Rapid recovery of native habitat-builders following physical disturbance on pier pilings offsets colonization of cryptogenic and non-indigenous species in a Chilean port

Abstract

Examining the effects of disturbances within marine urban communities can shed light on their assembly rules and invasion processes. The effects of physical disturbance, through the removal of dominant native habitat- builders, were investigated in the recolonization of disturbed patches and colonization of plates on pier pil- ings, in a Chilean port. On pilings, disturbance substantially affected community structure after 3 months, although it slowly converged across treatments after 10 months. On plates, cryptogenic and non-indigenous species richness increased with removal severity, which was not observed in natives. Opportunistic taxa took advantage of colonizing at an early successional stage, illustrating a competition-colonization trade-off, although indirect effects might be at play (e.g. trophic competition or selective predation). Recovery of the habitat- builders then occurred at the expense of cryptogenic and non-indigenous taxa. Whether natives could continue winning against increasing propagule and colonization pressures in marine urban habitats deserves further attention. The interactions between disturbance and biological invasions herein experimentally shown in situ contribute to our understanding of multiple changes imposed by marine urbanization in a growing propagule transport network.