1. 1 Ecosystem vulnerability Biarritz October 18-21 2011 Taxonomic sufficiency of epi- benthic species in scientific bottom trawl surveys A. Brind’Amour, P. Laffargue, J. Morin, M-L. Cochard, S. Vaz Département Ressources Biologiques et Environnement, Ifremer

2. 2 Ecosystem vulnerability Biarritz October 18-21 2011 Context « Identifying organism to the level of taxonomic resolution sufficient to satisfy the objectives of a study » (Ellis 1985) Use higher-taxon level as surrogates for species Historically used in « pollution » studies (Somerfield & Clarke 1995, Bowman & Bailey 1997)

3. 3 Ecosystem vulnerability Biarritz October 18-21 2011 Context Marine Strategy Framework Directive (2008/56/EC) : Achieve Good Environmental Status by 2020  Descriptors 1, 2, 4, 6 (macroinvertebrates) O. albida O. ophiura Anapagurus hyndmanni Pagurus bernhardus Macropodia rostrata Inachus dorsettensis European and institutional fish bottom trawl surveys routinely identify macro and mega-invertebrates epibenthic species (Brind’Amour et al. 2009, Laffargue & Martin 2010)  Some taxa not identified at the species level (experts  )  Misidentification of morphologically similar species

4. 4 Ecosystem vulnerability Biarritz October 18-21 2011 Objectives 1° Assess the taxonomic level to which epibenthic mega and macro-fauna can be studied without losing ecological information (community structure) 2° Compare the results from fish bottom trawl surveys conducted at different spatial scales (coastal bays to shelf) 3° Elaborate some recommandations (e.g. list of species) for which identification can be done at higher-taxon level

5. 5 Ecosystem vulnerability Biarritz October 18-21 2011 Case studies European & French scientifc surveys South Bay of Biscay (EVHOE) North Sea (IBTS) North Shelf Coast Bay of Seine (NourSeine) Bay of Vilaine (NurVil) © Ifremer

6. 6 Ecosystem vulnerability Biarritz October 18-21 2011 Methodology Data* (density) + RefTax (AphiaID) *Done at the five levels: Species, Genus, Family, Order, Morphospecies Community structure and the spatial distribution of the taxa Total 223 species in the 4 surveys 42 morphospecies (i.e. species potentially misidentified) + individual species ~ L. depurator L. holsatus NMDS (Bray-Curtis) HCA (Ward) Rand Index  Assess the similarity betwen the classifications for the five levels

7. 7 Ecosystem vulnerability Biarritz October 18-21 2011 Results Community structure (nMDS) Sediment and depth gradient

8. 8 Ecosystem vulnerability Biarritz October 18-21 2011 Results Community structure (nMDS) Sediment and depth gradient

9. 9 Ecosystem vulnerability Biarritz October 18-21 2011 Results Comparaison (Rand Index) Bay of Biscay R = a + b a + b + c + d

10. 10 Ecosystem vulnerability Biarritz October 18-21 2011 Results Comparaison (Rand Index) Bay of SeineBay of VilaineNorth SeaBay of Biscay R = a + b a + b + c + d 33142427245820385139130378210579151439112298

11. 11 Ecosystem vulnerability Biarritz October 18-21 2011 Conclusions Taxonomic sufficiency seems case-dependent (small vs large scale surveys): degrading the taxonomic information to genus/family less of a problem in species-dominant community (Seine) than in species-rich and evenly composed community (North Sea) In large-scale surveys, misidentification of community structure can reach differences up to 70% (range 10-70%) when taxa are studied at the genus level Identification of morphospecies may be a “compromise” in large- scale surveys encompassing multiple habitats Desperate needs for benthic taxonomists (!) Ongoing work  Increase the number of datasets and different years to test the effect of species richness and evenness

12. 12 Ecosystem vulnerability Biarritz October 18-21 2011 Thank you ! A special thank’s to all the scientists who participated to data collection and species identification (IBTS / EVHOE / NourSeine / NurVil)

13. 13 Ecosystem vulnerability Biarritz October 18-21 2011 Results Low species richness and high dominance High species richness and high eveness gen /sp fam/ sp ord/ sp gen /sp fam/ sp ord/ sp gen /sp fam/ sp ord/ sp gen /sp fam/ sp ord/ sp

14. 14 Ecosystem vulnerability Biarritz October 18-21 2011 Methodology Data* (density) + RefTax (AphiaID) *Done at the five levels: Species, Genus, Family, Order, Morphospecies Community structure and the spatial distribution of the taxa Total 223 species in the 4 surveys 42 morphospecies (i.e. species potentially misidentified) + individual species ~ L. depurator L. holsatus HCA (Ward) IndVal NMDS (Bray-Curtis) Rand Index  Assess the similarity betwen the classifications for the five levels Informs on the taxa within each group and discriminant taxa