The conservation of the endemic vascular flora of Ascension Island and threats from alien species

Abstract

We present the first assessment of the endemic vascular flora of Ascension Island for over 20 years. Combining new with existing data the following IUCN Red List categorizations are proposed: Anogramma ascensionis, Dryopteris ascensionis, Oldenlandia adscensionis and Sporobolus durus (Extinct); Pteris adscensionis and Euphorbia origanoides (Critically Endangered); Sporobolus caespitosus (Vulnerable); Asplenium ascensionis, Marattia purpurascens and Xiphopteris ascensionensis (Near Threatened). The primary cause of the four presumed extinctions appears to be introductions of exotic species and subsequent alteration of ecological conditions. M. purpurascens, A. ascensionis , and X. ascensionensis appear to be under no immediate threat of extinction, although long-term survival is uncertain. E. origanoides, P. adscensionis , and S. caespitosus require active conservation measures to ensure their survival.