New approach for the classification of the Black Pine forest communities in Bulgaria was made in the paper. The analysis of forest pytocoenoses from Vlahina, East and West Rhodopi and Balkan Range Mountains confirmed their separation into two classes – Quercetea pubescentis (low-altitudinal) and Erico-Pinetea (high-altitudinal). The second class is represented from one polymorphic association Seslerio latifoliae-Pinetum nigrae whereas the other group is represented from two new associations. The association Junipero deltoidi-Pineteum pallasianae is more related to the surrounding thermophilous oak forests as well as the association Lathyro laxiflori-Pinetum pallasianae is more similar to the hornbeam and beech forests.

The present work is a floristic and phytocoenological study of rice fields in the Thracian Lowland, South Central Bulgaria. Two species new to the Bulgarian alien flora were found as a result: Heteranthera reniformis (Pontederiaceae) and Rotala ramosior (Lythraceae). The class Oryzetea sativae is documented with phytocoenological relevés for the first time in Bulgaria.

Aesculus hippocastanumL. (European Horse-chestnut) constitutes a biogeographical relict species of the Balkan Peninsula, occurring in isolated and topographically distinct localities in Albania, Bulgaria, Greece and North Macedonia. Despite its great botanical, ornamental and pharmaceutical value, a thorough investigation ofAe. hippocastanumhabitat diversity in its native distribution range has not been conducted yet. The present study aims at the syntaxonomic classification and ecological features of plant communities dominated by this species across its overall native distribution range. On the basis of 55 phytosociological relevés, five ecologically, floristically, and spatially well differentiated clusters were identified, with the main revealed gradients of differentiation being geographic location (longitude, latitude), altitude, annual precipitation and precipitation seasonality. The distinct microhabitats with a special refugial character where these plant communities occur meet the species’ requirement for relatively high air and soil humidity. They have allowed the preservation ofAe. hippocastanumthrough time highlighting their great conservational value. The last one could be useful for the implementation of some appropriate measures for effective conservation of these communities.

A rare species, endemic to the European part of Turkey: Centaurea kilaea Boiss., was found on the dunes at Veleka River Mouth, Southern Black Sea Coast, Bulgaria. This newly found population is a small one - comprising of 43 individuals, participating in the species composition of typical psammophytic vegetation (white dunes). The proximity of the beach at Igneada in Turkey has probably allowed spontaneous dispersal (by wind or maybe ants or seabirds) to the Bulgarian territory. The very limited size and small number of the population, as well as the high dynamics of the coastal strip in this area, call into question its long-term existence in Bulgaria.

Coastal beach–dune systems along the Western Black Sea Coast represent geomorphologically complex and ecologically valuable environments that have been increasingly affected by long-term urbanisation and recreational pressure. This study examines the geomorphological settings, sedimentary connectivity and associated Natura 2000 dune habitats within two urbanised beach–dune systems, Pobeda (Burgas) and Asparuhovo (Varna), to improve their cadastral documentation and support objective conservation assessment. The analysis is based on high-resolution UAS-LiDAR surveys, complemented by UAS photogrammetry and field observations, allowing detailed three-dimensional characterisation of dune landforms, surface morphology and habitat patterns. The results identify foredune-dominated system architectures in both study areas, with the Pobeda (Burgas) and Asparuhovo (Varna) beach–dune systems comprising embryonic dunes, established foredune ridges and low-relief foredune plains, variably developed and spatially fragmented as a result of long-term urbanisation and recreational pressure, and spatially associated with dune habitats. Despite substantial anthropogenic modification, these elements remain recognisable, although locally fragmented and morphologically degraded. Subtle topographic changes related to trampling, informal access routes and surface compaction were detected, particularly affecting foredune crests and foredune plains, with implications for sediment transport continuity and habitat stability. The study shows that conventional habitat inventories alone are insufficient for capturing such changes. Integrated geomorphological and habitat analysis based on UAS-LiDAR provides a reliable framework for accurate mapping, conservation status assessment and informed consideration of coastal dune systems within the Natura 2000 network and related protection schemes.

Acmaeoderella (Euacmaeoderella) villosula (Steven, 1830) is established as a new species for Bulgaria. It is an East Mediterranean-Iranian-Turanian element of the fauna of Balkan Peninsula. This is third country report of the taxon for the Balkan region. In Bulgaria, A. (E.) villosula is most similar to Acmaeoderella (E.) subcyanea (Reitter, 1890), and this paper presents the main diagnostic characters that allow the distinction of these species. With this record, the total number of known Bulgarian Acmaeoderella species and subspecies increases up to 11.