Format: ORAL

Joaqun Moreno1, Alejandro Terrones2, Ana Juan3

1 Miguel Hernández University of Elche, Elche, Spain 2 Arid Zones Experimental Station (EEZA-CSIC), Almería, Spain 3 University of Alicante, Alicante, Spain

Soil salinity is one of the most relevant drivers leading to plant zonation in Mediterranean saltmarshes, where germination is a critical stage in the life cycle of many halophytes. The study of how salinity allows the germination and establishment of halophytes in saline environments is a relevant first step to disentangle the assembly processes in theses habitats, where sympatric species occupate separate ecological niches as a result of adaptive differentiation along the salinity gradient. In this framework, the main goal of this study is to assess if the co-occuring halophytes in Mediterranean saltmarshes show different germination patterns along the salinity gradient. Experiments were conducted considering the seeds of perennial co-occuring species in Mediterranean saltmarshes (Arthrocaulon macrostachyum, Salicornia fruticosa, four sympatricLimoniumspecies -L. caesium,L. cossonianum,L. delicatulum,and L. supinum- and Lygeum spartum) and the whole salinity gradient of these habitats (06% NaCl). Our results suggest that the successful establishment of halophytes depends on the germination strategy which implies a rapid germination velocity when the soil salinity decreases, shaping the plant asssembly within the saline habitat. According to the obtained results, two different germination strategies have been defined which favour the adaptation of different halophytes species under favorable conditions. Certain species can germinate along a wide salinity range (e.g., S. fruticosa, L. cossonianum), whereas others are characterised by high germination at low-medium salinities and a reduced germination after high salinity exposure (e.g., A. macrostachyum). These findings provide evidence to shed light on the local assembly processes of halophytic communities and its particular zonation.