Subterranean biodiversity and depth distribution of myriapods in forested scree slopes of Central Europe

Abstract

The shallow underground of rock debris is a unique animal refuge. Nevertheless, the research of this habitat lags far behind the study of caves and soil, due to technical and time-consuming demands. Data on Myriapoda in scree habitat from eleven localities in seven different geomorphological units of the Czech and Slovak Republics were processed. Based on previous studies, as well as knowledge of cave and soil fauna, it was hypothesised that the occurrence of a varied and peculiar fauna would show a pattern of depth distribution with variations due to local specificities. From 2005–2016 (at least one year on each site), macrofauna was collected via sets of three long-term exposed subterranean traps consisting of 110 cm long perforated tube, with ten cups located in a gradient at 5–95 cm below the soil surface. In total, 14 symphylans (not identified to species level), 271 centipedes (23 spp.) and 572 millipedes (32 spp.) were sampled. The overall depth distribution of centipedes and millipedes appeared to have relatively similar pattern, with both groups being found at all depth levels. Nevertheless, this pattern depends on locations. The depth distribution trend lines are mostly in the form of an asymmetric ‘U’, with decreased abundance until the middle of the gradient, followed by increase in the deepest levels. Epigeic species were sporadically distributed along the whole depth gradient, but concentrated at the soil surface, while some subterranean species, such as the centipede Lithobius lucifugus and the millipedes Geoglomeris subterranea, Cibiniulus slovacus and Archiboreoiulus pallidus, were recorded in the deepest parts of the gradient. This characterises the debris community as a mixture of soil and subterranean species with an absence of species exclusively found in caves. The use of different fixation methods in traps had a significant and selective impact on samples; millipedes were either attracted by ethylene glycol or repelled by formaldehyde. Centipedes were also captured more frequently in ethylene glycol; however, the species composition varied in each of the fixatives. Depth distribution of myriapods was similar in both fixative solutions. Traps with these fixatives could be recommended for similar ecological studies.

Geoglomeris subterranea (Diplopoda, Glomerida, Glomeridae), the first morphologically non‐specialized semiaquatic glomerid millipede?

“…It appears that the species permanently inhabits deeper structural layers of soil and karst cave systems (Gruber, 1985; Kocourek et al, 2017a). It was also found deep in the depth gradient in a scree slope habitat (Haľková et al, 2020). This shows, in accordance with Gruber (1985) and Decker et al (2015), that the collecting method is an important factor in studying the ecology of G. subterranea .…”

“…These findings of G. subterranea in Slovakia expand the area of its known distribution, as until recently its distribution was considered strictly Western European, related to the Atlantic region. The most eastern occurrence so far published was from the Czech Republic, where the species was recorded on three occasions from subterranean traps buried in soil (Haľková et al, 2020; Riedel et al, 2009; Tajovský & Mlejnek, 2007). There are many records on the occurrence of G. subterranea in Western Europe (Blower, 1957; Bocock et al, 1973; Heath et al, 1974; Ribaut, 1954; Scheu, 1990; Sprengel, 1986; Sutton, 1969).…”

“…Data from Central and Eastern Europe published by Lang (1954) are considered doubtful due to the absence of collection material and any details on morphology and habitats (Gulička, 1986). All the recent continental findings were represented by a very small number of individuals within small areas (Haľková et al, 2020; Riedel et al, 2009; Spelda et al, 2011; Tajovský & Mlejnek, 2007; Wesener et al, 2019). Within the area of continental climate, the species is considered rare, and there are still not enough records to delimit its range (Kime, 2001).…”

Zootoxins and Domestic Animals: A European View

“…It is estimated that only 15 (0.43%) of these species are clinically important, with the majority of these from the Scolopendra species [ 54 , 55 ]. Hundreds of species have been identified in Europe, including Scolopendra species [ 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. Despite this, most reports in humans describe centipede envenomation in tropical or subtropical areas, as centipede bites appear to be less severe in Europe [ 56 ].…”

Vertical distribution of spiders (Araneae) in Central European shallow subterranean habitats

“…The cups collect animals entering the pipe through holes at different depths, allowing to study the vertical distribution of arthropods in shallow subterranean habitats. For example, this trap design has been used to study the vertical distribution of spiders in soil and fissured rock (Laška et al 2011;Růžička and Dolanský 2016), and springtails (Rendoš et al 2016;Jureková et al 2021), and myriapods (Haľková et al 2020) in forested scree slopes.…”