Les enjeux de l’équivalence écologique pour la conception et le dimensionnement de mesures compensatoires d’impacts sur la biodiversité et les milieux naturels,

L’évolution du contexte réglementaire a renforcé l’obligation de compenser " en nature " les impacts sur la biodiversité qui n’ont pas pu être évités ou réduits. Dans ce contexte, l’évaluation de l’équivalence entre les pertes causées par ces impacts et les gains de biodiversité attendus des actions de compensation suscite des questions scientifiques et techniques quant aux concepts et connaissances à mobiliser et aux méthodes d’évaluation à développer et mettre en ½uvre. On y trouve en particulier l'identification des éléments de biodiversité à considérer, le développement d’indicateurs appropriés permettant de comparer pertes et gains, la sélection d’un état de référence pour le calcul des pertes et gains, et la prise en compte des dynamiques écologiques et des incertitudes dans l’évaluation du devenir des sites de compensation. Par ces questions, l'équivalence écologique donne un cadre de raisonnement explicite à la conception et au dimensionnement de la compensation qui est appropriable par chacun des acteurs concernés. / Since 2007 France has seen a radical strengthening of its legislation concerning the mitigation of development impacts on biodiversity and ecosystems. Under pressure from the European Union and as an outcome of a national consultative process called the “Grenelle de l’Environnement”, the scope of the mitigation hierarchy of avoiding, reducing and offsetting impacts of plans, programs and projects has been expanded. It now includes stronger requirements in terms of monitoring and effective implementation. These changes – which have strong financial and legal implications for developers - have revealed the lack of technical guidelines for designing and sizing offsets. Assessing the ecological equivalence between losses caused by impacts and the gains expected from offset actions raises scientific and technical issues that remain unresolved. These include the identification of relevant components of biodiversity, the development of appropriate indicators, the identification of reference states and the incorporation of ecological dynamics and uncertainties into offset design and sizing

How would farmers in the French Alps adapt their systems to different drought and socio-economic context scenarios?

International audienceThe French Alps are considered as an area that is particularly vulnerable to climate change. Several droughts have already occurred since 2003. In order to assess the ability of farming systems to adapt to future drought events, we developed prospective scenarios combining different climatic and socio-economic contexts. Four scenarios were defined based on (i) prospective studies conducted at national and international levels, and (ii) a participatory approach with various stakeholders to transcribe these scenarios at a local level. Farmers and shepherds in the Vercors and Oisans massifs were surveyed in order to understand how they had reacted to previous droughts, and how they would plan to react to our scenarios. Results show first that the farmers would strive to continue their activity in each scenario, taking advantage of the flexibility of their farming systems, as in previous years. However, in the most pessimistic climatic scenario, they would also decrease the size of their herds. Depending on the socio-economic hypothesis, they would adopt farm structural changes (farm processing activities, direct selling, etc.), or look for part-time non-agricultural jobs. Three types of strategies were identified, depending on the farmers' objectives and adjustments. Finally, public policies to accompany these changes are considered

The Global Forest Transition as a Human Affair

Forests across the world stand at a crossroads where climate and land-use changes are shaping their future. Despite demonstrations of political will and global efforts, forest loss, fragmentation, and degradation continue unabated. No clear evidence exists to suggest that these initiatives are working. A key reason for this apparent ineffectiveness could lie in the failure to recognize the agency of all stakeholders involved. Landscapes do not happen. We shape them. Forest transitions are social and behavioral before they are ecological. Decision makers need to integrate better representations of people’s agency in their mental models. A possible pathway to overcome this barrier involves eliciting mental models behind policy decisions to allow better representation of human agency, changing perspectives to better understand divergent points of view, and refining strategies through explicit theories of change. Games can help decision makers in all of these tasks

Global no net loss of natural ecosystems

A global goal of no net loss of natural ecosystems or better has recently been proposed, but such a goal would require equitable translation to country-level contributions. Given the wide variation in ecosystem depletion, these could vary from net gain (for countries where restoration is needed), to managed net loss (in rare circumstances where natural ecosystems remain extensive and human development imperative is greatest). National contributions and international support for implementation also must consider non-area targets factors such as the capacity to conserve and the imperative for human development

The many meanings of No Net Loss in environmental policy

‘No net loss’ is a buzz phrase in environmental policy. Applied to a multitude of environmental targets such as biodiversity, wetlands and land productive capacity, no net loss (NNL) and related goals have been adopted by multiple countries and organizations, but these goals often lack clear reference scenarios: no net loss compared to what? Here, we examine policies with NNL and related goals, and identify three main forms of reference scenario. We categorize NNL policies as relating either to overarching policy goals, or to responses to specific impacts. We explore how to resolve conflicts between overarching and impact-specific NNL policies, and improve transparency about what NNL-type policies are actually designed to achieve

Local conditions and policy design determine whether ecological compensation can achieve No Net Loss goals.

Funder: Science for Nature and People Partnership Australian Research Council Discovery Early Career Research Award (DE170100684) Australian Research Council Future Fellowship (FT140100516) The Australian Government’s National Environmental Science Program through the Threatened Species Recovery Hub Agence Française de Développement Fonds Français pour l'environnement Mondial Mava FoundationFunder: Science for Nature and People Partnership Australian Research Council Future Fellowship FT140100516 National Environmental Science Program's Threatened Species Recovery HubMany nations use ecological compensation policies to address negative impacts of development projects and achieve No Net Loss (NNL) of biodiversity and ecosystem services. Yet, failures are widely reported. We use spatial simulation models to quantify potential net impacts of alternative compensation policies on biodiversity (indicated by native vegetation) and two ecosystem services (carbon storage, sediment retention) across four case studies (in Australia, Brazil, Indonesia, Mozambique). No policy achieves NNL of biodiversity in any case study. Two factors limit their potential success: the land available for compensation (existing vegetation to protect or cleared land to restore), and expected counterfactual biodiversity losses (unregulated vegetation clearing). Compensation also fails to slow regional biodiversity declines because policies regulate only a subset of sectors, and expanding policy scope requires more land than is available for compensation activities. Avoidance of impacts remains essential in achieving NNL goals, particularly once opportunities for compensation are exhausted

Great Apes and Biodiversity Offset Projects in Africa: The Case for National Offset Strategies

The development and private sectors are increasingly considering “biodiversity offsets” as a strategy to compensate for their negative impacts on biodiversity, including impacts on great apes and their habitats in Africa. In the absence of national offset policies in sub-Saharan Africa, offset design and implementation are guided by company internal standards, lending bank standards or international best practice principles. We examine four projects in Africa that are seeking to compensate for their negative impacts on great ape populations. Our assessment of these projects reveals that not all apply or implement best practices, and that there is little standardization in the methods used to measure losses and gains in species numbers. Even if they were to follow currently accepted best-practice principles, we find that these actions may still fail to contribute to conservation objectives over the long term. We advocate for an alternative approach in which biodiversity offset and compensation projects are designed and implemented as part of a National Offset Strategy that (1) takes into account the cumulative impacts of development in individual countries, (2) identifies priority offset sites, (3) promotes aggregated offsets, and (4) integrates biodiversity offset and compensation projects with national biodiversity conservation objectives. We also propose supplementary principles necessary for biodiversity offsets to contribute to great ape conservation in Africa. Caution should still be exercised, however, with regard to offsets until further field-based evidence of their effectiveness is available

Trait modality distribution of aquatic macrofauna communities as explained by pesticides and water chemistry

Analyzing functional species’ characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2–4 % to pesticides, and for 3–11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10646-016-1671-5) contains supplementary material, which is available to authorized users