Different effects of Caulerpa racemosa on two co-occurring seagrasses in the Mediterranean

摘要: Inthisstudy,wepresenttheresultsofa14-monthfieldexperimentontheeffectsoftheintroducedalgaCaulerparacemosa on two co-occurring native seagrasses,Cymodocea nodosa and Zostera noltii. The experiment wasconducted in a mixed shallow seagrass bed along the Tuscan coast (Italy) that has been invaded by alga since1995. Treatment consisted of manipulation presence (presence vs. removal). Responsevariables considered for Cymodocea were shoot flower (both male female) density forZostera noltii vegetative reproductive density, first species being dioecious lattermonoecious. Results have indicated influences both plants. WithCymodoceanodosatheshootdensitywasloweredandwithZosteranoltiiitwasincreasedinareasinvadedbythealga. Both andZostera found to besignificantly higher where Caulerpa racemosa was present relative it removed. Hence, differenteffects, either positive or negative, depending response variable.Potential mechanisms interaction are discussed.