnerable ecosystems.

The paper presents the results of morphometric study of the riffle beetle Elmis maugetii Latreille, 1802 in response to hydraulic pressure. The following species morphometric characters were analyzed: head length, prothoracic width and total body length with respect to measured hydrological parameters (water level, sampling depth and current discharge). A total of 155 E. maugetii adult specimens from six typical riffle beetle streams in Serbia were examined during investigated period (2014-2015). Among measured hydrological parameters, it was found that only current discharge affects specimen size-a larger specimens were found in streams characterized by higher flow velocity. The main goal of the study is to assess the influence of current discharge on species morphometric variability.