Mapping Hedera crebrescens with citizen science method

Virág Grónás ¹, Péter Bodor-Pesti ², Beáta Darabosné Maczkó ³, Mária Höhn ⁴

Hungarian University of Agriculture and Life Sciences ¹, Hungarian University of Agriculture and Life Sciences, Institute for Viticulture and Oenology ², Hungarian University of Agriculture and Life Sciences Entz Ferenc Library and Archives ³, Hungarian University of Agriculture and Life Sciences, Institute of Agronomy, Department of Botany ⁴

Climate change has triggered major changes in the composition of natural and anthropogenic ecosystems and often resulted in the decline of natural population communities and the expansion of several, mainly alien species. The so-called lianification is also the result of the global climate change. The phenomenon refers to the uncontrolled spread of the evergreen climbers, due to mild winters, such as ivies. Hedera crebrescens Bényei-Höhn, an ivy species identified in 2017 at the Department of Botany of the former Szent István University (now Hungarian University of Agriculture and Life Sciences), Buda Campus, is one of the winners of the climate change. Due to its slight frost sensitivity, this garden species did not cause any problems earlier, but the observations over the past several years indicated that this ivy species started to spread and is even displacing native ivy (Hedera helix) and other native species from their natural habitats. Our aim was to reveal the present distribution of Hedera crebrescens and the evaluation of its invasive behaviour. We used citizen science, to collect distribution data. This method is often used in nature conservation research and to study the impact of climate change. In our university we initiated the Ivy Mapping Project which has been going on for two years with the help of volunteers. Since one of the defining traits of the species are the fruits, the main collection period is during the ripening of fruits, primarily in winter. To map species’ distribution, we are collecting data from volunteers asking them to provide the locations where this ivy occurs. According to the data received so far (more than 270 H. crebrescens individuals), the species is most frequent around Budapest and in Pest County, but we received data from Komárom-Esztergom, Bács-Kiskun, Heves counties too. H. crebrescens individuals were also reported from Slovakia and Austria. Most individuals were found crawling on fences, and less were found climbing on trees. H. crebrescens was previously identified as H. hibernica. However, H. hibernica is tetraploid, but cytological studies have confirmed that H. crebrescens is a diploid species. Molecular studies also supported the distinct position of this taxon. The leaves of the two species are morphologically similar on the vegetative shoots, therefore, morphometric studies were performed aiming at distinguishing the leaves of H. crebrescens, H. hibernica, and H. helix for better identification. The leaves of the collected individuals were characterized with outline analysis. Based on the analyses, H. helix samples were well separated, but the leaves of H. crebrescens and H. hibernica could not be clearly distinguished so far. We plan to continue mapping of H. crebrescens and extending the project with the help of volunteers.

Main author career stage: Master student

Contribution type: Talk

First choice session: 6. Plants, Fungi and Society

Second choice session: 3. Biodiversity and global change