Vegetation of Ski Pistes in the Lesser Caucasus (Bakuriani, Georgia): Species Composition, Functional Traits, and Temporal Dynamics

Ski piste construction and maintenance are recognised as significant drivers of vegetation change in mountain ecosystems. The Caucasus has a rapidly developing ski tourism and at the same time is an important hotspot of global biodiversity; the impact of this form of land use on vegetation has not yet been studied in the area. We examined plant community structure, species composition and cover, functional-group biomass, and temporal dynamics along an elevation gradient (1,884–2,685 m a.s.l.) spanning montane to alpine zones at the Didveli ski piste within the Bakuriani ski resort (Lesser Caucasus, Georgia). We compared 36 ski piste plots (18 standard-track and 18 eroded) with 25 adjacent undisturbed control plots using ordination (PCA and CCA), cluster analysis, Indicator Species Analysis, and linear mixed-effects models. We analysed the occurrence of 103 species with a frequency ≥ 5 in these plots. PCA clearly separated control plots from disturbed plots along the axis associated with soil depth, species richness, and aboveground biomass. CCA confirmed that species distributions closely followed this human-impact gradient. Cluster analysis identified floristically distinct groups that broadly corresponded to control, track, and eroded conditions. Indicator Species Analysis revealed that undisturbed plots supported typical alpine meadow species ( Gentiana septemfida, Bromus variegatus, Veratrum lobelianum ), while eroded plots were associated with disturbance-tolerant taxa ( Draba hispida, Arctium lappa ) and track plots with the compaction-tolerant grass Calamagrostis pseudophragmites . Mean aboveground biomass on control plots (2,526 kg ha –1 ) was 2.1–3.0 times higher than on track (1,175 kg ha –1 ) and eroded plots (833 kg ha –1 ). Graminoids and forbs declined sharply under disturbance, whereas legume biomass was resilient across all land-use types, likely owing to nitrogen-fixation capacity. Temporal monitoring (2020–2023) showed stable or increasing biomass on control plots but limited and short-lived recovery on piste plots. These findings demonstrate that ski piste development substantially reduces biodiversity and productivity in the Caucasus Mountain grasslands and underlines the need for targeted restoration and sustainable management strategies.