The invasive green alga Caulerparacemosavar. cylindracea represents an important threat to the diversity of Mediterranean benthic coastal ecosystems by interfering with native species and modifying benthic assemblages. The present study deals, for the first time, with the temporal and spatialvariability of the biomass and phenology of C. racemosa considering both deep- and shallow-waterpopulations. Two sampling depths (30 and 10 m) were sampled at three different rocky bottom sites every 3 months in the Archipelago of Cabrera National Park (WesternMediterranean). All morphometric variables analysed showed a spatial variation and temporal patterns depending on depth. Between depths, C. racemosa biomass, stolon length, number of fronds and frond length were usually significantly higher at deep-waterpopulations, suggesting that C. racemosa grows better in deep-waters. Deep- and shallow-waterpopulations displayed a high temporal variation although no evidence of seasonal patterns was found, in contrast with what has been reported by other authors. The sources of this variability are still unknown but probably both physical factors and differential herbivory pressures display a key role.

Financial support was provided by the Fundación Biodiversidad and the Ministry of Science and Education of Spain (Grant CTM2005-01434/MAR and GRACCIE project C5D2007-00067). EC was partially funded by a EU Marie Curie Fellowship (MEIF-2006-041315).

6 páginas, 3 tablas, 1 figura.

Peer reviewed