Vegetation of low-altitudinal mesophilous forests in south-western Georgia (Colchic Region)
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| Year of publication | 2017 |
| Type | Conference abstract |
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| Description | The aim of our research is to describe and phytosociologically classify unique mesophilous forest vegetation developed on the slopes of the Le sser Caucasus (80- 990 m) belonging to the Colchic Region in SW Georgia. This regi on is characterized by humid and warm-temperate climate and it is supposed to be an important refugium of forest biota during Pleistocene. Local forests harbour many relict species including evergreen shrubs. This vegetation has not been studied using Br aun-Blanquet approach so far. Chestnut-hornbeam and ravine forests of the study region were d ocumented by phytosociological relevés in 2015 and 2016. Basic environmen tal characteristics (altitude, aspect and inclination of slope, cover of rocks, pot ential heat load of site and soil pH) were available for each relevé as well. Subsequently, data were analysed using modified TWINSPAN and ordination analyses (DCA, CCA). Numerical comparison of the distinguished clusters with previously published syntaxa fr om northern Turkey was performed as well. The dataset of 53 relevés was divided into three clusters by mo dified TWINSPAN. Concerning the alliance of Euxinian chestnut-hornbeam forests Castaneo-Carpinion two communities were recognized. Digitalis ferruginea subsp. schischkinii-Carpinus betulus community were forests of drier sites with low cover of evergre en shrubs, species tolerating dry soils (e.g. Asplenium adiantum-nigrum , Viola alba ) were characteristic for this vegetation. The second type was Ruscus colchicus-Castanea sativa community which comprised chestnut-hornbeam forests with well-developed e vergreen shrub layer (e.g. Ilex colchica , Prunus laurocerasus and Rhododendron ponticum ) and often poor herb layer with frequent occurrence of ferns. Euxinian ravine f orests of the alliance Alnion barbatae were represented by a community Polystichum woronowii-Ulmus glabra containing forests with occurrence of noble hardwood trees and specialists of ravine forests in their herb layer (e.g. Asplenium scolopendrium , Polystichum woronowii ). Numerical comparison with previously distinguished associations in northern Turkey highlighted specificity of recorded communities in the broader context of the Euxinian mesophilous forest vegetation. Thus all three clusters were des cribed as new associations ( Digitali schischkinii-Carpinetum betuli , Rusco colchicae-Castaneetum sativae and Polysticho woronowii-Ulmetum glabrae ). Ordination analyses indicated that major turnover in species composition is bounded on variables altitud e, potential heat load of site and soil pH. |
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