Earthworm indicators as tools for soil monitoring, characterization and risk assessment. An example from the national Bioindicator programme (France)

Guénola Pérès (1) , Franck Vandenbulcke (2) , Muriel Guernion (1) , Mickael Hedde (3) , Thierry Beguiristain (4) , Francis Douay (5) , Sabine Houot (6) , Denis Piron (1, 7) , Antoine Richard (8) , Antonio Bispo (9) , Cécile Grand (10) , Laurence Galsomies (10) , Daniel Cluzeau (1)

1 ECOBIO - Ecosystèmes, biodiversité, évolution [Rennes]
2 NA - Neuroimmunologie des annélides
3 PESSAC - Physicochimie et Ecotoxicologie des SolS d'Agrosystèmes Contaminés
4 LIMOS - Laboratoire des Interactions Microorganismes-Minéraux-Matière Organique dans les sols
5 LSE - Laboratoire Sols et Environnement
6 EGC - Environnement et Grandes Cultures
7 LEFE - Laboratoire Ecologie Fonctionnelle et Environnement
8 LAS - Laboratoire d'Analyses des Sols
9 Département Animation de la Recherche Déchets & Sols
10 ADEME - Agence de l'Environnement et de la Maîtrise de l'Energie

Considering the limited number of bioindicators available to assess soil quality, a national research programme was set up in France to develop such indicators (2006-2012), the "Bioindicator" programme. This programme tested 47 biological parameters (i.e. microorganisms, fauna, flora) including earthworms, in several sites differing in terms of land use, contamination type - PAHs or metals - and pollution levels. The present study proposes some study objectives for bioindicator approaches, based on the earthworm results from the programme. Therefore, different earthworm descriptors were tested at the community level (e.g. abundance, biomass, species and functional structures, and ecological traits) as well as the organism level (i.e. measuring the metallothionein coding gene expression level in earthworms). The present results, obtained from the programme's spring 2009 sampling campaign, discriminated among the different descriptors and showed that earthworm and endogeic abundance as well as the individual weight of endogeics seem to be good indicators in non-contaminated (cultivated) sites, while the ecological structure, namely the proportion of anecic vs. endogeic species, and the proportion of non-vulnerable species should be used as indicators of contaminated soils. Furthermore, the first results obtained for Lumbricus terrestris and L. rubellus rubellus are encouraging as they show that metallothionein expression increases in metal-contaminated soils. The relevance of these descriptors, which have to be considered in study objectives, requires the analysis of 2010 results.

Mots clés: Bioindicator; Monitoring; Risk assessment; Earthworm community; Metallothionein gene expression

Domaines: Biodiversité et Ecologie

Guénola Pérès, Franck Vandenbulcke, Muriel Guernion, Mickael Hedde, Thierry Beguiristain, et al.. Earthworm indicators as tools for soil monitoring, characterization and risk assessment. An example from the national Bioindicator programme (France). Pedobiologia, 2011, 54 (sup), pp.77-87. ⟨10.1016/j.pedobi.2011.09.015⟩. ⟨hal-00755525⟩