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It is increasingly recognized that climate change will have a disproportionate impact on smallholder farmers, due to their dependence on agriculture for both livelihoods and food security, their often high levels of poverty, location in remote areas and marginal lands, and lack of access to technical support and credit. Consequently, across the world, governments are developing strong adaptation policies and plans to help smallholder farmers adapt to the increased frequency and intensity of extreme weather events and other aspects of climate change. One approach that holds great promise for smallholder farmers is the use of ecosystem-based adaptation- the use of ecosystem services and biodiversity as part of an overall adaptation strategy to help people adapt to the adverse effects of climate change. However, to date, there is little information available on what EbA options are available and feasible for farmers, how effective these are in reducing farmer vulnerability to extreme weather events and climate change, and what the opportunities and constraints are for scaling up these approaches. Using information from a detailed literature review, expert interviews, and a policy review, we will present an overview of the different types of ecosystem-based adaptation measures that are appropriate for smallholder coffee and maize/bean farmers in Central America, examine how effective these approaches are for reducing farmer vulnerability to extreme weather events, and discuss key technical, policy and financial constraints to broad scale adoption. Our study highlights the importance of systematically including Ecosystem-based adaptation in ongoing climate change policies, national adaptation plans and associated resource allocations, and the need for greater understanding of the specific mechanisms by which EbA practices deliver the ecosystem services on which people depend. (Texte intégral)

Ecosystem-based Adaptation (EbA) is the use of ecosystem services and biodiversity as part of an overall adaptation strategy to reduce the adverse impacts of climate change. It includes conserving, restoring and sustainably managing ecosystems to ensure the continued provision of services to people. The concept of EbA, by definition, includes both a focus on ecosystem services and a social component due to the emphasis on helping people to adapt to climate change. Recent studies indicate that ecosystem-based adaptation could be an important option for helping smallholder farmers adapt to climate change. In Central America, for example, EbA practices such as the use of shade coffee and other agroforestry systems, windbreaks, live fences, cover crops and conservation of on-farm riparian forests can help improve the resiliency of agricultural systems to climate change, while also ensuring the continued provision of key ecosystem services such as water provision, pollination and carbon sequestration. However, despite the potential of EbA to help farmers adapt to climate change, EbA options are often overlooked in adaptation planning. One key factor affecting the adoption of EbA practices is the knowledge held by local and national experts (including researchers, technicians, farm managers, and extensionists), who can provide recommendations about the options available to smallholder farmers. In order to better understand the extent to which local experts are familiar with EbA practices and are knowledgeable about the adaptation and other benefits they provide and to determine how their knowledge compares to the existing scientific literature, we conducted detailed interviews with over 100 local and national agricultural experts across the Central American region on the EbA options available for smallholder coffee and maize/bean farmers. At the same time, we conducted an extensive literature review (>300 publications) of all known agricultural practices that have been reported as potential adaptation options for these farmers, to better understand the current scientific knowledge on this regard. Our study indicates both scientific literature and national and local experts acknowledge the importance of the same kind of mechanisms providing adaptation benefits in EbA practices; such mechanisms include buffering the impact of extreme weather events, increasing agroecosystems resilience, buffering the impact of pests and diseases effects, and providing socioeconomic benefits, among others. Although the same practices were mentioned in the literature review and the experts' interviews, the practices are mentioned in different frequencies in both sources of knowledge for this study, which might be due to the fact that in the case of experts their knowledge and recommendations is adapted to the geographical area where they work, therefore, the frequency in which they mention practices is not identical to scientific literature. Our study suggests that knowledge from local and national experts might not be a limiting factor for the adoption of EbA practices, evidenced by the congruence between the experts' body of knowledge and the scientific literature. We finalize analyzing a set of constraints mentioned by experts as possible limiting factors for adoption, which include farmers' lack of funds, lack of technical assistance to farmers, lack of incentives, and socio-cultural factors related to reluctance to changing practices. (Texte intégral)

Mutualistic interactions involving pollination and ant-plant mutualistic networks typically feature tightly linked species grouped in modules. However, such modularity is infrequent in seed dispersal networks, presumably because research on those networks predominantly includes a single taxonomic animal group (e.g. birds). Herein, for the first time, we examine the pattern of interaction in a network that includes multiple taxonomic groups of seed dispersers, and the mechanisms underlying modularity. We found that the network was nested and modular, with five distinguishable modules. Our examination of the mechanisms underlying such modularity showed that plant and animal trait values were associated with specific modules but phylogenetic effect was limited. Thus, the pattern of interaction in this network is only partially explained by shared evolutionary history. We conclude that the observed modularity emerged by a combination of phylogenetic history and trait convergence of phylogenetically unrelated species, shaped by interactions with particular types of dispersal agents.