2 - PhD project

PhD in Ecology (spe. economic ecology) defended on 16 May 2012

Public policies facing biodiversity : bio-economic models and scenarios for a sustainable agriculture in France

Abstract - Global changes such as the climate change, the agriculture evolution or the urbanization, have exerted significant pressures on biodiversity (declines, extinctions, and biotic homogenizations). In this context, reconciling human activities with a sustainable biodiversity turns out as a main issue. To respond to this objective, the development of bio-economic analysis appears as an interesting perspective for public policies facing biodiversity. However the agri-environmental policies have not yet been able to provide a relevant management of biodiversity. Based on a bio-economic process, this PhD intends to contribute to the debate on public policies facing the challenge of a sustainable management of agriculture and biodiversity.

The systemic models developed in this work combine both ecologic and economic dynamics through land-use variables at the small agricultural area scale across the whole France. In our case, biodiversity is perceived as a community of 34 common birds, avoiding an emblematic species-based approach. Calibration of the models is based on agri-economic and ecological time series from 2001 to 2009. Different scenarios are generated up to 2050 and their bio-economic performances are compared through a set of indicators, avoiding the problem of biodiversity monetization. A focus on the choice of these indicators has been driven to characterize correctly the status of communities. In particular, different aspects of the sustainability are explored by combining cost-effectiveness and co-viability approaches.

This study shows that it is possible to improve simultaneously ecological and economic performances in comparison to the current trends. In the one hand, economic incentives at the macro-economic scale guide directly the farmers’ choices towards more biodiversity-friendly activities. In the other hand, diversification mechanisms, in response to economic risk, have also a positive influence on the bio-economic performances. However, it appears difficult to maximize simultaneously economic and ecological objectives. The PhD explores several options to overcome this bio-economic trade-off. In particular, an analysis based on public costs suggests that the integration of ecological objectives in the public policies generates a double dividend. Finally, in an uncertain context, the approach of co-viability allows us to identify scenarios leading to a multi-functional agriculture that remains fair through generations.

Extending these bio-economic approaches towards the concept of ecosystemic services should bring further insight into the design of public policies achieving a sustainable biodiversity.

Key-words - Bio-economics, Biodiversity, Agriculture, Modelling, Cost-effectiveness, Viability, Bird, Land-use, Indicator, Risk.