Community composition and cold tolerance of soil Collembola in a collapse karst doline with strong microclimate inversion

Abstract

The study compared communities of soil Collembola along the inversed microclimatic gradient of the collapse doline of the Silická ľadnica Ice Cave (Slovakia) in spring and autumn of 2005. Kruskal-Wallis ANOVA and the MannWhitney test revealed significant differences in abundance between sites and both seasons. Significantly higher abundance means and species richness were observed at most sites during the spring compared with the autumn. NMS ordination documented a clear delimitation of communities with remarkably different soil microclimates. The community pattern of the coldest section of the gradient, with low species richness and high mean abundance, was analogous to communities living in the harsh alpine and polar soils. The collapse doline with inversed microclimate hosted a high number of species (72) and a broad variety of montane forms (13), thus documenting that these karst landforms enhance local diversity of edaphic Collembola and serve as local refugia of specialized cold-tolerant species. The cold tolerance of the four abundant species at the doline cold sites, namely Ceratophysella sigillata, Tetrodontophora bielanensis, Protaphorura armata and Desoria tigrina, was tested in the laboratory using one-hour exposition survival tests. Within a temperature range from -2.4 to -7.8 • C, T. bielanensis was the most cold-sensitive species, with a lethal dose LD50 of -4.4 • C, while D. tigrina was the most cold-resistant, showing LD50 of -5.8 • C.

Extending Janzen’s hypothesis to temperate regions: A test using subterranean ecosystems

“…Five decades after its publication, Janzen's (1967) milestone contribution has been listed among the 100 most influential papers in ecology (Courchamp & Bradshaw, 2018). The mountain passes hypothesis is seminal not only in providing a mechanistic explanation for biodiversity patterns in tropical versus temperate mountain systems (Ghalambor et al, 2006;Sheldon et al, 2018), but also because it can potentially be transferred to a large variety of habitats displaying steep gradients of thermal seasonality, including soils (Bahrndorff, Loeschcke, Pertoldi, Beier, & Holmstrup, 2009;Raschmanová, Miklisová, Kováč, & Šustr, 2015), polar waters (Peck, Webb, & Bailey, 2004;Pörtner, Peck, & Somero, 2007) and deep sea (Rex et al, 1993). Yet, the ecological complexity of most ecosystems and the challenge posed by the geographic scale at which this hypothesis can be tested, have largely prevented ecologists from comprehensively testing the underlying assumptions of Janzen's hypothesis and transferring it to non-tropical settings (Gill et al, 2016;McCain, 2009;Polato et al, 2018;Scheffers et al, 2017).…”

The cold-adapted population ofFolsomia manolachei(Hexapoda, Collembola) from a glaciated karst doline of Central Europe: evidence for a cryptic species?

“…; Raschmanová et al. ). Moreover, the stepwise 0.6°C graded arrangement in our experiment allowed for the precise determination of this parameter.…”

“…Using the same method for testing the cold tolerance, a weaker tolerance was observed in several collembolan species occupying the cold and middle parts of the studied doline, such as cold‐adapted Ceratophysella sigillata (Uzel, 1891), Tetrodontophora bielanensis (Waga, 1842) and the ecologically plastic Desoria tigrina Nicolet, 1842, and Protaphorura armata (Tullberg, 1869), (Raschmanová et al. ). A comparison with previously published data on cold hardiness and extrapolation to field conditions may be problematic due to different parameters investigated (most frequently supercooling point – SCP) and diverse experimental designs (cooling and heating rates, exposure and recovery times) by different authors (e.g.…”

“…Previous studies on the diversity of Collembola in a collapsed doline of the Silick a l'adnica Ice Cave in the Slovak Karst of the Western Carpathians (Raschmanov a et al 2013(Raschmanov a et al , 2015 indicate that F. manolachei strongly prefers the coldest zone of the collapsed doline near permanent ice. We hypothesized that temperature may have a strong impact on the life history of this local population, which probably represents a cryptic ecotype, or even a cryptic species.…”

“…that has long attracted the attention of naturalists, such as Townson (1797). The zone near the floor ice (yearly air temperature~0°C) is a specific habitat characterized by thin growths of lichens and mosses on stony debris (Petr asek et al 2010;Raschmanov a et al 2013Raschmanov a et al , 2015, similar to the harsh conditions of alpine and polar tundra soils.…”