Search

The Postojna-Planina Cave System (PPCS) in central Slovenia is a globally exceptional site of subterranean biodiversity, comprised of many interconnected caves with cumulative passage length exceeding 34 km. Two rivers sink into the caves of the PPCS, called the Pivka and Rak, and join underground into Unica River, which emerges to the surface. The studies of fauna of PPCS began in the 19th century with the first scientific descriptions of specialized cave animals in the world, making it “the cradle of speleobiology”. Currently, the species list of PPCS contains 116 troglobiotic animal species belonging to eight phyla, confirming its status as the richest in the world. Of these, 47 species have been scientifically described from the PPCS, and more than 10 await formal taxonomic descriptions. We expect that further sampling, detailed analyses of less studied taxa, and the use of molecular methods may reveal more species. To keep the cave animals’ checklist in PPCS up-to-date, we have supplemented the printed checklist with an online interface. As the revised checklist is a necessary first step for further activities, we discuss the importance of PPCS in terms of future research and conservation.

info:eu-repo/semantics/publishedVersion

Subterranean ecosystems are among the most widespread environments on Earth, yet we still have poor knowledge of their biodiversity. To raise awareness of subterranean ecosystems, the essential services they provide, and their unique conservation challenges, 2021 and 2022 were designated International Years of Caves and Karst. As these ecosystems have traditionally been overlooked in global conservation agendas and multilateral agreements, a quantitative assessment of solution-based approaches to safeguard subterranean biota and associated habitats is timely. This assessment allows researchers and practitioners to understand the progress made and research needs in subterranean ecology and management. We conducted a systematic review of peer-reviewed and grey literature focused on subterranean ecosystems globally (terrestrial, freshwater, and saltwater systems), to quantify the available evidence-base for the effectiveness of conservation interventions. We selected 708 publications from the years 1964 to 2021 that discussed, recommended, or implemented 1,954 conservation interventions in subterranean ecosystems. We noted a steep increase in the number of studies from the 2000s while, surprisingly, the proportion of studies quantifying the impact of conservation interventions has steadily and significantly decreased in recent years. The effectiveness of 31% of conservation interventions has been tested statistically. We further highlight that 64% of the reported research occurred in the Palearctic and Nearctic biogeographic regions. Assessments of the effectiveness of conservation interventions were heavily biased towards indirect measures (monitoring and risk assessment), a limited sample of organisms (mostly arthropods and bats), and more accessible systems (terrestrial caves). Our results indicate that most conservation science in the field of subterranean biology does not apply a rigorous quantitative approach, resulting in sparse evidence for the effectiveness of interventions. This raises the important question of how to make conservation efforts more feasible to implement, cost-effective, and long-lasting. Although there is no single remedy, we propose a suite of potential solutions to focus our efforts better towards increasing statistical testing and stress the importance of standardising study reporting to facilitate metaanalytical exercises. We also provide a database summarising the available literature, which will help to build quantitative knowledge about interventions likely to yield the greatest impacts depending upon the subterranean species and habitats of interest. We view this as a starting point to shift away from the widespread tendency of recommending conservation interventions based on anecdotal and expert-based information rather than scientific evidence, without quantitatively testing their effectiveness., This study is funded by the European Commission via the Marie Sklodowska-Curie Individual Fellowships program (H2020-MSCA-IF-2019; project number 882221), awarded to S.M. Additional support is provided by the PRIN SHOWCAVE “A multidisciplinary research project to study, classify and mitigate the environmental impact in tourist caves” (project number 2017HTXT2R; funded by the Italian Ministry of Education, University and Research). M.B.M. acknowledges support from the Kone Foundation (project number 202007611). T.D., C.F., V.Z., and M.Z. were supported by the Slovenian Research Agency, through core programme P1-0184 and P6-0119. O.T.M. was supported by a grant of the Romanian Ministry of Research, Innovation and Digitization, CNCS/CCCDI— UEFISCDI, project number 2/2019 (DARKFOOD), within PNCDI III. S.I.S. acknowledges funding by MEMOBIC (EU Operational Programme Research, Development and Education No. CZ.02.2.69/0.0/ 0.0/16_027/0008357), and by the Ministry of Education, Youth and Sports of the Czech Republic (grant number CZ.02.1.01/0.0/0.0/16 025/0007417). E.P. is supported by the PON “Research and Innovation” Programme (Axis IV “Education and Research for recovery” – Action IV.6 “Research contracts on Green themes”).

Predator–prey interactions are among the most important biotic interactions shaping ecological communities and driving the evolution of defensive traits. These interactions and their effects on species received little attention in extreme and remote environments, where possibilities for direct observations and experimental manipulation of the animals are limited. In this paper, we study such type of environment, namely caves of the Dinarides (Europe), combining spatial and phylogenetic methods. We focused on several species of Niphargus amphipods living in phreatic lakes, as some of them use the dorsal spines as putative morphological defensive traits. We predicted that these spines represent a defense strategy against the olm (Proteus anguinus), a top predator species in the subterranean waters. We tested for spatial overlap of the olm and Niphargus species and showed that spined species live in closer proximity to and co-occur more frequently with the olm than non-spined species. Modeling of the evolution of the spines onto Niphargus phylogeny implies coevolution of this trait in the presence of olm. We conclude that these spines likely evolved as defensive traits in a predator–prey arms race. Combining multiple analyses, we provide an example for a methodological framework to assess predator–prey interactions when in-situ or laboratory observations are not possible.

Sex allocation theory predicts that the proportion of daughters to sons will evolve in response to ecological conditions that determine the costs and benefits of producing each sex. All else being equal, the adult sex ratio (ASR) should also vary with ecological conditions. Many studies of subterranean species reported female-biased ASR, but no systematic study has yet been conducted. We test the hypothesis that the ASR becomes more female-biased with increased isolation from the surface. We compiled a data set of ASRs of 35 species in the subterranean amphipod Niphargus, each living in one of three distinct habitats (surface-subterranean boundary, cave streams, phreatic lakes) representing an environmental gradient of increased isolation underground. The ASR was female-biased in 27 of 35 species; the bias was statistically significant in 12 species. We found a significant difference in the ASR among habitats after correction for phylogeny. It is most weakly female-biased at the surface-subterranean boundary and most strongly female-biased in phreatic lakes. Additional modelling suggests that the ASR has evolved towards a single value for both surface-subterranean boundary and cave stream-dwelling species, and another value for 9 of 11 phreatic lake dwellers. We suggest that a history of inbreeding in subterranean populations might lower inbreeding depression such that kin selection favours mating with siblings. This could select for a female-biased offspring sex ratio due to local mate competition among brothers. The observed patterns in sex ratios in subterranean species make them a group worthy of more attention from those interested in sex allocation theory.

One of the most striking features of obligate subterranean species is their narrow distribution ranges. These prevail not only at specific, but often also at generic level. However, some subterranean genera have continental scale and disjunct distribu- tion, which challenges their monophyly and questions the scenarios of their origin and colonization. In our study, we investigated the subterranean collembolan genus Verhoeffiella, currently known from five remote karst regions of Europe. Four nu- clear and one mitochondrial genes were assembled to reveal the evolutionary his- tory of the genus. We tested the monophyly of the genus, explored its relationship with putative surface relatives, and its temporal patterns of molecular diversification. The phylogeny revealed a complex relationship of Verhoeffiella with surface species Heteromurus nitidus and partially disentangled the biogeographical question of its disjunct distribution. Further on, several lineages of Verhoeffiella were recognized in the Dinarides, showing highly underestimated diversity and, compared with the number of described species, a sevenfold increase in the number of MOTUs. The radiation is relatively recent, with the events triggering the diversification linked to the Messinian salinity crisis and Pleistocene climatic shifts. The combination of this extensive subterranean radiation and close evolutionary links with epigean relatives makes Verhoeffiella an exceptional case within the subterranean fauna of temperate areas, which significantly contributes to our understanding of subterranean coloniza- tion and diversification patterns.

Species that successfully colonized subterranean environments are subject to two opposing selection processes. Stringent abiotic factors select for convergent adaptations, such as loss of eyes and pigments, while interspecific competition drives between-species divergence. Subterranean species can resolve opposing selection by adaptation to physically different microhabitats. Yet, species frequently co-occur in physically homogeneous subterranean habitats, like interstitial. These co-occurrences in such a narrow ecological context can be explained either by equalizing mechanisms, in which neither of the co-occurring species has a competitive advantage, or by more complex niche models that include species’ differentiation along a trophic niche axis. We tested these hypotheses using the amphipod genus Niphargus. We analysed Europe-wide co-occurrence records of Niphargus species from interstitial habitats, split into six independent large-scale regions. Firstly, we addressed whether species’ pairwise co-occurrences are random using a probabilistic model. Secondly, we tested whether species cluster into distinct functional–morphological groups and whether ecologically or phylogenetically distinct species are more likely to co-occur. We found that 68% of species co-occurrences were not different from random expectation, indicating that most species had access to most sites within each region. The remaining 32% co-occurred either significantly more or less often than expected by chance. Cluster analysis of functional morphological characters showed that interstitial species belong to two feeding types, micro- and macrofeeders, likely representing two peaks of the interstitial adaptive landscape, and hinting that niche divergence, as a mechanism allowing coexistence, is favoured. Finally, we found that the number of co-occurrences increases with increasing differentiation of functional morphology, but not phylogenetic differences. We conclude that ecological differentiation may be important in shaping such interstitial communities.

We Review How Different Bat Guilds Respond To Artificial Light At Night (Alan) And Assess How The Impacts Can Vary According To Ecological Context. All Studied European Species Respond Negatively To Alan Close To Roosts And Drinking Sites, And The Impacts Occur Across A Wide Range Of Light Colors And Intensities. Most Bat Species Are Sensitive To Alan When Commuting And Foraging. Although Narrow-Space-Foraging Bat Species Consistently Avoid Alan When Foraging, Open And Edge-Space-Foraging Species May Exploit Insects Lured By Alan. Therefore, Alan Acts As An Environmental Filter On Bat Assemblages. Considering The Detrimental Effect Of Alan On Insects, We Conclude That Alan Probably Has Negative Impacts On All Bat Species, Even On Those Foraging At Streetlights. The Sprawl Of Alan May Be A Key Factor Driving The Decline Of Bat Diversity Globally, And The Current Trajectory Of Increasing Alan Is Therefore Of Considerable Concern For Bat Conservation.

Five decades ago, a landmark paper in Science titled The Cave Environment heralded caves as ideal natural experimental laboratories in which to develop and address general questions in geology, ecology, biogeography, and evolutionary biology. Although the 'caves as laboratory' paradigm has since been advocated by subterranean biologists, there are few examples of studies that successfully translated their results into general principles. The contemporary era of big data, modelling tools, and revolutionary advances in genetics and (meta)genomics provides an opportunity to revisit unresolved questions and challenges, as well as examine promising new avenues of research in subterranean biology. Accordingly, we have developed a roadmap to guide future research endeavours in subterranean biology by adapting a well-established methodology of 'horizon scanning' to identify the highest priority research questions across six subject areas. Based on the expert opinion of 30 scientists from around the globe with complementary expertise and of different academic ages, we assembled an initial list of 258 fundamental questions concentrating on macroecology and microbial ecology, adaptation, evolution, and conservation. Subsequently, through online surveys, 130 subterranean biologists with various backgrounds assisted us in reducing our list to 50 top-priority questions. These research questions are broad in scope and ready to be addressed in the next decade. We believe this exercise will stimulate research towards a deeper understanding of subterranean biology and foster hypothesis-driven studies likely to resonate broadly from the traditional boundaries of this field. S.M acknowledge support by the CAWEB project “Testing macroecological theory using simplified systems”, funded by the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 882221). I.R.A. was supported by Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., under the Norma Transitória – DL57/2016/ CP1375/CT0003. D.E. was supported by IFREMER and by the CERES “Climate change and European Aquatic Resources” project funded by European Commission through Horizon 2020 research and innovation programme (Grant no. 678193). C.F., Z.F., and M.Z. were supported by the Slovenian Research Agency (program P1-0184, project N1-0069). J.E.K. was funded by NSF awards DEB1754231 and IOS1933428, and EDGE award 1923372. F.M. was supported by the French National Research Agency projects CONVERGENOMICS (ANR-15-CE32-0005) and EUR H2O’Lyon (ANR-17-EURE-0018). A.M. was supported by the ANCAVE project “Anchialine caves to understand evolutionary processes”, funded by the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 745530). P.A.V.B. was supported by the project AZORESBIOPORTAL – PORBIOTA (ACORES-01-0145-FEDER-000072), financed by FEDER in 85% and by Azorean Public funds by 15% through Operational Program Azores 2020. A.S.P.S.R. was supported by VILLUM FONDEN (Grant no. 15471) and by a Carlsbergfondet grant (CF19-0609). T.G.P. was supported by Vale S.A. and Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) for individual fellowship (RDP 00092-18). T.P. was supported by the Karst Research Programme P6-0119, LifeWatch ERIC, RI-SI LifeWatch, and EU H2020 project eLTER. info:eu-repo/semantics/publishedVersion

Ecologists increasingly rely on molecular delimitation methods (MMs) to identify species boundaries, thereby potentially increasing the number of putative species because of the presence of morphologically cryptic species. It has been argued that cryptic species could challenge our understanding of what determine large-scale biodiversity patterns which have traditionally been documented from morphology alone. Here, we used morphology and three MMs to derive four different sets of putative species among the European groundwater crustaceans. Then, we used regression models to compare the relative importance of spatial heterogeneity, productivity and historical climates, in shaping species richness and range size patterns across sets of putative species. We tested three predictions. First, MMs would yield many more putative species than morphology because groundwater is a constraining environment allowing little morphological changes. Second, for species richness, MMs would increase the importance of spatial heterogeneity because cryptic species are more likely along physical barriers separating ecologically similar regions than along resource gradients promoting ecologically-based divergent selection. Third, for range size, MMs would increase the importance of historical climates because of reduced and asymmetrical fragmentation of large morphological species ranges at northern latitudes. MMs yielded twice more putative species than morphology and decreased by 10-fold the average species range size. Yet, MMs strengthened the mid-latitude ridge of high species richness and the Rapoport effect of increasing range size at higher latitudes. Species richness predictors did not vary between morphology and MMs but the latter increased the proportion of variance in range size explained by historical climates. These findings demonstrate that our knowledge of groundwater biodiversity determinants is robust to overlooked cryptic species because the latter are homogeneously distributed along environmental gradients. Yet, our findings call for incorporating multiple species delimitation methods into the analysis of large-scale biodiversity patterns across a range of taxa and ecosystems., SCOPUS: ar.j, info:eu-repo/semantics/published

AimThere is increasing evidence showing that species within various taxonomic groups have reticulate evolutionary histories with several cases of introgression events. Investigating the phylogeography of species complexes can provide insight about the introgressions, when and where these hybridizations occurred. In this study, we investigate the biogeography of a widely distributed Western Palaearctic bat species complex, namelyMyotis nattererisensu lato. This complex exhibits high genetic diversity and in its western distribution range is composed of deeply diverged genetical lineages. However, little is known about the genetic structure of the eastern populations. We also infer the conservation and taxonomical implications of the identified genetic divergences.LocationWestern PalaearcticMethodsWe analyzed 175 specimens collected from 67 locations and sequenced one mitochondrial and four nuclear DNA markers, and combined these with the available Gen-Bank sequences. We used haplotype networks, PCA, t-SNE, and Bayesian clustering algorithms to investigate the population structure and Bayesian trees to infer the phylogenetic relationship of the lineages.Main conclusionsWe identified deeply divergent genetical lineages. In some cases, nuclear and mitochondrial markers were discordant, which we interpret are caused by hybridization between lineages. We identified three such introgression events. Our findings suggest that the M.natterericomplex has a reticulate evolutionary history with multiple cases of hybridizations between some of the identified lineages. We also suggest a revision in the taxonomy of this species group, with two possible new taxa:M. hoveliandM. tschuliensis.

In light of recent alarming trends in human population growth, climate change, and other environmental modifications, a “Warning to humanity” manifesto was published in BioScience in 2017. This call reiterated most of the ideas originally expressed by the Union of Concerned Scientists in 1992, including the fear that we are “pushing Earth's ecosystems beyond their capacities to support the web of life.” As subterranean biologists, we take this opportunity to emphasize the global importance and the conservation challenges associated with subterranean ecosystems. They likely represent the most widespread nonmarine environments on Earth, but specialized subterranean organisms remain among the least documented and studied. Largely overlooked in conservation policies, subterranean habitats play a critical role in the function of the web of life and provide important ecosystem services. We highlight the main threats to subterranean ecosystems and propose a set of effective actions to protect this globally important natural heritage.

The ability to describe and explain the spatial distribution of subterranean fauna is becoming increasingly more important as man continues to expand his reach and encroaches on traditionally inaccessible areas. To that end, it is important to understand the processes that have led to and sustain such distributions, and in the light of recent environmental changes, to help in understanding the impact of future environmental scenarios. Hence, an increasingly urgent need is the ability to accurately map the geographic distribution of various species and ecosystems (and often as critical, the distribution of the required habitat). Mapping includes not only the graphical presentation of species occurrences and derived parameters such as densities and species richness over a region but, more importantly, it includes the statistical spatial modeling that provides both the map and the means of assessing its accuracy. Here we present some statistical approaches that provide such information that can be used in interpretation, hypothesis testing, and decision-making. The methods include a general introduction to geostatistical models as well as spatial autoregressive models for data collected or aggregated to nonoverlapping regions as is common for diversity studies of cave fauna.

We tested three hypotheses (productive energy, habitat heterogeneity, historical climate stability) to explain regional species richness patterns in subterranean habitats, which have less habitat/climatic variability than surface habitats. For the first time, we investigated the pattern of two species richness hotspots in the world's richest region in subterranean biodiversity in southeast Europe. We used distribution records for 388 species of beetles, the most species rich group of terrestrial subterranean fauna, belonging to subfamilies Trechinae (Carabidae) and Leptodirinae (Cholevidae), and mapped them onto a 20 × 20 km grid. We applied spatial and non-spatial multiple regression, using generalised linear models and spatial eigenvector mapping. The relative importance of each hypothesis, and of the spatial versus the environmental components, was assessed with variation partitioning. We analysed the total dataset as well as each subfamily separately. Our results show that although the relative importance of species richness drivers differed among taxonomic groups, in most cases habitat heterogeneity had the biggest influence. It was followed by historical climate stability, while productive energy had a neglecting effect. This proves that even though habitat variability is smaller in subterranean than in surface habitats, its gradient is still strong enough to explain species richness patterns better than the other two hypotheses. Identification of the drivers shaping the two regional species richness hotspots within a global hotspot of highly endemic subterranean fauna is important for conservation practices. Additionally, we contribute to the general understanding of species richness patterns of insects, by providing the first detailed analyses on a regional scale for subterranean systems.

Species richness patterns (SRP) emerge due to overlap in species distributions. They critically depend on two parameters of species ranges: geographic position and size. An important question is which species contribute more to the observed SRP, range restricted or widespread species. Most studies concluded that the widespread species tend to influence SRP more. However, the relative importance of either may strongly depend on the study system. Here we investigated how subterranean species of different range sizes contribute to SRP in the Western Balkans. We studied spatially defined datasets of terrestrial and aquatic troglobionts, represented by beetles (Cholevidae, Carabidae, 425 species) and amphipod crustaceans (Niphargidae, 150 species), respectively. The two groups differ in dispersal capacities, and indeed distribution of their range sizes differed. The proportion of single site species reached 30% in beetles, and 21% in niphargids. Maximum linear extent (MLE) of the range exceeded 200 km in only 1% of beetles, but in nearly 20% of niphargids. SRP of both taxonomic groups only partly overlapped. To assess the contribution of species with different ranges on SRP, we created different subsets and compared their SRPs with full dataset SRP. Subsets were first formed by adding species one-by-one, in ascending and descending order according to range size. We used correlation analysis, with significance assessed using null models generated from randomly generated subsets. In the second analysis, we assigned species info four classes according to range size, and modelled which size class best explains SRP. The results showed certain differences among the two taxonomic groups, which make generalizations difficult. We find it important to evaluate the contribution of species with different ranges to overall SRP, but also to identification of local hotspots.

Decades of debates around the species problem have resulted in the emergence of a unified species concept with multiple criteria to delimit species taxa. Many biologists now agree to consider species as separately evolving segments of metapopulation lineages (i.e. the species concept), and to consider species taxa (i.e. the elementary units used in biodiversity science) as scientific hypotheses of separately evolving entities. In this framework, sets of species hypotheses are generated using different criteria (i.e. morphological distinguishability, genetic isolation) that mirror the properties expressed by species at different times and sequential orders during the extended and heterogeneous process of speciation. This conceptual and methodological advance in taxonomy has several implications for biodiversity science. First, species taxa represent a heterogeneous set of hypotheses whose properties are contingent on the heterogeneous, continuous and extended nature of speciation. Second, species databases need to integrate information on the diverse properties of species by attributing specimens to multiple species hypotheses generated using different delimitation criteria. Third, biodiversity science at large can provide novel insights into biodiversity processes by incorporating multiple species hypotheses into the analysis of biodiversity patterns. Here, we show how these implications have been taken into account by subterranean biologists. First, we briefly review the criteria and methods used to delimit species in subterranean biology and the diverse sets of species hypotheses they generated. Second, we present a new generation of species occurrence databases that integrate different species criteria and hypotheses while fully respecting the scientific rigor of taxonomy. Last, we show how incorporating multiple species hypotheses into macroecological analyses of European groundwater fauna bolsters our under­standing of the factors shaping large-scale patterns of species richness and geographic range size.

The family Moitessieriidae includes minute dioecious gastropods exclusively inhabiting subterranean waters, including thermal ones. Only empty shells were collected in most species, the vast majority of them are described from their gross shell morphology alone. Several visits to a site are usually required to obtain at least some living individuals. High variability in shell morphology and the lack of diagnostic features, coupled with anticipated high levels of endemism, has resulted in a long list of nominal moitessierid species. Type specimens stored as empty shells omit unambiguous identification and delimitation of species boundaries. Due to inaccessibility of cave animals and consequent lack of material suitable for molecular analysis, the phylogenetic relationships, as well as the taxonomy of the family at genus/species level, are far from being understood. The anatomy of the family is also poorly known and provided only for a few taxa. The distinctness of the Moitessieriidae has sometimes been questioned, and their monophyly not proved. Twelve species of the Balkan Moitessieriidae are considered: two species of Paladilhiopsis, two species of Bythiospeum, six species of Iglica, Costellina turrita and Lanzaia bosnica. The shell morphology of each species, as well as the reproductive system of Paladilhiopsis and Iglica, were analysed. DNA sequences of nuclear histone H3, ribosomal 18S, ribosomal 28S and mitochondrial cytochrome oxidase subunit I (COI) were applied to infer phylogenetic relationships among the taxa. The sequences of Bythiospeum from GenBank have been used to infer relationships between Bythiospeum and Paladilhiopsis that were recently synonymized. Paladilhiopsis and Iglica are distinct, but closely related genera, as is the genus Bythiospeum, which does not occur in the Balkans. Its relationships with both former taxa remain unresolved. The Moitessieriidae are clearly distinct from all other families of the Truncatelloidea, however, their monophyly remains doubtful.

Niphargidae is among the largest families of freshwater subterranean amphipods in the world, and one of the most important macroinvertebrate groups in European groundwaters. The knowledge of their species diversity on a country level is often incomplete due to demanding taxonomy. In this paper we critically evaluated species diversity of the family in Belgium, using published records and samples from our own field work. Morphology-based identifications confirmed the presence of genera Microniphargus and Niphargus, represented with one and eight species, respectively. Most of the species found in Belgium belonged to complexes of cryptic species, which are still awaiting their taxonomic epilogue. Four species belong to phylogenetic lineages distributed also across British Isles, whereas three species belong to lineages distributed in the west-continental Europe. Identity of one species was doubtful, and two populations, partially illustrated herein, showed distinct morphology and might belong to a new species. All together, Niphargidae were found at 172 localities, with 80% of sites harboring one species only. At 12 localities three to six species co-occurred. When mapped onto 10x10 km grid, up to seven different species were recorded per quadrate. Species richest quadrates were situated in the southeastern part of the country. Paucity of records from the northern part of the country imply lack of research, rather than absence of Niphargidae. Conservation status of Belgian Niphargidae has not been evaluated so far; assessment of this status would require further sampling and detailed taxonomic work.

Due to increasing human activities with negative impacts on wildlife and natural habitats, it has become necessary to establish conservation policies protecting at least parts of natural diversity. Subterranean fauna presents a challenge for conservation as species with small ranges or single site occurrences are common. In addition to the high level of strict endemism, the concealed lifestyles in habitats that are difficult to access make it challenging to establish the conservation status of subterranean species. Conservation approaches have different practical implications, but they should: i) include a sufficient number of important sites or proportion of species populations, and ii) involve monitoring of target species and habitats to check the effectiveness of conservation efforts. We evaluated both aspects in two study cases on subterranean fauna from Slovenia, which is known as one of the global biodiversity hotspots in the Western Balkans. In the first case, we investigated to what extent current conservation schemes cover single site species. In the second case, we studied a region in Southern Slovenia and evaluated to what extent the EU legislation, namely EU Habitats directive, has been successfully implemented. In the frame of the latter, Sites of Community Importance were designated also due to the presence of important cave habitats and subterranean species. Our results suggest that the inclusion of important subterranean sites in conservation schemes is considerable. But, the apparent lack of research and monitoring of both subterranean habitats and species hampers the conclusions on effectiveness of different conservation approaches.

By offsetting the discipline of speleobiology with the discovery of the first subterranean beetle Leptodirus hochenwartii, Slovenia became the country with the longest tradition of speleobiological research. Subterranean beetles have been an undepletable study subject for almost two centuries, giving the impression that not much novelty is expected in beetle fauna. However, recent discoveries of two new beetle genera for Slovenia, one of them even being a new genus for science, have put this view into a new perspective. With the development of caving techniques and growing interest for surveying deep vertical caves, also the intensity of speleobiological studies of these caves gradually increased. So, it was only in 2017, that the first specialized, hygropetric beetle, was found in Slovenia. In Southern part of the country, a sole female specimen from genus Croatodirus (fam. Leiodidae), probably belonging to a new species, was collected from a cave in Mt. Snežnik, at depth of 475 m. Second, in the same year, even more spectacular finding came from the Southern Calcareous Alps. During sampling of a cave on Mt. Raduha, a peculiar and highly troglomorphic Trechinae (fam. Carabidae) was found at depth 450 m, near the cave hygropetric. Thorough morphological examination of a single male collected revealed characters similar to the ones known in the Southern Dinaric Scotoplanetes - genus known to inhabit the cave hygropetric. However, when the newly discovered genus was put into Alpine Trechinae phylogenetic framework, its sister relation with a narrow-endemic genus Aphaenopidius was revealed. Such rare and occasional findings raise questions regarding the completeness of our knowledge on alpha taxonomy and the mechanisms underlying convergent evolution in the subterranean realm. Poster: Suppl. material 1

In the last two decades, there has been a substantial progress in the availability of records for several subterranean taxa, as well as in mapping and statistical modeling of biodiversity patterns. Currently, there is still a large bias toward analyses of aquatic compared to terrestrial subterranean taxa. We provide the first global map of species richness for groundwater crustaceans, indicating that tropics are not hotspots of species richness. Detailed analyses of subterranean biodiversity patterns in Europe show that species richness peaks in regions of mid-latitude, where the beneficial effects of a high productive energy and high habitat heterogeneity have not been counteracted by cold or arid historical events. The range size of European groundwater crustacean species increases northward, a pattern which is best explained by long-term climatic changes. Subterranean species have narrow distribution ranges, which results in a high spatial turnover in species composition across regions and a disproportionally high contribution of regional diversity to total species richness. Within regions, biodiversity patterns are diverse, and their explanations vary across regions, but hotspots contribute only a small proportion of the regional species pool. Molecular approaches to biodiversity studies offer promising research avenues for further documenting and understanding subterranean biodiversity patterns.

Aim Three broad mechanisms have been proposed to explain geographic variation in species range size: habitat area/heterogeneity, climate seasonality and long-term climate variability. However, it has proved difficult to disentangle their relative role, particularly as temperature seasonality often covaries with the amplitude of long-term temperature oscillations. Here, we shed new light onto this debate by providing the first continental-scale analysis of range size and beta diversity in groundwater habitats, where taxa are not exposed to latitudinal variation in temperature seasonality. Location Europe. Methods We compiled and mapped occurrence data for 1570 groundwater crustacean species. Generalized regression models were used to test for latitudinal variation in geographic range size and to assess the relative role of the three broad mechanisms in shaping present-day patterns of range size. We partitioned beta diversity into its spatial turnover and nestedness components and analysed their latitudinal variation across Europe. Results Median range size increases with latitude above 43° N and the range size of individual species is positively correlated to latitude, even after accounting for phylogenetic effects. Long-term temperature variability accounted for a substantially higher variation in median range size of groundwater crustaceans across Europe than precipitation seasonality and habitat heterogeneity, including aquifer area, elevation range, climatic rarity and productive energy. Spatial turnover contributes significantly more to beta diversity in southern regions characterized by stable historic climates than it does in northern Europe. Main conclusions Our findings add support to the historic climate hypothesis which suggests that patterns of increasing range size and decreasing species turnover at higher latitudes in the Palaearctic region are primarily driven by long-term temperature oscillations rather than by climatic seasonality and the availability and heterogeneity of habitats.

The known diversity of freshwater amphipods in South America is substantially lower than on other continents. This has puzzled biologists for decades. Two hypotheses have been proposed in attempts to explain this pattern. According to the first one, the majority of amphipod lineages never dispersed across South America. The alternative hypothesis is that the recently diversified hyalellids have outcompeted and depleted the ancestral amphipod fauna. The recently discovered freshwater amphipod species Seborgia potiguar sp. nov. (Seborgidae) and Potiberaba porakuara gen. nov., sp. nov. (Mesogammaridae) from Brazil reveals the existence of two additional families of amphipods in South America. In the light of these discoveries we have analysed the amphipod faunistic structure of South America to test the above two biogeographic hypotheses. First, the number of amphipod families in South America is not as low as was thought. Falklandellididae are limited to the Falkland Islands and Chile. All other families (I...

A series of potential pitfalls (fallacies) in estimating subterranean biodiversity are outlined: (1) provincialism—treating different regions differently, especially with respect to new discoveries and undescribed species; (2) equality of described and undescribed species—ignoring the possibility that undescribed species are not really new species; (3) isotropy—assuming all cave regions of similar size have equally rich faunas; (4) scale invariance—ignoring the affect of area on species richness; and (5) misuse of expert opinion—the over-reliance on experts estimates often without comparable estimates for all areas. Some standard procedures are suggested for subterranean biodiversity studies, and the value of such studies is emphasized.

The first record of the palpigrade Eukoenenia gasparoi Conde 1988 in Croatia is reported. We review the distribution of this troglobiotic species endemic to the classical European Karst region, give an illustrated description of the adult stages and the juvenile female, and evaluate divergence among the populations. Morphological differences reflect individual-level rather than population-level variation.

Subterranean species show a distinct morphology, yet the adaptive significance of some traits, like body size and shape, is poorly understood and cannot be explained solely by distinct environmental conditions (darkness, less food). We predicted that in females some morphological changes may have co-evolved with life history traits, and that co-evolving life history traits provide at least part of the explanation for evolutionary changes of morphology. Using museum material we tested this prediction on the subterranean amphipod genus Niphargus. We studied six species found in springs and eight species found in cave lakes. We treated them as two ecologically distinct groups, and the major ecological differences between them were the availability of nutrients and the water currents. Cave species were found to be larger and stouter (as inferred from the shape of coxal plates, which are part of the marsupium), they had larger eggs and lower reproductive effort per brood, whereas the egg number and brood volume if corrected for the body size were not different. Using phylogenetic independent contrasts, we found a positive correlation between body shape and egg volume, a positive correlation between body size and egg volume, and a negative correlation between body size and reproductive effort per brood. We tentatively conclude that evolutions of morphology and life histories are functionally connected and that co-evolving traits contribute to overall selective regime.

SUMMARYObligatory cave species exhibit dramatic trait modifications such as eye reduction, loss of pigmentation and an increase in touch receptors. As molecular studies of cave adaptation have largely concentrated on vertebrate models, it is not yet possible to probe for genetic universalities underlying cave adaptation. We have therefore begun to study the strongly cave-adapted small carrion beetle Ptomaphagus hirtus. For over 100 years, this flightless signature inhabitant of Mammoth Cave, the world's largest known cave system, has been considered blind despite the presence of residual lens structures. By deep sequencing of the adult head transcriptome, we discovered the transcripts of all core members of the phototransduction protein machinery. Combined with the absence of transcripts of select structural photoreceptor and eye pigmentation genes, these data suggest a reduced but functional visual system in P. hirtus. This conclusion was corroborated by a negative phototactic response of P. hirtus in light/dark choice tests. We further detected the expression of the complete circadian clock gene network in P. hirtus, raising the possibility of a role of light sensation in the regulation of oscillating processes. We speculate that P. hirtus is representative of a large number of animal species with highly reduced but persisting visual capacities in the twilight zone of the subterranean realm. These can now be studied on a broad comparative scale given the efficiency of transcript discovery by next-generation sequencing.

We investigated the pattern of species richness of obligate subterranean (troglobiotic) beetles in caves in the northwestern Balkans, given unequal and biased sampling. On the regional scale, we modeled the relationship between species numbers and sampling intensity using an asymptotic Clench (Michaelis-Menten) function. On the local scale, we calculated Chao 2 species richness estimates for 20 9 20 km grid cells, and investigated the distribution of uniques, species found in only one cave within the grid cell. Cells having high positive residuals, those with above average species richness than expected according to the Clench function, can be considered true hotspots. They were nearly identical to the observed areas of highest species richness. As sampling intensity in a grid cell increases the expected number of uniques decreases for any fixed number of species in the grid cell. High positive residuals show above average species richness for a certain level of sampling intensity within a cell, so further sampling has the most potential for additional species. In some cells this was supported by high numbers of uniques, also indicating insufficient sampling. Cells with low negative residuals have fewer species than

A phylogenetic review of Monolistra (Microlistra), a freshwater cavernicolous subgenus of isopod crustaceans, distributed in the north-western part of the Dinaric karst, is presented. The distribution data and an identification key are provided for known taxa. Seven species are reviewed and two new species are described: Monolistra (Microlistra) fongi sp. nov. and Monolistra (Microlistra) jalzici sp. nov. Monolistra (Microlistra) pretneri spinulosa Sket is synonymysed with the nominate subspecies because of the morphological variability in the type subspecies and the genetic uniformity of the species. Two major, geographically vicariant and morphologically different clades have been identified by molecular analysis. Low genetic differentiation within the subgenus, as well as conspicuous dorsal sculpturing of animals, indicate their apparently recent colonization of the hypogean realm. These indications are confirmed by the distribution of Microlistra species within the current river systems, rather than palaeo-hydrographically defined basins, as is the case of other subterranean aquatic groups of crustaceans, including other members of the genus Monolistra.

1. Distribution and status of medicinal leeches were re-considered in the light of the new taxonomy recognizing four Western Palaearctic species: Hirudo medicinalis, Hirudo verbana, Hirudo orientalis and Hirudo troctina. 2. Recent records and new data obtained on expeditions to Ukraine, Russia, Azerbaijan, Kazakhstan, Uzbekistan and the Western Balkans were mapped to obtain an up-to-date overview of the distribution. 3. Three hypotheses explaining the current ranges of all Hirudo species were tested. The ecological hypothesis, suggesting a strong impact of large-scale environmental factors, received the highest support, while anthropogenic influence was minimal, and no historical patterns of refugia and colonization were detected. 4. Mapped localities of all Hirudo species show extensive, belt-shaped ranges extending from east to west. H. medicinalis is distributed from Britain and southern Norway to the southern Urals and probably as far as the Altai Mountains, occupying the deciduous arboreal zone. H. verbana has been recorded from Switzerland and Italy to Turkey and Uzbekistan, which largely corresponds to the Mediterranean and sub-boreal steppe zone. H. orientalis is associated with mountainous areas in the sub-boreal eremial zone and occurs in Transcaucasian countries, Iran and Central Asia. H. troctina has been found in north-western Africa and Spain in the Mediterranean zone. 5. Based on the data gathered, and considering real and potential threats, global IUCN category Near Threatened is proposed for H. medicinalis, H. verbana, and H. orientalis, while H. troctina can only be assigned to category Data Deficient. Copyright © 2010 John Wiley & Sons, Ltd.

Natural history museum collections harbour valuable information on species. The usefulness of such data critically depends on the accurate identification of species, which has been challenged by introduction of molecular techniques into taxonomy. However, most collections may suffer from DNA degradation, due to age and/or improper preservation; hence the identification of specimens depends solely on morphological features. This study explores how and to what extent morphological data can help to solve ambiguous taxonomic cases based on selected species concepts and with the use of operational criteria in a species-hypothesis testing procedure. The studied taxon, the Niphargus tatrensis species complex, comprises freshwater subterranean amphipods, distributed across Central Europe, the taxonomic status of which was debated extensively between 1930 and 1960. Using the general species concept, character- and tree-based operational criteria reveal northern and southern diagnosable and exclusive lineages identified here as N. tatrensis Wrześniowski, 1888 and N. scopicauda sp. n., respectively. The remaining populations represent the non-exclusive N. aggtelekiensis Dudich, 1932, which occurs from the eastern Alps to Hungary. In the entire complex, altitudinal distribution is largely limited to areas above 400 m, where the mean annual temperature never exceeds 9°C. Seemingly well-defined distributional ranges of N. tatrensis and N. aggtelekiensis are fragmented in an ecological sense, which raises the question whether two of the three species recognised here actually consist of several unidentified taxa. Morphological similarity between the species, numerous polymorphic features, and the association with cool temperatures lead to a hypothesis in which fragmentation of the ancestral range occurred during post-Pleistocene climate warming, reducing gene flow across lowland populations due to niche conservatism of the ancestral species and/or to invasion of competitive species along the Danube and Drava rivers. The results are discussed regarding how old museum samples are conducive to more detailed molecular-taxonomic and conservation studies.