We sampled collembolan communities in 11 coal mine spoil tips (locally called 'terrils') from the North of France, and their surroundings, in various stages of vegetation development (bare soil, herb, shrub and tree vegetation). We wondered whether species, functional trait (Community Weighted Mean trait or CWM) composition and trait diversity (Rao's quadratic entropy) responded to the particular environment of coal mine spoil tips (here called 'terril' effect) and to successional effects and which of these three sets was the best indicator of soil and vegetation effects, taking into account that spoil tips were spatially distant and idiosyncratic (e.g. varying in height, area, past

Spoil tip production is one of the most extreme means of soil destruction, replacing the native soil with a coarse substrate. In this paper, we aim to determine the colonization of soil biota in new substrates, using collembola assemblages as an indicator. In Northern France, we sampled collembola communities in 11 coal mine spoil tips and their surroundings divided in four stages of vegetation development: bare soil, meadow, shrub and tree covers. We demonstrated that collembola assemblages of spoil tips were different from those observed in the surrounding native soil. Collembola communities on bare soil were characterized by pioneer (based on the Indval index) or exotic species (new in Northern France). However, homogenization occurred with development of vegetation cover. Indeed, our data showed no difference in springtail diversity between spoil tips and their corresponding environments regarding the tree vegetation cover. Using the Indval method, we defined pioneer, colonizing, opportunist or stenoecious species as a function of substrate affinities. Using the same method, we defined specialists, elective, preferring or indifferent species as a function of vegetation cover affinities, showing similarities with previously published surveys. Hence, our results were obtained by a focused analysis of species and their particularity. Finally, we discussed the interest in and the complementarity between the species analysis approach and the methodology dealing with functional traits and of its importance in the decision process of restoration and/or conservation of nature.

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