An assessment of the invasion status of terrestrial alien ferns (Polypodiophyta) in South Africa

0542297 - BÚ 2022 RIV ZA eng J - Journal Article
Jones, E. J. - Kraaij, T. - Guerbois, C. - Moodley, Desika
An assessment of the invasion status of terrestrial alien ferns (Polypodiophyta) in South Africa.
South African Journal of Botany. Roč. 131, july (2020), s. 64-73. ISSN 0254-6299. E-ISSN 1727-9321
Institutional support: RVO:67985939
Keywords : alien ferns * geographic range * invasive plants
OECD category: Ecology
Impact factor: 2.315, year: 2020
Method of publishing: Limited access
https://doi.org/10.1016/j.sajb.2020.02.008

A recent global assessment of terrestrial alien true ferns (Polypodiophyta, hereafter alien ferns) showed that alien ferns have a high probability of becoming naturalised or invasive once introduced. We provide the first systematic assessment, based on field surveys, of the invasion status of this large taxon in South Africa. Thirteen species of alien ferns were recorded outside of cultivation and subsequently identified as invasive in South Africa. Surveys were focused in known hotspots of alien and native ferns, with invasion density peaking along the eastern coastal belt of South Africa. Within the surveyed areas, alien ferns commonly occurred with other invaders, closer to water and often in indigenous forests. The species considered in this study generally occurred in similar habitat types across their native and globally introduced ranges (including South Africa). The potential spread of alien ferns in South Africa appears limited when compared to other major invaders, however, their common occurrence in indigenous forests highlights a concern for native, co-habiting fern species (in terms of competition). Our study provided regulatory insight for 12 previously unregulated alien fern species in South Africa. We propose that eradication remains feasible for Diplazium esculentum, Doodia caudata, Lygodium japonicum, Phlebodium aureum and Platycerium bifurcatum. A risk analysis for Sphaeropteris cooperi classified the species as high risk and comprised the first quantification of risk for any alien fern species (inclusive of aquatics) in South Africa. The information put forward in this study can be used to inform risk analyses for the remaining species in South Africa, as well as countries with similar habitats and climates. Furthermore, widely traded species need to be identified as candidates for future risk assessment since horticulture is an important introduction pathway for alien ferns globally.
Permanent Link: http://hdl.handle.net/11104/0319745