Accelerated recovery of lake macroinvertebrates in the third decade since the reversal of acidification.

Chemical reversal from acidification has been progressing in European freshwaters since the late 1980s, responding to successful control of atmospheric pollution by acidifying emissions. However, biological recovery is often delayed after improvements in water composition. We studied macroinvertebrate recovery from acidification in eight glacial lakes in the Bohemian Forest (central Europe) between 1999 and 2019. The chemical composition of these lakes reflects a complex of environmental changes, dominated by a very steep decline in acid deposition and, currently, by elevated nutrient leaching following climate-induced tree dieback within their catchments. Temporal trends in species richness, abundance, species traits and community composition were evaluated with regard to water chemistry, littoral habitat properties and fish colonisation. The results showed accelerated recovery of macroinvertebrates following two decades of gradual improvement in water composition and slowly progressing biological rehabilitation. We observed a significant increase in macroinvertebrate species richness and abundance, coupled with distinct changes in community composition, the extent of changes varying between lakes, reflecting different littoral habitat properties (vegetated vs. stony) and water chemistry. Overall, the communities shifted toward more specialised (grazers, filterers, and phytophilous species) and acid-tolerant taxa at the expense of detritivorous, eurytopic and acid-resistant taxa. Where fish reappeared, open-water taxa declined greatly. Compositional changes were likely driven by the combined effects of water chemistry reversal, rehabilitation of habitat conditions and fish colonisation. Despite favourable trends, communities in recovering lakes still lack several biotic elements, particularly less vagile, acid-sensitive taxa and specialised herbivores known from the regional species pool. It is expected that future progress in lake recovery will be further promoted or inhibited by stochastic colonisation or disturbance events.

Big diversity in a small hotspot: two new species of Leptophlebiidae (Insecta, Ephemeroptera) from New Caledonia.

Two new species from Grande Terre Island, New Caledonia, namely Fasciamiruspetersorumsp. nov. and Simulacalararasp. nov. are described based on larval morphology and molecular data (COI sequences). Fasciamiruspetersorumsp. nov. is distributed in the southern part of the island and is characterised by a reduced third segment of the labial palps and all abdominal gills divided from the base. The species inhabits slow-flowing aquatic habitats with fine-grained substrate in forest brooks. Simulacalararasp. nov. is known from a single locality in the northern part of the island and is characterised by narrow and distinctly elongated abdominal gills 1-7. It was collected from fine substrates behind stones in riffles with slightly turbulent flow. Both species were recorded only in areas with ultramafic bedrock.

Climatically promoted taxonomic homogenization of macroinvertebrates in unaffected streams varies along the river continuum.

Biotic homogenization appears to be a global consequence of anthropogenic change. However, the underlying environmental factors contributing to homogenization are difficult to identify because their effects usually interact and confound each other. This can be the reason why there is very little evidence on the role of climate warming in homogenization. By analysing macroinvertebrate assemblages in 65 streams that were as close to natural conditions as possible, we avoided the confounding effects of common anthropogenic stressors. This approach resulted in revealing a significant effect of increased temperature (both summer and winter) on changes in macroinvertebrate compositional over the past two decades. However, homogenization was significant only at opposite ends of the river continuum (submontane brooks, low-altitude rivers). Surprisingly, species of native origin predominated overall, increasing in frequency and abundance ("winners"), while only a minority of species declined or disappeared ("losers"). We hypothesise that undisturbed conditions mitigate species declines and thus homogenization, and that the temperature increase has so far been beneficial to most native species. Although we may have only captured a transitional state due to extinction debt, this underscores the importance of maintaining ecological conditions in stream to prevent species loss due to climate change.

Mayfly Ephemeraglaucops (Ephemeroptera, Ephemeridae) recorded in the Czech Republic after almost a century.

Background: The mayfly Ephemera (Sinephemera) glaucops Pictet, 1843 has been considered regionally extinct in the Czech Republic, with the last occurrence dating from 1933. Its extinction was connected with the anthropogenic changes of lowland rivers, forming the original habitat of E.glaucops within the area of the Czech Republic. However, the species has been reported as spreading in man-made, often post-industrial waterbodies in Germany, The Netherlands and Austria since the 1970s. New information: We report E.glaucops from the Czech Republic, based on 27 larvae collected in the North Bohemia lignite basin in 2018. All individuals were found at one locality - a small kaolin pit in the shallow part near the shore, mostly without macrophytes. We provide details about the locality and morphological diagnostic characters of E.glaucops. This study highlights the importance of post-industrial sites for aquatic biodiversity as surrogate biotopes for degraded original habitats.

A new species of Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae) from Azerbaijan and Iran.

A new species, Epeorus (Caucasiron) hyrcanicussp. nov., is described based on larval morphology and molecular data (COI) containing sequences from all Caucasian Caucasiron species described to date. The species is distributed in the Hyrcanian forest of southeastern Azerbaijan and northwestern Iran. Based on our wide-range sampling, the new species is likely endemic to this area. The most pronounced larval morphological diagnostic characters are the coloration pattern of abdominal sterna (a pair of oblique stripes and stripe-like medio-lateral maculae) and terga (triangular medial maculae), poorly developed projection of the costal margin of gill plates III, presence of hair-like setae on the surface of abdominal terga, and relatively wide shape of gill plates VII (in natural position from ventral view). The diagnostic characters are compared to related species, and primary information to habitat is provided.

Identification guide to larvae of Caucasian Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae).

The Caucasus and adjacent areas are inhabited by fifteen species of mayflies of the genus Epeorus, subgenus Caucasiron Kluge, 1997 (Heptageniidae). This identification guide aims to facilitate an accurate species identification of their larvae and sum up all available information on their taxonomy and distribution. An identification key is provided, and the important diagnostic characters of all species are described and illustrated. The larva of E. (C.) insularis (Braasch, 1983) is described for the first time. This study enables the routine identification of Caucasiron larvae necessary for biomonitoring and hydrobiological research in the Caucasus region.

Diversity and distribution of Epeorus (Caucasiron) (Ephemeroptera, Heptageniidae) in Iran, with descriptions of three new species.

Combining morphological and molecular data in an integrative approach, three new mayfly species of Epeorus (Caucasiron) are described. These include Epeorus (Caucasiron) alborzicus Hrivniak & Sroka, sp. nov. and Epeorus (Caucasiron) shargi Hrivniak & Sroka, sp. nov. from northern Iran, and Epeorus (Caucasiron) zagrosicus Hrivniak & Sroka, sp. nov. from central Iran. They are unambiguously delimited using both distance-based and likelihood-based approaches in the analyses of barcode COI sequences. Each new species is compared with other species of the subgenus and morphological diagnostic characters are provided. Based on extensive sampling of streams throughout the country, the distribution and habitat preferences of all Caucasiron species in Iran are assessed. Altogether, there are now six species recorded, among them also E. (C.) nigripilosus Sinitshenkova, 1976 is reported for the first time in Iran. Five species are distributed in the Alborz Mts. in northern Iran, one species was found in the Zagros Mts. in central Iran.

The impact of Miocene orogeny for the diversification of Caucasian Epeorus (Caucasiron) mayflies (Ephemeroptera: Heptageniidae).

A common hypothesis for the high biodiversity of mountains is the diversification driven by orogeny creating conditions for rapid in situ speciation of resident lineages. The Caucasus is a young mountain system considered as a biodiversity hotspot; however, the origin and evolution of its diversity remain poorly understood. This study focuses on mayflies of the subgenus Caucasiron, one of the most diversified stenotopic mayflies inhabiting various types of streams throughout the Caucasus. Using the time-calibrated phylogeny based on two mitochondrial (COI, 16S) and three nuclear (EF-1α, wg, 28S) gene fragments, we tested the role of Caucasian orogeny in biogeography, diversification patterns, and altitudinal diversification of Caucasiron mayflies. We found that orogeny promoted the lineage diversification of Caucasiron in the Miocene. The highest diversification rate corresponding with the uplift of mountains was followed by a significant slowdown towards the present suggesting minor influence of Pleistocene climatic oscillations on the speciation. The Caucasiron lineages cluster into three principal clades originating in the Upper Miocene. We found a strong support that one of the three clades diversified via allopatric speciation in the Greater Caucasus isolated in the Parathetys Sea. The other two clades originating most likely outside the Greater Caucasus diversified towards high and low altitude, respectively, indicating possible role of climatic factors and/or passive uplift on their differentiation. Current high Caucasiron diversity in the Greater Caucasus is a result of in situ speciation and later immigration from adjacent mountain ranges after the Parathetys Sea retreat. Our phylogeny supported the monophyly of Rhithrogeninae, Epeorus s.l., Caucasiron, and Iron. Epeorus subgenus Ironopsis was found paraphyletic, with its European representatives more closely related to Epeorus s.str. than to Iron. Therefore, we re-arranged taxa treated within Ironopsis to comply with the phylogeny recovered herein.

New Oligoneuriidae (Insecta, Ephemeroptera) from Iran.

Two new species of the mayfly family Oligoneuriidae are described based on larval specimens recently collected in Iran. The first new species, Oligoneuriella tuberculata Godunko & Staniczek, sp. nov., can be distinguished from all its congeners by the presence of pronounced protuberances posteromedially on abdominal terga, highly reduced paracercus, large lamella of gill I, and setation on hind margin of middle and hind femora confined to their basal halves. The second species, Oligoneuriopsis villosus Bojková, Godunko, & Staniczek, sp. nov., remarkably belongs to a mostly Afrotropical genus. The new species clearly differs from all its congeners in the shape of setae on the surface of gills and terga, pattern of body colouration, and the shape of posterolateral projections of abdominal segments. Except for the species description, the generic diagnosis of Oligoneuriopsis Crass, 1947 is briefly discussed. COI barcode sequences of both new species are provided and molecular species delimitation is tested using distance-based and likelihood-based approaches, with both new species unambiguously recognised as separate lineages. The analysis of COI also corroborates the respective affinities of both new species, estimated based on morphology. The two new species of Oligoneuriidae described herein highlight the importance of the Middle East as a centre of diversity of this mayfly family within the Palaearctic.

Small-scale Variation of Testate Amoeba Assemblages: the Effect of Site Heterogeneity and Empty Shell Inclusion.

Studies on testate amoeba species distribution at small scales (i.e., single peatland sites) are rare and mostly focus on bogs or mineral-poor Sphagnum fens, leaving spatial patterns within mineral-rich fens completely unexplored. In this study, two mineral-rich fen sites of contrasting groundwater chemistry and moss layer composition were selected for the analysis of testate amoeba compositional variance within a single site. At each study site, samples from 20 randomly chosen moss-dominated plots were collected with several environmental variables being measured at each sampling spot. We also distinguished between empty shells and living individuals to evaluate the effect of empty shell inclusion on recorded species distribution. At the heterogeneous-rich Sphagnum-fen, a clear composition turnover in testate amoebae between Sphagnum-dominated and brown moss-dominated samples was closely related to water pH, temperature and redox potential. We also found notable species composition variance within the homogeneous calcareous fen, yet it was not as high as for the former site and the likely drivers of community assembly remained unidentified. The exclusion of empty shells provided more accurate data on species distribution as well as their relationship with some environmental variables, particularly moisture. Small-scale variability in species composition of communities seems to be a worthwhile aspect in testate amoeba research and should be considered in future sampling strategies along with a possible empty shell bias for more precise understanding of testate amoeba ecology and paleoecology.

Spring-fen habitat islands in a warming climate: Partitioning the effects of mesoclimate air and water temperature on aquatic and terrestrial biota.

Climate warming and associated environmental changes lead to compositional shifts and local extinctions in various ecosystems. Species closely associated with rare island-like habitats such as groundwater-dependent spring fens can be severely threatened by these changes due to a limited possibility to disperse. It is, however, largely unknown to what extent mesoclimate affects species composition in spring fens, where microclimate is buffered by groundwater supply. We assembled an original landscape-scale dataset on species composition of the most waterlogged parts of isolated temperate spring fens in the Western Carpathian Mountains along with continuously measured water temperature and hydrological, hydrochemical, and climatic conditions. We explored a set of hypotheses about the effects of mesoclimate air and local spring-water temperature on compositional variation of aquatic (macroinvertebrates), semi-terrestrial (plants) and terrestrial (land snails) components of spring-fen biota, categorized as habitat specialists and other species (i.e. matrix-derived). Water temperature did not show a high level of correlation with mesoclimate. For all components, fractions of compositional variation constrained to temperature were statistically significant and higher for habitat specialists than for other species. The importance of air temperature at the expense of water temperature and its fluctuation clearly increased with terrestriality, i.e. from aquatic macroinvertebrates via vegetation (bryophytes and vascular plants) to land snails, with January air temperature being the most important factor for land snails and plant specialists. Some calcareous-fen specialists with a clear distribution centre in temperate Europe showed a strong affinity to climatically cold sites in our study area and may hence be considered as threatened by climate warming. We conclude that prediction models solely based on air temperature may provide biased estimates of future changes in spring fen communities, because their aquatic and semiterrestrial components are largely affected by water temperature that is modified by local hydrological and landscape settings.

Initial commented checklist of Iranian mayflies, with new area records and description of Procloeon caspicum sp. n. (Insecta, Ephemeroptera, Baetidae).

An initial checklist of mayflies (Ephemeroptera) of Iran is compiled based on critical review of available literature data, complemented with new data from 38 localities of Gilan and Ardabil provinces. At present, altogether only 46 species and 25 genera are known from Iran, 18 species are reported as new to Iran in this study. Some previously published data are critically evaluated and doubtful taxa are excluded from the list. Basic analysis of the distribution and biogeography of recorded species is given. Procloeon (Pseudocentroptilum) caspicum Sroka, sp. n. is described based on mature larva and egg. Critical differential diagnostic characters distinguishing the species from related taxa are discussed in detail.

New species of the genus Oligoneuriella Ulmer, 1924 (Ephemeroptera: Oligoneuriidae) from Turkey.

Three new species of the genus Oligoneuriella Ulmer, 1924 from Turkey are described, namely Oligoneuriella magna sp. nov., Oligoneuriella paulopilosa sp. nov. and Oligoneuriella pectinata sp. nov. Differential diagnostic characters are given with regard to the previously known Oligoneuriella species. Data on the affinities, biology, and distribution of the new species are also provided. New morphological characters (setation of mouthparts and gill plates) potentially useful for the taxonomy of the genus are introduced.

Two new species of the genus Prosopistoma (Ephemeroptera: Prosopistomatidae) from Iraq and Algeria.

In addition to the three so far known species of Prosopistoma Latreille, 1833 from West Palaearctic region, P. pennigerum (Müller, 1785), P. oronti Alouf, 1977 and P. orhanelicum Dalkiran, 2009, two new species are described based on larvae. Prosopistoma helenae sp. n. has been found in Iraq (Tigris River in Mosul) and Prosopistoma alaini sp. n. in Algeria (Oued Isser, Sidi Abdelli). Critical distinguishing characters of all West-Palaearctic species of Prosopistoma are discussed in detail.

New species of mayflies (Ephemeroptera) from Cape Verde.

To date, no mayflies have been described from Cape Verde, an archipelago of volcanic islands in the Atlantic Ocean. Based on the material collected on two islands, Santo Antão and Santiago, two species of the genus Cloeon Leach, 1815 (Ephemeroptera: Baetidae) are described based on larvae and imagines. Cloeon morna sp. n., collected in Santo Antão, and C. sidadi sp. n., collected in Santiago, have 3-segmented maxillary palps and tapered labial palps of larvae. The new species can be distinguished from each other and from other West-African species of the genus mainly according to details of the lateral spines on larval abdominal segments and characteristic colourations of vitta and terga in female imagines and colours of male turbinate eyes. Affinities to the West African species of the genus are discussed.