Monitoring of vascular plant diversity in a changing climate in the alpine zone of the Central Greater Caucasus

Authors: KHATUNA GIGAURI, MAIA AKHALKATSI, GEORGE NAKHUTSRISHVILI, OTAR ABDALADZE

Abstract: Short-term changes in plant species number, cover, frequency, and composition were studied along an altitudinal gradient crossing 4 GLORIA summits (from 2240 m to 3024 m a.s.l.) from the treeline ecotone to the subnival zone in the Central Caucasus. Large-scale (summit area) and small-scale (16 plots of 1 m^{2}/summit) patterns were monitored in 2001. Recording was repeated in 2008. During the monitoring period, the average soil temperature and growing-degree days did not significantly increase. After 7 years, a revisitation of the summit area revealed a considerable increase of species richness, especially at the lower alpine zone (CP1 and CP2 summits). At a small scale (1 m^{2}), species richness also increased at the lower summit (from 12.5 ± 2.87 to 15.5 ± 3.12 species on the CP1 summit). The cover of 17 species significantly decreased, while that of 5 increased. There were significant linear relationships between species richness and altitude and climatic variables. The main newcomers were species from the lower altitudinal zones and their percentage was highest on the southern slope. Endemics and cold-adapted species were not seriously endangered. In the Central Caucasus we do not consider climate warming as the primary driver of the changes of plant richness and competition.

Keywords: Alpine plant diversity, global climate change, GLORIA-Europe, richness, species cover

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