Response of Arctic Alpine Biota to Climate Change – Evidence from Polar Urals GLORIA Summits

Abstract

Polar Urals as one of target regions of Global Observation Research Initiative in Alpine Environments (GLORIA) comprises a suite of four summits, representing an elevation gradient of alpine vegetation patterns. The sampling areas cover the summits from the tops down to the 10 m contour line and are divided into eight sections. For each section, a complete list of vascular plants and herpetobiotic arthropods was collected and resurveyed. In the period from 2001 untill 2015, the species numbers steadily increased and the total surplus of vascular plants was up to 13 species on separate summit. A general decrease in the total cover of vascular plants and changes in percentage cover of the dominant species was recorded on the permanent plots; certain species of herbs decreased and certain shrub species increased. Among the dominant species of invertebrates, ground beetles and millipedes were replaced by click beetles and spiders. After 14 years the altitudinal index calculated for vascular plants gave an average upward movement of 13.6 m, that is more pronounced than in Northern and Southern Urals. The thermophilization of the alpine plant communities of Polar Urals was found equal to 9.3% of one vegetation belt. The temperature sums obtained from data loggers demonstrate the slight tendency of increase, especially for the lower summits. IntroductionThe field sites of this study are located in the Polar Urals and constitute a part of the international long-term monitoring network GLORIA (Global Observation Research Initiative in Alpine Environments). This GLORIA initiative focuses on the alpine life zone, the area above the forestline, for tracing and understanding the response of alpine ecosystems to ongoing climate change (Pauli et al. 2015). The vascular plant species occurrence was recorded first in the year 2001 on 72 mountain summits distributed across 18 study regions in Europe, with Polar Urals among them. Since then the surveys were repeated twice, in 2008 and 2015.The Urals is a unique submeridional mountain range in Eurasia, extending over 2000 km in north-south direction from the Barents Sea and Kara Sea shores at ca. 70°N to the Pre-Aral Sea sands at ca. 48°N. The mountain range crosses several zonobiomes from arctic tundra to steppe and is, accordingly, divided into five orographic regions: Polar, Subpolar, Northern, Middle and Southern Urals (Mikhailov and Olschwang 2003). From these regions, Polar Urals is situated mainly inside the North Polar Circle and is a part of the Arctic floristic region as delimited by Yurtsev (1994). Alongside with Khibiny, Putorana Plateau and other meta-arctic mountains (Makarova et al. 2013), Polar Urals is situated at the North Polar Circle and having alpine life zone in closest contact with the arctic tundra zonobiome. That is why the results of this study are of interest for both alpine and Arctic research.In contrast to meteorological and glaciological studies, long-term observations of climate change impacts on alpine ecosystems are scarce and mainly base...