Adaptation of dwarf shrubs to Arctic tundra conditions in West Svalbard

Abstract

The stability of the biota in the Arctic regions under climate change and increasing anthropogenic burdens is influenced by the adaptive potential of its representatives. This study aimed to assess the adaptive potential of dwarf shrubs (Betula nana, Vaccinium uliginosum, and Salix polaris) in the flora of West Svalbard on the basis of their morphological and anatomical features and total leaf lipid fatty acid content. All species have similar leaf anatomy characteristics: small leaves, dorsoventral structure with clear differentiation into palisade and spongy mesophyll, which ensures their growth in the Arctic. However, S. polaris is characterized by high volumes of the stomatal apparatus, an amphistomatic type of leaf, a high palisade coefficient, a large volume of mechanical leaf tissue, and a high content of unsaturated fatty acids (UFA). These features provide high functional activity, passage through all stages of ontogenesis, and a wide distribution of the species in West Svalbard. In contrast to S. polaris, B. nana and V. uliginosum are characterized by a decrease in leaf area, a decrease in the palisade coefficient, and a hypostomatic leaf type, which, combined with an increase in the diversity of “secondary” UFA, as well as the lack of generative development, may indicate a higher level pressure of extreme conditions for the species. Thus, these features may explain their limited representation in the ecotopes of West Svalbard. In contrast to B. nana and V. uliginosum, the higher adaptive potential of S. polaris ensures its greater stability in conditions of changing habitat. All studied dwarf shrub species can be used as markers for monitoring the environment in the high Arctic.