Periglacial microclimate in low-altitude scree slopes supports relict biodiversity

Abstract

Air circulation through talus slopes creates unique microclimates, with some of the most interesting being low-elevation mid-latitude scree in areas with frequent snow-free < 0°C (e.g. “black frost”) days that allow for development of year-round ice accumulations. Here, we document this phenomenon on Kamenec Hill in North Bohemia (Czech Republic) located at an altitude of 330 m above sea level, where mean annual temperatures < 0°C are maintained in a narrow strip along the slope's lower margin. This microhabitat, as well as interstitial spaces between scree blocks elsewhere on this slope, supports an important assemblage of boreal and arctic bryophytes, pteridophytes and arthropods that are disjunct from their normal ranges far to the north. This freezing scree slope represents a classic example of a palaeorefugium that significantly contributes to protection and maintenance of regional landscape biodiversity.

Keywords:

• scree
• periglacial microclimate
• habitat islands; arthropods
• palaeorefuge

Acknowledgements

This study was supported by the Biology Centre, Institute of Entomology, Academy of Sciences of the Czech Republic (project No. Z50070508), by the Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic (project No. Z60870520), and by the Czech Ministry of Education (project No. MSM-6007665801). We wish to thank our colleagues J. Hajer, M. Holec and V. Čeřovský for their enthusiastic collaboration during field work. We also appreciate the effort of taxonomists who helped us with identification of some of the collected arthropods: M. Honců (Coleoptera), P. Bezděčka (Opiliones), K. Tajovský (Diplopoda, Oniscoidea).