A trait-based review of migratory behaviours exhibited by microphytobenthos and macrozoobenthos communities of the intertidal habitats of the Wadden Sea

Morgan Hartley

Communities of both microphytobenthos and macrozoobenthos exhibit fluctuations in community composition, due to daily activities and vertical migrations. These behaviours have rarely been explored in the context of entire benthic ecosystems. Trait-based perspectives are infrequently used within this context. Consequentially, there is limited information regarding how these migrations impact the ecology and function of intertidal communities. This trait-based review classifies and describes the short-term migratory behaviours of benthic organisms within the Wadden Sea. Additionally, this review considers the species-specific traits for both microphytobenthos (mobility and resource acquisition) and macrozoobenthos (mobility and feeding traits), exploring the motivation behind these behaviours. For microphytobenthos, mobile species exhibit bulk migratory behaviours, synchronised with tidal and solar changes, migrating to the sediment surface only when low tide coincides with daylight. Resource acquisition traits provide insight regarding the specific timing of these behaviours. Macrozoobenthic organisms display diverse migratory behaviours, demonstrating general trends within mobility trait groups. Again, these behaviours are synchronised with tidal and solar changes, but display different behaviours than the microphytobenthos, with migratory usually occurring at high tide, during the night. This review provides an important baseline of knowledge regarding benthic migratory behaviours`, on which trait-based studies within the WS can be further developed.