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

Abstract

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.

An ecological survey of the invertebrate community at the epigean/hypogean interface

“…According to the results of the GAMM, the prevalence of external elements dropped significantly during winter. Seasonal dynamics in faunal assemblages were observed by previous authors focusing on MSS (e.g., Crouau-Roy et al 1992, Nitzu et al 2011, Rendoš et al 2012, 2016a) and on caves (e.g., Tobin et al 2013, Ferreira et al 2015, Mammola et al 2015, Bento et al 2016, Lunghi et al 2017. It is possible to argue that, over the year, at the blurry epigean/hypogean interface, there are complex exchanges involving fauna with different levels of subterranean adaptation (Prous et al 2004, Moseley 2009, Novak et al 2012, which introduce fundamental trophic resources in the subterranean habitat (Novak et al 2013) but also cause greater fluctuations in species composition over the year.…”

“…Although several species sampled at the Pugnetto hypogean complex are unique for obvious biogeographical reasons, the composition of the animal community was in general terms quite similar to that reported from other MSS sites in the Canary Islands (Pipan et al 2011), Carpathians (Nitzu et al 2010, Rendoš et al 2012, Spain Jiménez-Valverde et al 2015, France (Juberthie and Decu 2006), and Bulgaria (Langourov et al 2014). An abundance of individuals belonging to the main taxonomical groups sampled in the MSS, also aligned literature data (Borges 1993, Rendoš et al 2012).…”

“…An abundance of individuals belonging to the main taxonomical groups sampled in the MSS, also aligned literature data (Borges 1993, Rendoš et al 2012). In particular, we mostly collected arthropods, molluscs and anellids.…”

“…The dominance of epigean species in the superficial layers of the MSS has been reported by several authors (Medina and Oromí 1990, Crouau-Roy et al 1992, Borges 1993, Gers 1998, Růžička and Thaler 2002, Deltshev et al 2011, Pipan et al 2011, Nitzu et al 2010, Rendoš et al 2012, Barranco et al 2013, Langourov et al 2014, Jimenéz-Valverde et al 2015. This result suggests that our survey actually detected the superficial layers of the MSS, which are intimately connected with the epigean and the edaphic mediums, and thus more easily colonized by external elements (Mammola et al 2016).…”

“…As a matter of fact, the great majority of the published papers investigating the MSS dealt with single model taxa, and were usually strictly taxonomical (Mammola et al 2016). The focus of the MSS studies was rarely set on the whole community and/or on ecological processes (but see, e.g., Gers 1998, Nitzu et al 2010, Pipan et al 2011, Rendoš et al 2012, Langourov et al 2014, Jimenéz-Valverde et al 2015. As an example, all the studies conducted so far in Italy focused on taxonomic descriptions of new species, sampled in the MSS by means of buried pitfall traps or sight-collected after excavation (e.g.…”