Dynamics of Collembola (Hexapoda) in a forested limestone scree slope, Western Carpathians, Slovakia

Abstract

A labyrinth of air-filled voids in forested scree slopes represents one of the most common types of terrestrial shallow subterranean habitats in the temperate zone, characterized by relatively strong seasonal fluctuations of temperature and the occurrence of subterranean species of invertebrates. We carried out a year-long study to define the monthly activity dynamics of Collembola communities inhabiting a depth profile (95 cm from the ground surface) of a forested limestone scree in the Western Carpathians, Slovakia. We assessed the response of species sorted into four separate ecological forms, reflecting their affinity to the subterranean environment and to temperature parameters fluctuating over the year. Of the 62 collembolan species identified, 28 were assigned to trogloxenes, 19 to subtroglophiles, 12 to eutroglophiles, and 3 to troglobionts. Fluctuations of activity/numbers during the year were observed in all four ecological forms of Collembola and at all depths. Troglobionts and eutroglophiles, associated predominantly with deeper layers of the scree slope profile, preferred the lower temperature ranges and were typical for the autumn months. Trogloxenes and subtroglophiles were active most of the year near the surface, but specifically during the spring months characterized by higher temperature ranges. The study contributes to the general knowledge of dynamics of invertebrate activity in a forested temperate zone scree slope.

A comparison of collecting methods in relation to the diversity of Collembola in scree habitats

“…It was found that some obligate cave collembolans may occupy the deeper MSS layers, such as the small Neelus koseli (Rendoš et al 2016(Rendoš et al , 2020, which in our study was captured exclusively by pitfall traps from the moist deeper layers of the upper site of the scree gully (ZB) in Zádielska tiesňava Valley, Slovenský kras Karst. In general, obligate cave invertebrates are captured by soil samples only very rarely (Raschmanová et al 2018).…”

“…In recent years, increased attention has been paid to arthropods inhabiting a peculiar underground environment, the so-called mesovoid shallow substratum (MSS) (e.g., Jiménez-Valverde et al 2015;Rendoš et al 2016Rendoš et al , 2020Nitzu et al 2018;. This aphotic habitat with relatively stable microclimate conditions is considered to be an intermediate zone between the soil surface and deep subterranean realm (e.g., caves, pits), in which both epigean and hypogean animals are represented (Gers 1998;Juberthie 2000;Mammola et al 2016;Jureková et al 2021).…”

“…Conversely, passive techniques, e.g., high-gradient extraction of soil samples, pitfall traps and their modifications, are based on digging a horizontal or vertical hole to a suitable depth and subsequent sample collection or burying the trap inside the hole (e.g., Nitzu et al 2014Nitzu et al , 2018. Many of the latter techniques provide high quantities of Collembola, with pitfall traps being the method most widely employed in studies of this group (e.g., Rendoš et al 2012Rendoš et al , 2016Rendoš et al , 2020Jureková et al 2019). Hitherto, the majority of ecological and faunistic studies carried out in MSS habitats have used only a single method for community evaluation, preferably pitfall trapping (e.g., Laška et al 2011;Jimenéz-Valverde et al 2015;Růžička and Dolanský 2016), and studies targeting a comparison of collection methods for arthropods inhabiting MSS biotopes are very rare (Gers and Cugny 1983).…”