Spatial and temporal dynamics of invertebrates dwelling karstic mesovoid shallow substratum of Sivec National Nature Reserve (Slovakia), with emphasis on Coleoptera

Interior spaces of the forested rocky debris (MSS) represent a transition zone between the surface and deep underground spaces and a place of animal adaptation to underground life. They serve as a refuge for relict fauna as well. The study was conducted in the limestone scree slopes in Sivec National Nature Reserve (Čierna Hora Mts, Western Carpathians, elevation about 500 m a. s. l.) covered by linden-maple forest from September 2008 to November 2009. The effort was to define the vertical and seasonal aspects of invertebrates and temperature regime. Invertebrates were collected by using subterranean traps (plastic cups with 4% formaldehyde, inserted into the depths 5–95 cm through a plastic tube), which were checked monthly. Almost 26,000 specimens were trapped. Arthropods highly dominated over gastropods and earthworms. Collembola (67.61%) and Acarina (15.55%) were eudominant. Macrofauna was represented mainly by larvae of Holometabola (7.55%) and adult Diptera (5.11%) and Coleoptera (1.13%). All these groups were captured along the total depth gradient. Coleoptera were studied in more details. Among 11 Coleoptera families, Staphylinidae predominated and were captured at all levels. Rather high species diversity was found: 67 spp. excluding common epigeic fauna. Some species supposed to be subterranean, e.g., Bryaxis frivaldszkyi slovenicus, Duvalius bokori valyianus and Omalium validum. Activity of most invertebrate groups decreased significantly with depth (prevalence of surface fauna), but it was not terminated at 1 m under surface; the same was true for beetles, both in activity and diversity. Conspicuous fact is that a mass of subterranean species were traced also close to the surface (35 cm), i.e., probably it is not necessary to put the traps as deep as in this study. Seasonal climate changes affected the activity of invertebrates which was the highest at the end of spring and the lowest during winter, but it was not completely interrupted. Microclimate was characteristic without major temperature fluctuations on the surface. It was stable deeper along with increasing average annual temperature. High diversity and the occurrence of rare faunistic elements as well as specific habitats of MSS are perspective study objects and they merit care; mature design of the next studies considering the effect of season and depth of traps deposition shall do them more effective and less laborious.