Plasticity To Environmental Conditions And Substrate Colonization Mediates The Invasion of Dreissenid False Mussels In Brackish Systems

Abstract

False mussels are recognized as the brackish water equivalent of zebra mussels, although the abiotic and habitat conditions that mediate these invaders’ success are barely known. In this context, we aimed to evaluate the native and non-native geographical distribution of Mytilopsis species worldwide and assess biological traits, environmental condition, and habitat associated with false mussels in native and invaded systems. Our hypothesis is that Mytilopsis invasion is driven by species plasticity to environmental conditions and substrate use in brackish systems, where the colonization of non-native populations is favored by great availability of artificial substrates and tolerance to wide ranges of environmental conditions. Besides, this study provides the occurrence range and distribution patterns of Mytilopsis species within their introduced and native areas and tracks the spread of introduced populations worldwide. Considering the five species evaluated, M. leucophaeata and M. sallei are the most widespread, while M. adamsi, M. trautwineana, and M. africana showed more restricted geographic distribution. In the last decades, M. leucophaeata and M. sallei consolidated and expanded their distributions. Environmental conditions were significantly different between native and non-native areas, where Mytilopsis populations presented significantly higher densities. Non-native populations exhibited remarkable plasticity concerning habitat colonization that was more frequent on artificial substrata. Mytilopsis populations presented significant differences on their biological traits, habitat environmental conditions, and substrate use between native and non-native areas. These species seem to adapt to the conditions of invaded systems, changing their preferences, which reflects plasticity and suggests a potential shift of their realized niches.