Experimental evaluation of habitat preferences of invasive crayfish species in Europe in context of co-invasions

Biological invasions commonly occur in series, leading to new interactions between multiple invaders in novel habitats. Their coexistence or competitive exclusion depends on the width and overlap of their habitat preferences. We evaluated the habitat preferences of North American crayfishes invasive in Europe: Faxonius limosus ( FL ), Procambarus clarkii ( PC ) and Procambarus virginalis ( PV ), to check their selectivity for substratum grain sizes, shelter sizes, and shells of various bivalve species as shelters. All the species exhibited overlapping grain size preferences (diameter: 2 mm), PV being the least selective (preference extending to 5 mm). FL selected smaller shelters than PC . FL and PC preferred shells of the alien Sinanodonta woodiana over native unionid mussels, whereas PV was non-selective for unionid shells. All species avoided the smaller Corbicula shells. Altogether, in our study, FL was the most, whereas PV the least selective, and PC the most explorative. The high overlap of habitat preferences and low probability of habitat partitioning suggests that the coexistence of these crayfishes will be temporary, and FL is likely to get displaced by new Procambarus invaders, P. clarkii being more explorative and aggressive, P. virginalis being less selective.