Please cite this article in press as: Jacobs, S., et al., The ecosystem service assessment challenge: Reflections from Flanders-REA. Ecol. Indicat. (2015), http://dx.doi.org/10.1016/j.ecolind.2015.10.023 ARTICLE IN PRESS G Model ECOIND-2687; No. of Pages 13 Ecological Indicators xxx (2015) xxx–xxx Contents lists available at ScienceDirect Ecological Indicators j o ur na l ho me page: www.elsevier.com/locate/ecolind The ecosystem service assessment challenge: Reflections from Flanders-REA Sander Jacobs a,b,∗ , Toon Spanhove a , Lieven De Smet a , Toon Van Daele a , Wouter Van Reeth a , Peter Van Gossum a , Maarten Stevens a , Anik Schneiders a , Jeroen Panis c , Heidi Demolder a , Helen Michels a , Marijke Thoonen a , Ilse Simoens a , Johan Peymen a a Research Institute for Nature and Forest (INBO), Government of Flanders, Belgium b Research Group AgricultureIsLife, Université de Liège – Gembloux AgroBiotech, Belgium c Agency for Nature and Forests (ANB), Government of Flanders, Belgium a r t i c l e i n f o Article history: Received 28 May 2015 Received in revised form 6 October 2015 Accepted 9 October 2015 Keywords: Ecosystem services Biodiversity targets Ecosystem assessment Transdisciplinarity Mapping Sustainability a b s t r a c t This paper aims to improve ecosystem assessment practice by sharing the lessons learned from the Flanders Regional Ecosystem Assessment. The ‘EU biodiversity strategy to 2020’, requests the EU member states ‘to map and assess the state of ecosystems and their services by 2014’. However, a large number of member states have yet to start this assessment, and depend on assistance from the European Commission and on experiences from ongoing national assessments. In the region of Flanders (Belgium), several ecosystem service projects have since 2009 led the way to the ‘Flanders Regional Ecosystem Assessment’ (Flanders-REA), led by the governments’ leading research institute on biodiversity. To attain high regional requirements on scientific quality, acceptance and effective local policy impact, this assessment has tackled a number of challenges. The challenges discussed in this paper are obtaining conceptual clarity and consensus across disciplines and partners, the integration of multiple sources of information, critical handling of maps and the inclusion of experts and stakeholders. This paper also critically reflects on the definition of EU targets, their implementation, the current EU assistance to the member states, and the alignment with actual local and global policy needs. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The field of ecosystem services continues a long-standing tradi- tion in economic science and revolves around the sustainable and equitable use of natural resources. After the somewhat polemic promotion of the concept in the 1990s (see Baveye et al., 2013), ecosystem services and especially their valuation recently regained wider attention of high-level policy institutions and the nature con- servation research community (for a critical review of the concept’s history see Baveye et al., 2013; Gómez-Baggethun et al., 2010). This resulted in a broader mainstreaming of the concept and its percolation into various policy documents during the last decade. The Aichi Targets, adopted by the convention on biological diversity (CBD), explicitly put forward a rationale on ecosystem ∗ Corresponding author at: Kliniekstraat 25A, 1070 Brussels, Belgium. Tel.: +32 496156673. E-mail address: sander.jacobs@inbo.be (S. Jacobs). service provision, aiming at sustainability and equity in ecosystem service delivery. 1 The achievement of these targets is envisioned by 2020. In line with this ambition, the European Commission devel- oped a biodiversity strategy for Europe. 2 The strategy is similarly divided in targets and actions and emphasizes the (strict) economic notion more strongly. There are six main targets and 20 actions to help Europe reach its goal. Target two, action five is directly linked to ecosystem services: ‘member states, with the assistance of the Com- mission, will map and assess the state of ecosystems and their services in their national territory by 2014, assess the economic value of such services, and promote the integration of these values into account- ing and reporting systems at EU and national level by 2020’. The assistance of the European Commission is embodied in the work- ing group MAES (mapping and assessment of ecosystem services), 1 https://www.cbd.int/sp/targets/. 2 http://ec.europa.eu/environment/nature/biodiversity/comm2006/2020.htm. http://dx.doi.org/10.1016/j.ecolind.2015.10.023 1470-160X/© 2015 Elsevier Ltd. All rights reserved.