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Ecological intensification is a new concept in agriculture that addresses the double challenge of maintaining a level of production sufficient to support needs of human populations and respecting the environment in order to conserve the natural world and human quality of life. This article adapts this concept to fish farming using agroecological principles and the ecosystem services framework. The method was developed from the study of published literature and applications at four study sites chosen for their differences in production intensity: polyculture ponds in France, integrated pig and pond polyculture in Brazil, the culture of striped catfish in Indonesia and a recirculating salmon aquaculture system in France. The study of stakeholders' perceptions of ecosystem services combined with environmental assessment through Life Cycle Assessment and Emergy accounting allowed development of an assessment tool that was used as a basis for co-building evolution scenarios. From this experience, ecological intensifica-tion of aquaculture was defined as the use of ecological processes and functions to increase productivity, strengthen ecosystem services and decrease disservices. It is based on aquaecosystem and biodiversity management and the use of local and traditional knowledge. Expected consequences for farming systems consist of greater autonomy, efficiency and better integration into their surrounding territories. Ecological intensification requires territorial governance and helps improve it from a sustainable development perspective. International audience

We report above-ground biomass (AGB), basal area, stemdensity and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries. Mean AGB is 395.7 Mg dry mass ha-1 (95% CI: 14.3), substantially higher than Amazonian values, with the Congo Basin and contiguous forest region attaining AGB values (429 Mg ha-1) similar to those of Bornean forests, and significantly greater than East or West African forests. AGB therefore appears generally higher in palaeo- comparedwithneotropical forests.However, mean stem density is low(426±11 stems ha-1 greater than or equal to 100 mm diameter) compared with both Amazonian and Bornean forests (cf. approx. 600) and is the signature structural feature of African tropical forests. While spatial autocorrelation complicates analyses, AGB shows a positive relationship with rainfall in the driest nine months of the year, and an opposite association with the wettest three months of the year; a negative relationship with temperature; positive relationship with clay-rich soils; and negative relationshipswith C:Nratio (suggesting a positive soil phosphorus- AGB relationship), and soil fertility computed as the sum of base cations. The results indicate that AGB is mediated by both climate and soils, and suggest that the AGB of African closed-canopy tropical forests may be particularly sensitive to future precipitation and temperature changes. © 2013 The Authors. info:eu-repo/semantics/published SCOPUS: ar.j 0

Abstract - The study of natural ecosystems and experiments using mixtures of plant species demonstrates that both species and genetic diversity generally promote ecosystem functioning. Therefore, mixing crop varieties is a promising alternative practice to transform modern high-input agriculture that is associated with a drastic reduction of within-field crop genetic diversity and is widely recognized as unsustainable. Here, we review the effects of mixtures of varieties on ecosystem functioning, and their underlying ecological mechanisms, as studied in ecology and agronomy, and outline how this knowledge can help designing more efficient mixtures. We recommend the development of two complementary strategies to optimize variety mixtures by fostering the ecological mechanisms leading to a positive relationship between biodiversity and ecosystem functioning and its stability through time, i.e., sampling and complementarity effects. (1) In the “trait-blind” approach, the design of high-performance mixtures is based on estimations of the mixing abilities of varieties. While this approach is operational because it does not require detailed trait knowledge, it relies on heavy experimental designs to evaluate mixing ability. (2) The trait-based approach is particularly efficient to design mixtures of varieties to provide particular baskets of services but requires building databases of traits for crop varieties and documenting the relations between traits and services. The performance of mixtures requires eventually to be evaluated in real economic, social, and agronomic contexts. We conclude that the need of a multifunctional low-input agriculture strongly increases the attractiveness of mixtures but that new breeding approaches are required to create varieties with higher mixing abilities, to foster complementarity and selection effects through an increase in the variance of relevant traits and to explore new combinations of trait values. International audience

Despite a long history of confrontation between forest agencies and forest people, “indigenous” or “local” practices are increasingly considered as a viable alternative of forest management. This paper is a synthesis derived from various long-term research programs carried out by the authors in Southeast Asia and Africa on forests managed by farmers. These researches looked at local practices and underlying science, including their social, political, and symbolic dimensions. They also addressed evolutionary trends and driving forces, as well as potential and limits for forest conservation and development, mitigation of deforestation, biodiversity conservation, and poverty alleviation in a context of global environmental, political, and social change. We discuss how forest management by local communities, contrary to the unified models of professional forest management, exhibits a high historical and geographical diversity. The analysis we draw from the various examples we studied reveals several invariants, which allows proposing the unifying paradigm of “domestic forest.” The first universal feature concerns the local managers themselves, who are, in their vast majority, farmers. Management practices range from local interventions in the forest ecosystem, to more intensive types of forest culture, and ultimately to permanent forest plantation. But in all cases, forest management is closely integrated with agriculture. The second universal feature concerns the conceptual continuity of planted forests with the natural forest, in matters of vegetation's structure and composition as well as economic traits and ecosystem services. The resulting forest is uneven-aged, composed of several strata, harboring a large diversity of species, and producing a wide range of products, with timber seldom being the dominant one. The term “domestic forest” aims at highlighting the close relationship the domestication process establishes between a specific human group, including its elementary units, the “domestic units,” and the forest, transformed and managed to fulfill the needs of that group. The domestic forest paradigm calls for the integration into forest science of a new concept of land management in which production and conservation are compatible, and in which there is no choice to be made between people and nature. It does not aim at contesting the value of conventional forest science, but it proposes domestic forests as a new scientific domain, for the combined benefit of forest science and of forest people. It does not contest the value of conventional forest management models, but pushes towards more equitable relations between forest agencies and farmers managing forest resources on their own lands. International audience A-07-26

Managing complex landscape mosaics in areas dominated by poverty often requires addressing conflicting objectives and managing trade-offs, such as that between maintaining/enhancing ecological functions and improving livelihoods. Laos, like many other developing countries dependent on agriculture and natural resources for the subsistence of a mostly rural population, has used land use planning (LUP) as a core policy instrument to achieve sustainable development. However, previous reviews of LUP implementation showed large discrepancies between policies and practices and between the intended goals and actual outcomes. There is a need for increased participation, improved integration of scales, harmonization of superimposed plans, and enhanced coordination between implementing agencies and other stakeholders. Consequently, former normative approaches to LUP have been gradually replaced (at least on paper) by a new paradigm. Participatory land use planning (PLUP) has recently become a central element of donor-supported programs in developing countries. However, despite the good intentions of PLUP principles, implementation remains entangled with confused practical issues that compromise effective participation. As an alternative to complex, technologically sophisticated LUP models that local stakeholders cannot use or replicate, a communication platform supporting negotiations among multiple stakeholder groups was tested in a village cluster in Luang Prabang Province in northern Laos. This innovative approach, based on a combination of role-playing games, participatory 3D modeling, GIS, and socioeconomic and environmental impact assessment, allows stakeholders to collectively explore the consequences of land use decisions and choose between alternative future landscapes.

ABSTRACT Indonesian rubber agroforests—smallholders' plantations combining a large number of perennial species—are known to provide a number of environmental services. They produce natural rubber as well as various secondary products for cash or home consumption. We estimated the quantities of the various products, the proportions harvested, consumed by the farmer's family or sold, and the cash income generated. Quantities and prices were estimated based on plot surveys and interviews. Economic models of various kinds of agroforest were generated, and the impact of the tree composition on the income was evaluated based on these models. Results show that agroforest products are quite well valued, but that return to land remains low. An enrichment of agroforests in Parkia speciosa Hassk could improve their productivity and help farmers cope with economic crises