Are dispersal behaviours of earthworms related to their functional group?

Dispersal plays a key role in the dynamics of ecological communities as it strongly determines the potential of individuals to colonize new habitats. Understanding and predicting species dispersal behaviour is therefore central to any effort at managing or even understanding the formation of communities. In this context, it is essential to understand the influence of environmental and biotic determinants of dispersal. In this work, we assessed these questions using earthworms as model organisms.We assessed the dispersal behaviour of six earthworm species belonging to two different functional groups (i.e. three anecics and three endogeics) in response to three key environmental factors: habitat quality, intraspecific density, and environment homogeneity. We found that habitat quality significantly influenced the dispersal rates of all species. Intraspecific density increased the dispersal rate of the three anecic species but only of one endogeic species. In a homogeneous environment, anecics dispersed further and in greater proportion than the majority of endogeics. Moreover, few anecic species have shown a tendency to follow conspecifics. Overall, anecic species seemed to have a higher active dispersal inclination than most endogeic ones. We found a high variability of our results within each functional groups, which suggests that this classification cannot be used to explain or predict the dispersal behaviour of earthworms.

► Dispersal behaviour in response to 3 environmental factors: habitat quality, intraspecific density and environment homogeneity.
► We compared dispersal behaviour of three endogeics and three anecics.
► No correspondence between functional groups and dispersal behaviour.
► The functional group alone is not sufficient to explain the dispersal behaviour.