The Biodiversity Foundation, a public foundation of the Government of Spain, under the Ministry of the Environment and Rural and Marine Affairs, and the Spanish National Research Council, CSIC, have worked together for four years on the project “Invasion of the Cabrera Archipelago National Park by introduced algae: dynamics of the invasion and effects on benthic communities”. in collaboration with the Autonomous National Parks Agency.

This project addresses one of the main problems of biodiversity, which is the invasion of exotic species, and assesses the effects they have on habitats and priority and native species of our ecosystems, such as the meadows of Posidonia oceanica. On the other hand, it highlights the need for a special effort to be made in prevention, since the eradication of invasive species is shown to be excessively costly and complicated, especially in the marine environment.

The aim of this initiative has been to determine the expansion dynamics of three invasive allochthonous algae, Caulerpa racemosa, Lophocladia lallemandii and Womersleyella setacea in the Cabrera Archipelago National Park, as well as to verify their effects on marine communities. Thus, the CSIC has studied the distribution and abundance of these species, as well as the organisms that favor their invasion.

From this project it can be deduced that Lophocladia lallemandii is distributed between 5 and 35 meters deep, displacing communities of photophilic algae, hemisciaphyllous algae and meadows of Posidonia oceanica. On the other hand, Caulerpa racemosa has a greater biomass and cover between 25 and 50 meters deep, negatively affecting the detrital and maërl bottoms, the coralligenous and hemisciaphyllous algae communities. On the other hand, Womersleyella setacea always develops below 25 meters, altering the communities of coralligenous and hemisciaphyllous algae.

Another fact confirmed by the scientists who have prepared this study is that sexual reproduction has only been observed in Lophocladia lallemandii, which favors its rapid expansion and currently makes it difficult to implement measures capable of stopping its dispersal. The other two species reproduce vegetatively through the dispersal of small fragments, so their progress, and especially in the case of Caulerpa racemosa, is probably favoured by fishing gear.