Seasonal and microhabitat variability in the demography and morphology of Ericaria selaginoides (Linnaeus) from a mid-western Alboran sea population: Characterization and pilot restoration experience

Abstract

This study aimed to assess the seasonal population dynamics and morphological changes of the canopy-forming macrophyte Ericaria selaginoides from a mid-western Alboran sea population (La Araña, Málaga, Spain). Demographic and morphological variables were analysed in relation to coast orientation and microhabitat, in three seasonal samplings in 2021. Ericaria selaginoides presented a population cover of 22±18% in summer to 42±22% in winter. Population density was higher in the southwest, for all seasons and microhabitats, reaching maximum values in winter, exposed to higher hydrodynamic forces. Individuals from SW tide-pools showed a gradual increase in length during the growth season. Summer individuals from tide-pools had higher bushiness index than in intertidal platforms. Juveniles of E. selaginoides reached 1.4±0.5 mm after 53 days of ex situ culture. Spring storms limited the growth of E. selaginoides and explained losses in population cover over the growing season. This fact, together with human trampling and scouring, also led to an unfruitful ex situ restoration, making essential to redesign restoration strategies for exposed intertidal habitats. Since extreme weather events will become more frequent with global change, it might contribute to this population decline by constraining its growth and recruitment.