Biological information and comments on Halophila decipiens meadows of the Canary Islands (Hydrocharitaceae, Magnoliophyta)

Abstract

Halophila Thouarsis a pantropical genus of small size seagrasses. Halophila decipiens Ostenfeld forms deep-water seagrass beds extending from 15-40 m in the Canarian coasts which constitute the association Halophiletum decipientis Wildpret & M.C. Gil. H. decipiens is a protected species that was considered as a plant of “special interest” by the Canary Islands Endangered Species Catalogue, BOC 2001/ 097, and Halophiletum decipientis was considered by the European Commission, DG Environment, 1999, “Habitat of Community Interest” (No 111022). It shares habitat with Cymodocea nodosa (Ucria) Ascherson, also considered under protection, as “sensitive to habitat disturbance”, BOC 2001 / 097, and the community Cymodocetum nodosae is also “Habitat of Communitarian interest” (No 111021). In this paper the evolution of Halophiletum decipientis in recent years is shown, and the possible threat of the habitat because of the intromission Caulerpa racemosa var. cylindracea (Sonder) Verlaque, Huisman et Boudouresque, an invasive Australian chlorophyte, is considered.