According to a CNRS communication dated September 22, 2025, based on a scientific publication in Current Biology co-authored by Yoan Coudert, CNRS researcher at the RDP, ENS de Lyon, together with Saioa Ricou-Dreneuc and Claudine Ah-Peng: "Architectural shift to epiphytism fuels exotic bryophyte invasiveness."
A study published in Current Biology reveals a previously unknown behavior in the invasive moss Pseudoscleropodium purum, also known as "gardeners’ moss", likely introduced accidentally to Réunion Island in the 1960s. Long described as a terrestrial species, it now exhibits a developmental strategy that allows it to colonize tree trunks. This architectural shift, driven by record-breaking growth and developmental plasticity, increases its invasive potential and poses a serious threat to the diversity of many other plant species on the island.
A Terrestrial Moss That Climbs Trees
Human activities are disrupting ecosystems and facilitating the spread of invasive alien species. While more than 2,800 invasive vascular plants have been documented worldwide, mosses are rarely among them. The study reported in Current Biology changes that perspective by documenting a unique case: Pseudoscleropodium purum, native to Europe and commonly called "gardeners’ moss," introduced accidentally to Réunion Island in the 1960s, is now able to colonize tree trunks.
Previously described as a terrestrial species, this moss stands out due to a remarkable transition to an epiphytic lifestyle, meaning it lives attached to other plants. The researchers demonstrated that this new strategy relies on architectural changes such as elongation and multiplication of the main stems, increased production of rhizoids (filamentous structures that provide anchorage), and a growth rate averaging about 10 cm per year, sometimes exceeding 40 cm, a record for terrestrial mosses.
Left: Invasive exotic moss Pseudoscleropodium purum (white arrow tips) covering the forest floor and climbing a native tree trunk in Réunion National Park.
Right: Experimental setup to study the impact of Pseudoscleropodium purum on local plant communities. © Claudine Ah-Peng
Learn more on the CNRS website (Fr)
Reference
Saioa Ricou-Dreneuc ; Claudine Ah-Peng ; Yoan Coudert. Architectural shift to epiphytism fuels exotic bryophyte invasiveness. Current Biology. 2025 Sept. 22. DOI : https://doi.org/10.1016/j.cub.2025.07.068
