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Even in a biodiversity hotspot such as the Mediterranean basin, aspects relating to the distribution of some groups of microcrustaceans still need clarification. In this paper, we critically analyse the available information on diaptomid copepods in Tunisian inland waters and, based on the largest sampling campaign to date carried out in the country, report new data on their distribution. In the frame of this study, 248 crustacean samples were collected from 190 sites, and 10 diaptomid species belonging to 7 genera and 2 subfamilies were found in the samples. Their distribution follows a climate gradient determined by precipitation, and ecological variables mainly affect diaptomid distribution in the study area, while pure spatial factors are of negligible importance. Diaptomid biodiversity is therefore strongly linked to the diversity of inland waters that characterise the country. This is especially true in the wetlands of the Medjerda alluvial plain, where six diaptomid species co-occurred sympatrically, with up to four or five species coexisting syntopically and synchronically in some sites. Unfortunately, the natural water bodies of this plain are currently strongly threatened by urban expansion and agricultural reclamation, and the risk of local extinction for the species they host is increasingly high. [ABSTRACT FROM AUTHOR]

The Niphargus tatrensis species complex, entirely subterranean, has a wide distribution range extending from Southern Poland to Austria and Slovenia. Because of its large and confusing morphological variability, it was subdivided into several 'forms', four of which described from Austrian caves. To shed light on this chaotic situation, we sampled the type localities of all described species and forms in the complex, as well as additional sites in Austria, and used nuclear (28S, ITS) and mtDNA (COI) sequences to revise its taxonomy. Phylogenetic analysis confirmed that the Niphargus tatrensis species complex is monophyletic. Applying four species delimitation methods to the COI dataset converged on the presence of four species in Austria; by contrast, the same methods applied to ITS concurred with a haploweb analysis of this marker in distinguishing only three species in the country. Reconstruction of ancestral ranges suggested that the Austrian clade originated in Eastern Europe. Bayesian biogeographical analyses revealed a complex history of lineage divergence and secondary contact during the Pleistocene climatic fluctuations, possibly responsible for the higher variability of COI in comparison with ITS. Based on the above, we conclude that only three valid species are present in Austria: considering all described forms as subspecies, two of them are elevated to species rank whereas one new species is formally described and illustrated. [ABSTRACT FROM AUTHOR]

The Classical Karst (sensu stricto) represents a complex hydro-geomorphological unit as well as one of the best-known karstic systems in the world. For this reason, it was selected as a model area both for applied research and for the conservation of its highly diverse subterranean fauna. With this paper, we aim to provide an overview of groundwater fauna in the phreatic zone of the Classical Karst aquifer, based on all published material along with new surveys, and search for patterns of species distribution within hydrogeological subunits, with a focus on the potential use of species as tracers of hydrological connections and groundwater flowpaths. The Classical Karst, with an area of approximately 750 km2, and adjacent to alluvial and flysch areas provides habitats for 83 stygobionts (accompanied by 16 stygophiles) and is one of the richest hotspots for groundwater fauna across the globe. The rate of endemism within the area is very high (around 50%). Multivariate statistical analyses revealed the faunal turnover between hydrogeological subunits, as well as the effect of water flow regime. Our approach, using species turnover and the species indicator value, allowed us to recognise groups of indicator species, which can be considered as descriptors of aquifer type and habitat structure, as well as water flow regime and groundwater flowpaths. [ABSTRACT FROM AUTHOR]

Diaptomid copepods are an important component of biodiversity in inland aquatic ecosystems worldwide but to date little is known about the historical and ecological factors that determined their current distribution. In the present paper, a critical review of the available literature on diaptomid species distribution in the Western Palearctic was performed, and a biogeographical analysis was carried out on the roles that spatial, current environmental, and historical (paleoclimatic) factors played on their actual distribution in this large area. The results show a clear pattern of colonization which is only partially overlapping what has been recently proposed for other terrestrial and aquatic taxa. Disentangling beta diversity into its turnover and nestedness components, we hypothesized a complex post-glacial pattern of recolonization of the higher latitudes, encompassing the importance of extra-Mediterranean refugia in the West (due to mountain chains which represent effective barriers for recolonization coming from the Italian and Iberian peninsulas) and a more typical pattern of post-glacial recolonization from southern refugia in the East, where mountain chains are north-south oriented and therefore less effective as barriers. [ABSTRACT FROM AUTHOR]

The influence of spatial and environmental factors in explaining the structure of large branchiopod assemblages at different spatial scales is still poorly explored. We hypothesized that the extent of actual spatial connectivity, and thus the spatial distribution of a metacommunity, may depend on the environmental conditions as represented by climatic gradients and the structural characteristics of the landscape. To test this hypothesis, the distributional patterns of 14 large branchiopod species in a set of 177 temporary water bodies repeatedly sampled across Tunisia and on its main islands were analysed. Physical, chemical, morphological and climatic characteristics of the studied water bodies were collected as well, and spatial structures were described using distance-based Moran's Eigenvector Maps. Distance-based Redundancy Analysis and variance partitioning explained more than one-half of total variation. Mantel's autocorrelograms demonstrated that species composition was spatially autocorrelated at shorter distances in the Mediterranean part of the country than in the southern, more arid part. These results suggest that both dispersal limitation and species response to spatially structured environmental gradients might be involved in determining large branchiopod distribution in Tunisia and that these patterns may greatly vary on a regional basis. [ABSTRACT FROM AUTHOR]

Yearly variation in water availability patterns has a remarkable effect in the presence of freshwater microcrustacean species. We hypothesize that, based on their different reproductive strategies, Cladocera and Copepoda may show differences in their association with ponds of different hydroperiods, i.e. in their indicator value. In order to test our hypothesis, cladoceran and copepod assemblages from ponds in Mediterranean woodlands in Latium (Italy) were analysed to evaluate their role as indicators of ponds attributed to four hydroperiod categories. Twenty-five cladocerans and sixteen copepods were collected. Correspondence analysis performed on the copepod species matrix clearly arranged the sites along a hydroperiod gradient; conversely, the same analysis carried out on cladocerans failed to distinguish between the hydroperiod categories. An indicator species analysis confirmed that copepods have a higher fidelity to the target site group. The high ability of copepods in discriminating ponds with different wet phase durations suggests their use as indicators of hydroperiod variation due to land use and climate change. [ABSTRACT FROM AUTHOR]

Microcrustacean assemblages (Cladocera and Copepoda) from astatic ponds and pools of Castelporziano Presidential Estate were analysed to evaluate their role as indicators of functional variations related to the duration of the wet phase. Samples from a subset of 23 water bodies classified as permanent or temporary (based on observations over two decades, 1989-2010) were analysed. As a whole, 36 species of microcrustaceans were present. Hierarchical clustering allowed a clear distinction between temporary and permanent water bodies. Principal coordinates analysis (PCoA) provided a good separation of the two major hydroperiod groups along the first axis, while no correlation emerged among PCoA axes and hydrogeological setting. The correlation between species and the first PCoA axis highlighted biological indicators of hydrological change: among them, the cyclopoid copepods Macrocyclops albidus and Eucyclops serrulatus, which have no resting stages, were exclusive of permanent ponds; the calanoid copepod Eudiaptomus padanus etruscus and the cladocerans Ceriodaphnia reticulata, Scapholeberis rammneri and Coronatella rectangula were present in permanent and semi-permanent ponds; the cladoceran Daphnia chevreuxi and the calanoid copepods Diaptomus serbicus, Hemidiaptomus gurneyi and Mixodiaptomus kupelwieseri were exclusive of temporary ponds with short hydroperiod (less than 6 months). Temporary water bodies hosted a higher mean species richness (13.7 species) than permanent ones (10.3), and the difference was statistically significant. Our results highlight that: (1) the cladoceran and copepod assemblage effectively discriminate between ponds with different wet phase duration, proving to be good bioindicator; (2) small astatic water bodies play an important role in biodiversity conservation, as they host a high percentage of the species distributed over wider areas, next to species which are exclusively found in these habitats; (3) hydroperiod appears to be the main driving force in characterising microcrustacean assemblages in astatic ponds. [ABSTRACT FROM AUTHOR]

Many rivers worldwide are undergoing severe man-induced alterations which are reflected also in changes of the degree of connectivity between surface waters and groundwater. Pollution, irrigation withdrawal, alteration of freshwater flows, road construction, surface water diversion, soil erosion in agriculture, deforestation and dam building have led to some irreversible species losses and severe changes in community composition of freshwater ecosystems. Taking into account the impact of damming and flow diversion on natural river discharge, the present study is aimed at (i) evaluating the effects of anthropogenic changes on groundwater/surface water interactions; (ii) analyzing the fate of nitrogenous pollutants at the floodplain scale; and (iii) describing the overall response of invertebrate assemblages to such changes. Hydrogeological, geochemical and isotopic data revealed short- and long-term changes in hydrology, allowing the assessment of the hydrogeological setting and the evaluation of potential contamination by nitrogen compounds. Water isotopes allowed distinguishing a shallow aquifer locally fed by zenithal recharge and river losses, and a deeper aquifer/aquitard system fed by surrounding carbonate aquifers. This system was found to retain ammonium and, through the shallow aquifer, release it in surface running waters via the hyporheic zone of the riverbed. All these factors influence river ecosystem health. As many environmental drivers entered in action offering a multiple-component artificial environment, a clear relationship between river flow alteration and benthic and hyporheic invertebrate diversity was not found, being species response driven by the combination of three main stressors: ammonium pollution, man-induced changes in river morphology and altered discharge regime. [ABSTRACT FROM AUTHOR]

Investigates the taxonomic characters of Diacyclops species of Copepoda in a freshwater cyclopid genus. Setation of mandibulary pulp and maxilliped; Coexistence of six congeneric species in the same sampling area; Diversity in the richness of Diacyclops species.

Describes two syntopic species of Diacyclops languidoides-group from interstitial groundwater of Lobau wetlands in Austria. Differentiating characteristics of syntopic species; Degree of specialization to the subterranean environment shown by the species.

Understanding and counteracting biodiversity losses requires quantitative knowledge on species distribution and abundance across space and time, as well as integrated and interoperable information on climate conditions and climatic changes. In this paper we developed a new biodiversity-climate database for Italy, ClimCKmap, based on the critical analysis, quality estimation and subsequent integration of the CKmap database with several high-resolution climate datasets. The original database was quality-checked for errors in toponym, species name and dating; the retained records were georeferenced and their distribution polygonised via Voronoi tessellation. We then integrated the species distribution information with several high-resolution climatic datasets: average monthly minimum and maximum temperature and total monthly precipitation were reconstructed for each Voronoi cell and year. The resulting database contains 268,977 occurrence records from 8,445 binomials and 16,332 localities, dating between 1680 and 2006 CE. This dataset, fully available at 10.6084/m9.figshare.7906739.v4 and http://hdl.handle.net/21.11125/a91f85cb-befd-4e14-8e83-24f17c4a0491, represents the largest, fully quality-checked, spatially, temporally and climatically explicit distribution database ever assembled for the Italian fauna, now ready for scientific exploitation. Measurement(s) biodiversity • climate Technology Type(s) digital curation Factor Type(s) species • geographic location Sample Characteristic - Environment key biodiversity area Sample Characteristic - Location Italy Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.9822593 [ABSTRACT FROM AUTHOR]

Subterranean ecosystems (comprising terrestrial, semi-aquatic, and aquatic components) are increasingly threatened by human activities; however, the current network of surface-protected areas is inadequate to safeguard subterranean biodiversity. Establishing protected areas for subterranean ecosystems is challenging. First, there are technical obstacles in mapping three-dimensional ecosystems with uncertain boundaries. Second, the rarity and endemism of subterranean organisms, combined with a scarcity of taxonomists, delays the accumulation of essential biodiversity knowledge. Third, establishing agreements to preserve subterranean ecosystems requires collaboration among multiple actors with often competing interests. This perspective addresses the challenges of preserving subterranean biodiversity through protected areas. Even in the face of uncertainties, we suggest it is both timely and critical to assess general criteria for subterranean biodiversity protection and implement them based on precautionary principles. To this end, we examine the current status of European protected areas and discuss solutions to improve their coverage of subterranean ecosystems., (© 2024. The Author(s).)