Spatio-Temporal Variability of Wrack Along the Northern Portuguese Sandy Beaches

Abstract Wrack accumulations are a source of nutrients on sandy beaches and host invertebrate species, increasing local biodiversity. The distribution these important varies in space time depending the environmental conditions composition species that wrack. Species spatiotemporal variability wrack remain poorly understood some regions. In this study, we evaluated biomass diversity four northern Portugal over course 1 year. results revealed both varied temporally beach tidal level where it was collected. about 20 to 35 times greater at higher than low tide more abundant (87%) twice as diverse two northernmost probably due proximity rocky shores. Large brown temperate boreal macroalgae such fucoids ( Fucus spp., Cystoseira Ascophyllum nodosum ) kelp Saccorhiza polyschides were most taxa Fucoids throughout year, while kelps predominated warmer months, generating 8% produced by However, since large reducing their size recruitment global warming north Iberian Peninsula, could be limited future, compromising crucial functions ecosystems.