Ana Savić

Mayfly (Insecta: Ephemeroptera) community structure as an indicator of the ecological status of the Nišava river (Central Balkan Peninsula)

Mayfly taxa are widely accepted as bioindicators of water quality, due to the wide variety of substrates they live on and high chances of detecting the pollution impact by assessing their community structure. Ephemeroptera samples and physicochemical data were analysed for 12 sites along the 151 km long stretch of the Nišava River in southeastern Serbia during a one-year period. Twenty eight morphologically distinct taxa belonging to eight genera were identified. The dominant genera were Baetis (35.27%) and Ephemerella (29.44%). The Ephemeroptera community structure analysis of samples from the Nišava River has shown a clear dependence of the mayfly community on the habitat type, physical and chemical parameters, and the season. The lowest Shannons diversity index was estimated for the localities with the lowest percentage of the solid substrate and the highest average content of phosphorus and nitrogen.

Studies on eucrenal-hypocrenal zonation of springs along the river mainstream: A case study of a karst canyon in Bosnia and Herzegovina

Abstract 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.

Six species in one: evidence of cryptic speciation in the Hygrobates fluviatilis complex (Acariformes, Hydrachnidia, Hygrobatidae)

Abstract Water mites of the genus Hygrobates are widely distributed in all biogeographic regions except the Antarctic. Palaearctic Hygrobates species with reticulated soft integument generally have been considered as representatives of one common and widely distributed species, Hygrobates fluviatilis Strøm, 1768. Based on partial COI sequences (DNA-barcodes) and statistical analysis of morphological data, we show that these mites belong to six distinct lineages. Two of them are widely distributed in Central Europe: Hygrobates fluviatilis here redescribed based on a neotype designated from the type locality in Norway, and a species new to science, H. arenarius Smit & Pešić. The four remaining lineages represent additional species new to science that appear to have more restricted distributions: H. corsicus Pešić & Smit (Corsica, Sardinia), H. marezaensis Pešić & Dabert (Montenegro, Albania, Croatia), H. turcicus Pešić, Esen & Dabert (Turkey), and H. persicus Pešić & Asadi (Iran, E Turkey). Statistical morphometric analysis reveals that the latter two species cannot be separated on morphological characters and should be considered true cryptic species. We provide data concerning biology and geographical distributions together with a key to all species of the complex.

Ecological patterns of water bug (Hemiptera: Heteroptera) assemblages in karst springs : a case study from central Montenegro

Abstract The composition of water bug communities from 32 springs located in the central part of Montenegro was investigated. Twenty five species were identified, including 13 reported as new to Montenegro. The most common species were Hydrometra stagnorum and Velia sp. (Gerromorpha). Our study in the central part of Montenegro revealed that environmental and faunistic classification of karstic springs based on water bug communities may not correspond with each other. According to environmental characteristics, springs were divided into three groups indicating anthropogenic impact on the spring habitats. Water bug communities divided springs into four groups. There are differences in species richness between these four types of water bug assemblages and among the studied spring types. Results of CCA analysis revealed spring size as the main driver of biotic diversity of aquatic bugs in springs. Our study showed that community groups of water bugs specified in the biotic classification of spring habitats are much better defined than assemblages distinguished in the environmental site classification.

Author Correction: A global analysis of terrestrial plant litter dynamics in non-perennial waterways

In the version of this Article originally published, the affiliation for M. I. Arce was incorrect; it should have been: 5Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany. This has now been corrected in the online versions of the Article.

Comparative morphoanatomical analysis of the leaves and stems of Daphne (Thymelaeaceae) species

Abstract A study on the morphological variability and ecological differentiation among the species in the genus Daphne was carried out which included seven species from the Balkan Peninsula: Daphne mezereum, D. laureola, D. alpina, D. oleoides, D. malyana, D. cneorum and D. blagayana. In the Balkan Peninsula, the ranges of the species in this genus overlap, which does not occur anywhere else in Europe. Descriptive statistics were measured for 20 quantitative characters of the leves and stems. A comparative analysis of the morpho-anatomical adaptations of these species shows that: D. cneorum, D. malyana and D. oleoides belong to the adaptive type of xerophytes; D. alpina is a xeromesophyte; D. blagayana and D. laureola are mesoxerophytes; and D. mezereum is a mesophyte. Principal component analysis shows the largest contribution to the formation of the variability between the different species is made by characters that are related to leaf shape (leaf length, distance between the largest leaf width and the leaf top, largest width of the leaf, leaf surface area), followed by surface area of abaxial stomata, stem characters (stem cortex thickness and stem diameter) and leaf anatomy characters (thickness of the palisade tissue, thickness mesophyll, number of palisade layers). These features can use to discriminate among the seven studied species, suggesting that leaves and stems of Daphne can represent a source for taxonomically useful characters. Canonical discriminant analysis and the clustering method based on Mahalanobis distances shows that there is significant morphological differentiation among the species studied. The results show that various combinations of morphological and anatomical features contribute to the adaptive capacity of plants to different degrees. The morpho-anatomical features found in all seven species agree with previous infrageneric taxonomic classifications of this genus.