Diversity and degradation of the vegetation of mountain belt forests of central Adjara (the Lesser Caucasus), Georgia

Abstract

The Colchis forests contribute to the biodiversity hotspot in the Caucasus eco-region. We investigated the plant diversity of these forests in the central part of Adjara (W Georgia). The aims of our study were (i) to differentiate the forest vegetation diversity in the mountain belt forests by means of phytosociology, (ii) to associate endemic taxa with the revealed forest types, and (iii) to assess degradation of the forest vegetation diversity by means of environmental abiotic and biotic factors. We sampled the forest vegetation on 135 plots with the size of 10 × 10 m2 and 237 plant taxa were recorded. Principal Component Analysis (PCA) was used to reduce environmental variables to a few orthogonal composed variables. The derived factors (PC1, PC2) were used in ordination analysis to group the plot measured forest vegetation diversity. One-way ANOVA was used for the comparison of means between the separated clusters in PCA. Two-Way Indicator Species Analysis (TWINSPAN) and Indicator Species Analysis (ISA) were applied for the association of the plant taxa with the vegetation cluster groups separated by PCA. Our analysis revealed two general ecologically distinct forest types which were characterized as dry and humid forests. Endemic species had the main occurrence in dry forests of the studied territory which are heavily impacted by the local land use. The results indicated that the vegetation diversity of dry forests is under higher threat of degradation than that of humid ones because these forests are not protected and are subjected to non-sustainable forest exploitation. Additionally, many rural and invasive plant species change the native plant assemblages. Based on our findings, we recommend to the organization which manages the local forests to find a balance between the use of forest resources and protection of the unique floristic diversity of local forests in order to avoid their degradation.

Drivers of wood‐inhabiting fungal diversity in European and Oriental beech forests

“…In the western part of the Palearctic, temperate forests are dominated by two species of Fagus : European beech Fagus sylvatica in the West and Oriental beech Fagus orientalis in the East, ranging from eastern Bulgaria to the Hyrcanian forest in Iran. The latter are often Arcto‐tertiary relicts, harboring many endemic plants and animals (Aliev, 2021 ; Fayvush & Aleksanyan, 2021 ; Goginashvili & Tvauri, 2013 ; Mathew et al., 2000 ). While for European beech the impact of forest management on several taxa has been well studied during the last decades (Brunet et al., 2010 ; Gossner et al., 2013 ; Hagge et al., 2019 ; Morales‐Hidalgo et al., 2015 ; Ódor et al., 2006 ), drivers of biodiversity in Oriental beech are not well understood.…”

First pollen record from the Late Holocene forest environment in the Lesser Caucasus

“…The Aghstev Valley was occupied in the Chalcolithic by hunter-gatherers, or pastoral nomads (day-to-day herding or transhumance) (Arimura et al, 2014). Admittedly, the use of wood, which has intensified for the mining activities (Smith et al, 2009;Stöllner, 2021), may have marked a turning point, but it is especially during the last centuries that the forest of the Lesser Caucasus has the most regressed and has deteriorated (Goginashvili et al, 2021). In Armenia, the forest has gone from 18% in the 18th century to 7-8% today (Sayadyan, 2011).…”