First report of Salvinia molesta in the Canary Islands, Spain
Salvinia molesta (Salviniaceae: EPPO List of Invasive Alien Plants) is native to Brazil and in the EPPO region the species has been reported from Austria, Belgium, Denmark, France (including Corsica), Germany, Italy, Netherlands, Portugal and the United Kingdom. As an aquatic floating plant species, S. molesta can form dense mats which reduce access to the water for recreation; interfere with various engineering structures such as weirs, block drains and cause flooding. It can have negative impacts on biodiversity by preventing photosynthesis in the water below the mat which can impact aquatic invertebrates and plants. Cultural ecosystem services are negatively affected by the mat forming habit, reducing opportunities for swimming, fishing and boating. In 2014, S. molesta was identified for the first time in the Canary Islands (Gran Canaria), in a ravine called Barranco de Azuaje. The population was found at an altitude of 240 m asl in a lake, near an old abandoned spa. The area of the lake is approximately 600 m2 and the plant covers almost 100 % of the surface. In Spain, S. molesta is considered one of the five species presenting a risk of potential invasion though the current authors do not consider the situation in Gran Canaria as too serious as there are not many habitats for the plant to establish. Control may however be compulsory, as the species is included in the Exotic Invasive Species Catalogue of Spain. Additionally, S. molesta is one of the plant species being risk assessed under the LIFE project.
Sources
Salas-Pascual M, Vega GQ (2016) Salvinia molesta D.S. Mitch. (Salviniaceae), Nueva Cita Para Canarias Y España. Botanica Macaronésica 29, 73-81.