New Database Maps Southern Caucasus Plant Life

The Caucasus region, situated at the critical intersection of Europe and Asia, has long been recognized as a premier hotspot for global biodiversity. Despite its extraordinary ecological significance, the area has remained notably underrepresented in the vast digital repositories of vegetation data that drive modern ecoinformatics. To address this significant gap, researchers have introduced the Transcaucasian Vegetation Database, a comprehensive resource that compiles, stores, and shares detailed vegetation-plot records from the Southern Caucasus. This novel dataset, identified by the Global Index of Vegetation-Plot Databases code AS-00-005, specifically targets the countries of Armenia, Azerbaijan, and Georgia, aiming to provide a unified scientific foundation for understanding one of the world’s most biologically unique territories. The establishment of this database marks a pivotal step in integrating regional botanical knowledge into the broader international scientific framework, ensuring that the complex flora of this mountainous region is no longer siloed in isolated national archives or unpublished theses.

The Caucasus is a mountainous region located in the middle sector of the Alpine–Himalayan orogenic belt, stretching between the Black and Caspian Seas. This geographic positioning creates a broad elevation gradient, ranging from the Caspian Sea shore at -29 meters to the peak of Mount Elbrus at 5,642 meters, making it the broadest in western Eurasia. The region is characterized by rugged topography and a diverse array of geological bedrock, including limestone karst areas, neovolcanic zones, and ophiolite outcrops. These physical features, combined with significant climatic gradients, support an exceptionally high level of biodiversity. For instance, the Colchic mountains in western Georgia receive up to 4,500 millimeters of annual precipitation, representing one of the wettest areas in the region, while the arid lowlands of Azerbaijan receive only 200 millimeters per year. This environmental variety, coupled with the region’s status as a biogeographic crossroad between the Circumboreal and Irano–Turanian Floristic Regions, has fostered a rich tapestry of plant life that includes numerous ancient relicts and high rates of species endemism.

The Transcaucasian Vegetation Database currently contains 2,882 vegetation plots, representing a nearly century-long span of phytosociological research. The oldest records in the collection date back to 1929, while the most recent were sampled in 2022, and the collection is actively ongoing. All plots within the database were sampled using the Braun-Blanquet phytosociological approach, a standardized method that allows for consistent comparison of plant community structures across different sites and time periods. The data are stored in the TURBOVEG software, which is widely used in vegetation science for its robust handling of species cover and abundance data. By digitizing plots from numerous literature sources, including papers, monographs, and unpublished project reports, the researchers have created a dataset that synthesizes historical knowledge with contemporary field observations. This integration of archival and new data ensures that the database captures long-term trends in vegetation composition, providing a temporal depth that is essential for understanding ecological changes in the region.

Geographically, the database covers a wide area, with the majority of plots located in Georgia, which accounts for 80% of the total records. Azerbaijan contributes 15% of the plots, followed by Russia with 4% and Armenia with 1%. The geographic coordinates are available for 84% of the plots, with 36% of these having high precision of 25 meters or less, which is crucial for accurate spatial analysis and future resurveys. The remaining plots, often from older literature, may have lower precision or lack coordinates entirely, but they are still included to provide a comprehensive overview of national vegetation patterns. The elevation of the plots ranges from sea level to 3,600 meters, with an average of 1,465 meters. The distribution of plots by elevation shows a bimodal pattern, with peaks in the lower forest belt and the subalpine and alpine zones. This wide range of environmental conditions allows researchers to study how vegetation varies across different altitudinal gradients, a key factor in understanding the impacts of climate change on mountain ecosystems.

The taxonomic composition of the database is equally impressive, encompassing 2,500 taxon names, including 2,305 species of vascular plants from 139 families and 195 species of bryophytes from 39 families. The most frequent vascular plant families are Asteraceae, Poaceae, Fabaceae, and Rosaceae, which are dominant in many of the region’s grasslands and forests. In terms of specific species, the database highlights the prevalence of deciduous broad-leaved forests, with trees such as Carpinus betulus and Fagus orientalis appearing in 20% of all plots. Other common species include Fraxinus excelsior, Quercus petraea subsp. iberica, and Tilia begoniifolia. The understory is rich with herbs and shrubs such as Galium odoratum, Ranunculus oreophilus, and Leontodon hispidus. While alien species originating outside western Eurasia are relatively scarce, the database does record the presence of a few invasive species, such as Oplismenus undulatifolius and Robinia pseudoacacia, which are primarily found in the low and warm parts of Transcaucasia. This detailed taxonomic information provides a baseline for monitoring biodiversity and assessing the spread of invasive species in the region.

The database also includes environmental data such as soil pH, slope inclination, and aspect, which are critical variables for understanding the drivers of vegetation diversity. For a significant portion of the plots recorded during recent field expeditions, soil pH was measured using portable devices, with values spanning from 3.8 to 8.0 and an average of 6.3. These data, combined with the species composition and cover values, allow for sophisticated ecological analyses that can identify the relationships between soil properties and plant community structure. The plot areas vary significantly, ranging from less than 1 square meter to over 400 square meters, reflecting the diverse methodologies used in different studies. This variability in plot size is an important consideration for researchers using the data, as it may affect the comparability of species richness and abundance metrics. However, the standardization of the Braun-Blanquet approach helps to mitigate some of these issues, providing a consistent framework for analyzing plant community composition across different plot sizes and types.

The Transcaucasian Vegetation Database is not merely a static repository of data but a dynamic tool that is already being used in numerous international projects. The plots are currently being analyzed for various aspects of botanical, functional, and ecological diversity, contributing to a deeper understanding of the region’s biodiversity. The data are also being used in projects focused on large-scale vegetation classifications, alien species monitoring, and biodiversity assessments. Furthermore, the database provides valuable information for nature conservation efforts, including habitat mapping, environmental management planning, and restoration projects. The high-precision coordinates of many plots make them suitable for future resurveys, which can detect changes in vegetation structure and plant species assemblages over time. This longitudinal aspect of the database is particularly important in the context of ongoing climate change, which is expected to bring new threats such as more frequent droughts, desertification, and shifts in the upper treeline. By providing a baseline of current vegetation conditions, the database enables scientists to quantify the impacts of these changes and develop effective strategies for mitigating them.

The creation of the Transcaucasian Vegetation Database represents a significant achievement in the field of vegetation science, filling a critical gap in the global network of vegetation-plot databases. The region’s unique biodiversity and the challenges it faces due to anthropogenic pressures and climate change make it an essential area for study. By compiling and sharing this data, the researchers have provided a valuable resource for the international scientific community, facilitating collaboration and advancing our understanding of one of the world’s most important biodiversity hotspots. The database is available upon request through the Global Index of Vegetation-Plot Databases and the European Vegetation Archive, ensuring that it can be accessed by researchers worldwide. As data collection continues, the database will grow in both geographic and ecological scope, incorporating new field data and digitized literature. This ongoing expansion will further enhance its utility for a wide range of thematic projects, from basic ecological research to applied conservation biology. The Transcaucasian Vegetation Database stands as a testament to the power of collaborative science in addressing global environmental challenges and preserving the rich natural heritage of the Southern Caucasus.

Subject of Research: Phytosociological database development for the Southern Caucasus region

Article Title: Transcaucasian Vegetation Database – a phytosociological database of the Southern Caucasus

Article References: Novák, P., Kalníková, V., Szokala, D., Aleksanyan, A., Batsatsashvili, K., Fayvush, G., Kolbaia, S., Nakhutsrishvili, G., Sedláček, V., Štěrba, T., & Zukal, D. (2023). Transcaucasian Vegetation Database – a phytosociological database of the Southern Caucasus. Vegetation Classification and Survey, 4, 231-240. https://doi.org/10.3897/vcs.105521

Image Credits: AI Generated

DOI: 10.3897/VCS.105521

Keywords: Caucasus, Vegetation Database, Biodiversity, Phytosociology, Braun-Blanquet, Ecoinformatics, Plant Ecology, Conservation, Georeferencing, Flora, Transcaucasian, Vegetation