Lauriane Mouysset

From Population Viability Analysis to Coviability of Farmland Biodiversity and Agriculture

Substantial declines in farmland biodiversity have been reported in Europe for several decades. Agricultural changes have been identified as a main driver of these declines. Although different agrienvironmental schemes have been implemented, their positive effect on biodiversity is relatively unknown. This raises the question as to how to reconcile farming production and biodiversity conservation to operationalize a sustainable and multifunctional agriculture. We devised a bioeconomic model and conducted an analysis based on coviability of farmland biodiversity and agriculture. The coviability approach extended population viability analyses by including bioeconomic risk. Our model coupled stochastic dynamics of both biodiversity and farming land-uses selected at the microlevel with public policies at the macrolevel on the basis of financial incentives (taxes or subsidies) for land uses. The coviability approach made it possible for us to evaluate bioeconomic risks of these public incentives through the probability of satisfying a mix of biodiversity and economic constraints over time. We calibrated the model and applied it to a community of 34 common birds in metropolitan France at the small agricultural regions scale. We identified different public policies and scenarios with tolerable (0-0%) agroecological risk and modeled their outcomes up to 2050. Budgetary, economic, and ecological (based on Farmland Bird Index) constraints were essential to understanding the set of viable public policies. Our results suggest that some combinations of taxes on cereals and subsidies on grasslands could be relevant to develop a multifunctional agriculture. Moreover, the flexibility and multicriteria viewpoint underlying the coviability approach may help in the implementation of adaptive management.

Ecological-economic modelling for the sustainable management of biodiversity

Terrestrial and marine biodiversity provides the basis for both ecosystems functioning and numerous commodities or services that underpin human well-being. From several decades, alarming trends have been reported worldwide for both biodiversity and ecosystem services. Therefore the sustainable management of biodiversity requires a double viewpoint balancing ecological conservation with the welfare of human societies. Understanding the underlying trade-offs, synergies and interactions imposes the development of interdisciplinary researches and methods. In that respect, bio-economic or ecological economic modeling is likely to play a major role. The present paper intends to elicit the key features, strengths and challenges of bio-economic approaches especially in mathematical and computational terms. It first recall the main bio-economic methods, models and decisional instruments used in these types of analyses. Then the paper shows to what extent bio-economic sustainability lies between equilibrium, viability and optimality mathematical frameworks. It ends up by identifying new major challenges among which the operationalization of ecosystem based management, the precautionary principle and the implementation of governance are especially important.

Reconciling agriculture and biodiversity in European public policies: a bio-economic perspective

Agriculture has been identified as a major driver of the current significant changes in farmland biodiversity. Taking into account these environmental impacts, agriculture today aims at a more sustainable way of producing that would reconcile its economic and ecological functions. A new approach based on bio-economic modeling has been recently developed to explore different facets of such reconciliation and to understand how to promote sustainable agricultural public policies. In this paper, we review the contributions of such approach. The review shows that it is possible to reconcile agriculture and biodiversity with public policies, since it is possible to increase simultaneously the economic and ecological performances of agricultural landscapes compared to the current trends. However, it is not possible to optimize this reconciliation: The different criteria cannot be maximized simultaneously, and some trade-offs emerge between economic and ecological criteria in optimality. To go further, some bio-economic studies open new perspectives. For example, they suggest studying the society as a whole instead of focusing on the agricultural sector or going beyond the concept of optimality by stressing the idea of viability. In addition to reforming the current agricultural policies, deeper debates on the notion of sustainability have to be held.

Selection of Dynamic Models for Bird Populations in Farmlands

Agricultural changes have caused severe decline in the common bird communities in Europe. Mitigating this loss requires both understanding of and way to predict how agriculture affects biodiversity. The objective of this paper is to test the different dynamic models coupling bird abundances with farming land use. The agro-ecological calibration relies on 2002–2009 data for 34 bird species and 14 agricultural systems in 620 small agricultural regions of metropolitan France. The models are compared based on indicators of goodness-of-fit and predictive quality. The results highlight the relevance of systemic, functional, and mechanistic relationships between the agriculture and bird populations in both descriptive and predictive contexts. However, it seems that the best dynamic models to describe the past trends are not necessarily the most relevant to predict the future trends although there is a similar subset of five models that emerges in both cases. Ranking these different models depends on both the objective (describing or predicting) and the chosen functional level for the analysis (total community, functional groups or species).