Small-scale patches of detritus as habitat for invertebrates within a Zostera noltei meadow.

Seagrass detritus can attract numerous invertebrates as it provides food and substrate within the meadow or in adjacent environments. Nonetheless, several factors could modify the invertebrate response to this habitat. In this study, we tested if epifaunal colonisation of Zostera noltei detritus was related to substrate availability rather than food and whether colonising assemblages were similar according to the meadow structural complexity. Litterbags filled with natural or artificial detritus were deployed within an eelgrass meadow in a Mediterranean coastal lagoon (Thau lagoon, France). Colonisation appeared to be driven by the presence of detritus, with similar assemblages in natural and artificial substrate, but with more individuals than the empty bags, used as controls. There were also no differences according to habitat complexity. These findings show that detritus, acting as a faunal magnet, plays an important role in maintaining biodiversity, as epifauna is a critical trophic link between primary producers and consumers.