Local- versus broad-scale environmental drivers of continental ß-diversity patterns in subterranean spider communities across Europe.

Macroecologists seek to identify drivers of community turnover (ß-diversity) through broad spatial scales. However, the influence of local habitat features in driving broad-scale ß-diversity patterns remains largely untested, owing to the objective challenges of associating local-scale variables to continental-framed datasets. We examined the relative contribution of local- versus broad-scale drivers of continental ß-diversity patterns, using a uniquely suited dataset of cave-dwelling spider communities across Europe (35-70° latitude). Generalized dissimilarity modelling showed that geographical distance, mean annual temperature and size of the karst area in which caves occurred drove most of ß-diversity, with differential contributions of each factor according to the level of subterranean specialization. Highly specialized communities were mostly influenced by geographical distance, while less specialized communities were mostly driven by mean annual temperature. Conversely, local-scale habitat features turned out to be meaningless predictors of community change, which emphasizes the idea of caves as the human accessible fraction of the extended network of fissures that more properly represents the elective habitat of the subterranean fauna. To the extent that the effect of local features turned to be inconspicuous, caves emerge as experimental model systems in which to study broad biological patterns without the confounding effect of local habitat features.

Xerophilic Alopecosa sulzeri (Pavesi, 1873) (Araneae: Lycosidae)-a new wolf spider species in Poland.

There are 44 species and subspecies of the genus Alopecosa known in Europe, and 13 of them have so far been listed as occurring in Poland. Alopecosa sulzeri (Pavesi, 1873) is a xero- and thermophilic species distributed in the western Palearctic. In Europe, it occurs primarily in the south-east, while it is rare in Central Europe. Between 2007 and 2013, we recorded the species in the central-eastern, north-western and south-western parts of Poland. The sites of A. sulzeri in Poland are located at the northern limit of the geographic range of the species in Europe. Alopecosa sulzeri was caught at four sites in three regions, exclusively in xerothermic grasslands: in the Podlasie Bug Gorge, the Lower Oder Valley and the Trzebnickie Hills. The sites may be relict, or they may provide evidence of the spread of the species from sites located in neighbouring countries. Further spread of stenotopic, xerophilous A. sulzeri in Poland, if continued, is likely to be a slow process, due to the limited number of suitable habitats.

Continental data on cave-dwelling spider communities across Europe (Arachnida: Araneae).

BACKGROUND: Spiders (Arachnida: Araneae) are widespread in subterranean ecosystems worldwide and represent an important component of subterranean trophic webs. Yet, global-scale diversity patterns of subterranean spiders are still mostly unknown. In the frame of the CAWEB project, a European joint network of cave arachnologists, we collected data on cave-dwelling spider communities across Europe in order to explore their continental diversity patterns. Two main datasets were compiled: one listing all subterranean spider species recorded in numerous subterranean localities across Europe and another with high resolution data about the subterranean habitat in which they were collected. From these two datasets, we further generated a third dataset with individual geo-referenced occurrence records for all these species. NEW INFORMATION: Data from 475 geo-referenced subterranean localities (caves, mines and other artificial subterranean sites, interstitial habitats) are herein made available. For each subterranean locality, information about the composition of the spider community is provided, along with local geomorphological and habitat features. Altogether, these communities account for > 300 unique taxonomic entities and 2,091 unique geo-referenced occurrence records, that are made available via the Global Biodiversity Information Facility (GBIF) (Mammola and Cardoso 2019). This dataset is unique in that it covers both a large geographic extent (from 35° south to 67° north) and contains high-resolution local data on geomorphological and habitat features. Given that this kind of high-resolution data are rarely associated with broad-scale datasets used in macroecology, this dataset has high potential for helping researchers in tackling a range of biogeographical and macroecological questions, not necessarily uniquely related to arachnology or subterranean biology.

Distribution, habitat affinities and phenology of the Micrargus herbigradus-species group (Araneae: Linyphiidae) in Poland.

We review the known information on the distribution and habitat affinities of the Micrargus herbigradus-species group in Poland. The analysis is based on a thorough literature survey, our own materials, and verification of some older collections. We give new diagnostic drawings and review the characters that are useful in identification of species within the group. Three species are present in Poland: M. herbigradus (Blackwall, 1854), M. apertus (O.-P. Cambridge, 1870) and M. georgescuae Millidge, 1976. The latter is recorded for the first time in the country, and we add numerous new localities for the two former species. Micrargus herbigradus is common and widespread in Poland, living in various habitats, with only a slight preference to forests. In contrast, M. apertus is widely distributed but rarely found, while its affinity to forests is the highest within the group. The records of this species are most numerous in lowland forests (up to c. 300 m a.s.l), but it can also be found at higher altitudes. M. georgescuae is found only in montane habitats, both in the Sudetes and the Carpathian Mountains, from above 650 m a.s.l. The adults of all three species occur the whole year round, but seem to be most abundant in May and June.