Two rare species of swamp spiders have been added to the fauna of Slovakia
Scientists from the Institute of Landscape Ecology of the SAS, in cooperation with the West Slovak Museum in Trnava and the Czech University of Life Sciences in Prague, have documented the presence of two rare spider species previously unknown in Slovakia. These species, Larinia elegans and Tetragnatha reimoseri, are associated with wetland habitats characterized by dense coastal vegetation. Their discovery expands knowledge of the distribution of these species in Central Europe and also confirms the importance of wetlands as refuges for biodiversity.
“Wetlands are among the most endangered habitats in the world, but they are also one of the richest ecosystems in terms of biodiversity. The findings of new spider species show that even in relatively well-researched areas, targeted research can bring new and important knowledge,” says Pavol Purgat, first author of the study published in the scientific journal Check List.
Wetlands as a refuge for rare species
Both identified species are closely linked to specific wetland habitats, especially reed beds and the coastal vegetation of stagnant or slowly flowing waters. Larinia elegans is a nocturnal spider that builds its webs in reed beds, often directly above the water surface. During the day, it hides in the stems or leaves of the reeds, where it also hibernates.
Reimoser's spider (Tetragnatha reimoseri) is an extremely rare and little-known species. "It is a moisture-loving spider with a typically elongated body and a protrusion that forms a 'tail' at the end of the body, which makes it look quite unusual for a spider," says P. Purgat. It occurs on densely overgrown edges of wetlands. This species is associated with a stable, undisturbed environment with high humidity, making it a sensitive indicator of habitat preservation.
The occurrence of both species was confirmed at two locations – Rudava gravel lake in Záhorie and the National Nature Reserve Parížske močiare in southern Slovakia. These areas serve as important refuges for several specialized and rare animal species.
They were discovered at night
The scientists point out that both species have probably been overlooked in Slovakia for a long time. The reason is their secretive lifestyle, low abundance, and especially their nocturnal activity. “Traditional daytime collection methods may not be effective enough for such species. Our results clearly show that nocturnal collection is key to researching wetland spiders,” explains P. Purgat.
The research took place in several stages over several years and combined both daytime and nocturnal collection methods. It was the inclusion of nocturnal field research that enabled the capture of species that would otherwise have gone unnoticed. These findings suggest that similar wetland habitats in Slovakia may also harbor other rare or previously undiscovered spider species.
Inconspicuous inhabitants of endangered habitats
Wetlands have long been under pressure from drainage, watercourse regulation, overgrowth, and inappropriate management of reed beds. Changes in vegetation structure can have a significant impact on species that are tied to specific microhabitats. In the case of spiders, improper management or the elimination of riparian stands can lead to the loss of web-building sites or limit overwintering opportunities.
The findings of Larinia elegans and Tetragnatha reimoseri thus also point to the need for a sensitive approach to wetland management that takes into account the requirements of less conspicuous, but ecologically important, animal groups.
Small animals with great significance
“Although people are often afraid of spiders, these small animals play an irreplaceable role in nature. As predators, they regulate insect populations and help maintain ecological balance. At the same time, they are important bioindicators – their species composition and abundance can reflect the state of the environment,” Pavol Purgat adds.
The discovery of two new species of spiders in Slovakia, therefore, represents not only an expansion of the species list but also further evidence of the high natural value of wetland ecosystems. Scientists believe that continued targeted research on wetlands may bring further interesting discoveries in the future.
Prepared by: Pavol Purgat, ÚKE SAS
Photo: Pavol Purgat et al.