Revision of the calcareous fen arachnofauna: habitat affinities of the fen-inhabiting spiders

Abstract

Calcareous fens are one of the most species-rich habitats of the temperate zone of the Northern Hemisphere. In spite of this species richness, however, calcareous fens are still rather poorly investigated. Consequently, the data of the fen-associated spider fauna are also largely lacking. The aim of the research was to study the spider fauna of the calcareous fens of Latvia and to draw conclusions about what kind of spider species and ecological groups typically inhabit calcareous fen habitats. Spiders were sampled in the summer months of 2010, 2011, and 2012 at nine different calcareous fens of the coastal lowland of Latvia. The spider collection was performed by pitfall traps and a sweep net. The examined material comprised 6631 adult spider individuals representing 21 families and 149 species. The main spider ecological groups that dominated in the studied calcareous fens were hygrophilous and photophilous species which largely reflect the main properties of our studied habitats, all of which were wet, open mire habitats. Nevertheless, the fen arachnofauna consisted also of spider groups which are less typical for moist, sun-exposed, and alkaline environments, like xerophilous, sciophilous, and sphagnophilous species, respectively. Finally, several spider species collected in this study have not been previously reported for the spider fauna of Latvia, and many more might still be undiscovered in these unique and poorly investigated habitats. Therefore, it is suggested that calcareous fens deserve special attention and they should definitely be investigated further.

Hymenopteran groups' role in ecological indication along the last traditionally managed meadows in Eastern Europe

“…According to our results, the numbers of Tetragnathid spider prey increased, while the numbers of Araneids decreased. The most common Araneid prey species, Mangora acalypha, seems to prefer warm, dry and sunny places (Nentwig et al 2019;Štokmane and Cera 2018). The different taxonomic groups of wild bees and cavity-nesting Hymenopterans found at our sampling sites showed differences in their habitat affinities.…”

Improved access to arachnological data for ecological research through the ARAMOB data repository, supported by Diversity Workbench and NFDI data pipelines

“…This is particularly noteworthy given that only three institutions contributed their previously immobilized data to the ARAMOB data repository. Other notable collections of similar sizes are the dataset of Hänggi et al (1995), which is not publicly accessible, and the Atlas of the European Arachnids (Arachnologische Gesellschaft 2023a) which incorporates mainly occurrence data for understanding spider distribution and is already frequently used by scientists (Narimanov et al 2021, Purgat et al 2021, Štokmane & Cera 2018, Wersebeckmann et al 2021, Wiśniewski et al 2018). Most of the atlas data were not systematically collected, posing challenges for their application in addressing ecological research questions requiring quantitatively comparable datasets.…”

Drivers for the Diversity of Mollusc Communities in Unique Calcareous Fen Habitats

“…Ongoing climate change is altering the carbon balance in fens and threatening their flora and fauna [4]. Calcareous fens support an incredibly rich and diverse range of plants and animals, including rare and endangered species and have a high conservation value on a world scale [5][6][7]. Therefore the calcareous fens with Cladium mariscus and species of the Caricion davallianae are protected under the EU Habitats Directive [8] (code of the Habitats Directive Annex I: 7210).…”