Trait responses to direct drivers and effects on multiple macrofauna-mediated ecosystem functions

As humans are facing challenges related to climate change, biodiversity loss and increasingly threatened ecosystems, there is a need to understand human-induced pressures, effects and feedback processes in the marine environment. Our study therefore aimed to identify environmental and anthropogenic drivers for coastal macrozoobenthic communities and the implications for macrofauna-mediated ecosystem functions. A large spatial-temporal data set combining environmental and macrofaunal data allowed us to highlight exposure and human-induced stressors as main drivers for the macrofaunal communities in the Åland archipelago (northern Baltic Sea). A eutrophication gradient from sheltered inner to exposed outer areas was associated with a change in species- and trait-composition, and a change in dominance from r- to K-strategists in the invertebrate community. Sediment properties were significant drivers in explaining macrofaunal structural diversity patterns. The decrease in abundance, biomass and species richness in muddy sediments was associated with a reduction in bioturbation and bioirrigation potential indices. Environmental and human-induced pressures reduced the availability of macrofauna as food resource for mesopredators (i.e. benthivorous fish). Our results provide a deeper understanding of environment-community relationships and the interplay between biotic and abiotic ecosystem components regarding human-induced pressures.