The role of roadside and concrete surfaces in facilitating the spread of Sedum caespitosum (Cav.) DC. in the Pannonian Ecoregion

Szabolcs Kis ¹, Henrietta Bak ¹, Réka Fekete ², Gusztáv Jakab ³, Attila Molnár V. ¹

HUN-REN-UD Conservation Biology Research Group, University of Debrecen, Department of Botany ¹, HUN-REN Centre for Ecological Research, Seed Ecology Research Group ², Eötvös Loránd University, Department of Environmental and Landscape Geography ³

Sedum caespitosum is an annual plant species characteristic of Mediterranean and sub-Mediterranean regions. Within the Mediterranean area, it predominantly inhabits pioneer environments, including open-soil and stony-loamy habitats. Sedum caespitosum is a rare species within the Pannonian Ecoregion. It is classified as a rare species on the Red List of Flora of Romania, recognised as rare in Serbia, and considered potentially endangered in Hungary, where it is protected under national conservation legislation. However, it is also frequently found in anthropogenic habitats, such as along roadsides and within urbanised environments. This study aimed to evaluate the geographical distribution of the species along roads, the population sizes within roadside environments and other anthropogenic habitats (e.g., concrete surfaces near oil wells), and the spatial distribution of individuals in relation to their proximity to roads. For this study, road sections within the Pannonian Ecoregion in Serbia, Romania, and Hungary were surveyed between late March and early May 2023. During sampling, 100-metre segments were examined, documenting the presence or absence of Sedum caespitosum, estimating population sizes, and measuring the distance of individuals from the road where the species was present. A total of 406 sampling points were surveyed within roadside habitats, with Sedum caespitosum detected at 20 of these locations. The average population size was 5,293 individuals, ranging from a minimum of 4 to a maximum of approximately 15,000 individuals. However, within an anthropogenic habitat located further from the road, a population of approximately 60,000 individuals was identified. Overall, the distance of the observed individuals from the road ranged from 1 cm to 370 cm, with a median value of 19 cm. An important conclusion is that for certain roadside populations, the species was found in areas where it does not occur in the surrounding landscape. This suggests that roads may influence the distribution of the species in continental climatic conditions. As ecological corridors, motorways can facilitate the dispersal and expansion of rare plant species.

Main author career stage: PhD student

Contribution type: Poster

First choice session: 1. Systematics, phylogenetics, biogeography and evolution

Second choice session: 2. Ecology