Basaltic Outcrops as Centers of Diversity for Xerothermic Plants in the Sudetes Mountains (Central Europe)

Paweł Kwiatkowski

doi:10.3390/d13040164

Abstract

Rock outcrops have promoted a high level of species diversity and provided a stable microclimate for long time periods. The present study is devoted to plant diversity of natural Quaternary outcrops of basaltic rocks. Chorological and ecological investigations were carried out at 35 such outcrops, located within five physiogeographic units of the Sudetes Mountains. The focus was on 120 xerothermic taxa of vascular plants: 62 strictly xerothermic (steppe) taxa of the Festuco valesiacae-Brometea erecti class, and 58 thermophilous taxa representing classes Trifolio medii-Geranietea sanguinei and Quercetea pubescentis. Limited geographical ranges of these plants are manifested by variable frequency of their occurrence. Species distribution is determined by natural factors, like surface area of the outcrop, the type of basaltic rock and the type of plant communities developed. Basaltic outcrops in the Sudetes meet the criterion of habitat islands (inselbergs), serve as regional centers of vascular flora, and are refugia for marginal populations of relict species.

Highlights

An important feature of different areas on Earth, in all of the geographical regions, is the spatial diversity of habitats
Xerothermic flora of the investigated basaltic outcrops comprises 120 taxa of vascular plants, 62 of which are strictly xerothermic taxa, which are typical of Euro-Asian steppe grasslands, and 58 are thermophilous species
Due to the extremely northern location of the studied objects in the Sudetes and the influence of the humid oceanic climate, the investigated outcrops differ in terms of floristic richness from the more southern basalt hills of other parts of the Czech Massif (České Sředohoří Mountains), where numerous species representing sub-continental types of geographical range occur

Summary

Introduction

An important feature of different areas on Earth, in all of the geographical regions, is the spatial diversity of habitats. The fragmentation may result in different spatial configurations of habitat patches in the landscape and different patterns of species richness, at local to continental scales [1,2,3,4,5,6,7]. Examples of natural habitat islands on land [8,9,10,11,12,13,14] are: Lakes, oxbow lakes and peatlands of different sizes—habitat islands for aquatic and marsh organisms, summit parts of high mountains isolated by deep valleys—for high mountain species, small forest complexes in the agricultural landscape—for shrub and forest species and rock outcrops (inselbergs) of a structure different from their surroundings—for rock species

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Conclusion