Conservation actions in Polystichum drepanum (Sw.) C. Presl, a critically endangered fern from the island of Madeira

Abstract

In vitro culture techniques, using spores, were used to propagate the critically endangered fern Polystichum drepanum, in order to reinforce its known natural populations. In 1998 and 2010, a total of 194 plants of P. drepanum were reintroduced at Ribeira do Inferno, a historical habitat of this species and the source of the spores used in this research. In 2021, we observed that, only two of those plants had survived, without any indication of natural regeneration. Reintroduction failures and new reintroduction actions are discussed herein in order to promote the long-term conservation of this species.