The circulation of seed among farmers is central to agrobiodiversity conservation and dynamics. Agrobiodiversity, the diversity of agricultural systems from genes to varieties and crop species, from farming methods to landscape composition, is part of humanity's cultural heritage. Whereas agrobiodiversity conservation has received much attention from researchers and policy makers over the last decades, the methods available to study the role of seed exchange networks in preserving crop biodiversity have only recently begun to be considered. In this overview, we present key concepts, methods, and challenges to better understand seed exchange networks so as to improve the chances that traditional crop varieties (landraces) will be preserved and used sustainably around the world. The available literature suggests that there is insufficient knowledge about the social, cultural, and methodological dimensions of environmental change, including how seed exchange networks will cope with changes in climates, socio-economic factors, and family structures that have supported seed exchange systems to date. Methods available to study the role of seed exchange networks in the preservation and adaptation of crop specific and genetic diversity range from meta-analysis to modelling, from participatory approaches to the development of bio-indicators, from genetic to biogeographical studies, from anthropological and ethnographic research to the use of network theory. We advocate a diversity of approaches, so as to foster the creation of robust and policy-relevant knowledge. Open challenges in the study of the role of seed exchange networks in biodiversity conservation include the development of methods to (i) enhance farmers' participation to decision-making in agro-ecosystems, (ii) integrate ex situ and in situ approaches, (iii) achieve interdisciplinary research collaboration between social and natural scientists, and (iv) use network analysis as a conceptual framework to bridge boundaries among researchers, farmers and policy makers, as well as other stakeholders. (Résumé d'auteur

Several decades of frustrated attempts to prevent fires in the Brazilian Savanna (Cerrado) have led to deleterious ecological and management consequences. In 2014, the first Integrated Fire Management (IFM) programme was launched in three protected areas (PAs). The IFM programme considers local practices, ecological information, management options and aims to create landscape mosaics of different fire histories to conserve biodiversity, reduce the prevalence of late‐dry season (LDS) wildfires, protect fire‐sensitive vegetation and reduce conflicts between PA managers and local communities. The first 3 years of imposed fire management regimes led to 40%–57% reduction in LDS fires, improved dialogue between researchers, managers and local communities, generating fire management learning communities. Synthesis and applications. This Integrated Fire Management programme represents a major advance in Cerrado management and conservation, by actively managing fires and decreasing the proportion of areas burnt by late‐dry season wildfires. It can contribute to PAs’ management in the Cerrado and other South American fire‐prone ecosystems. Long‐term monitoring and research are essential to understand the ecological implications and to improve fire management practices.

Wildfires continue to cause damage to property, livelihoods and environments around the world. Acknowledging that dealing with wildfires has to go beyond fire-fighting, governments in countries with fireprone ecosystems have begun to recognize the multiple perspectives of landscape burning and the need to engage with local communities and their practices. In this perspective, we outline the experiences of Brazil and Venezuela, two countries where fire management has been highly contested, but where there have been recent advances in fire management approaches. Success of these new initiatives have been measured by the reduction in wildfire extent through prescribed burning, and the opening of a dialogue on fire management between government agencies and local communities. Yet, it is clear that further developments in community participation need to take place in order to avoid the appropriation of local knowledge systems by institutions, and to better reflect more equitable fire governance.

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Anthropogenic fire has long shaped landscapes and livelihoods in South American savanna environments. With the growing recognition of the failures of fire suppression policies and the relevance of local peoples’ practices, the Brazilian and Venezuelan governments have begun to shift to fire management policies in savanna ecosystems. Using case studies from protected areas in Cerrado and Gran Sabana, and results from two multi‐stakeholder meetings held in Parupa (Venezuela) and Brasilia (Brazil), we identify advances, resistances and challenges to inter‐cultural fire management in both countries. We show that the two regions host pioneer experiences in collaborative research based on improved dialogue and knowledge exchanges between scientists, institutions, Indigenous and local communities as well as fire management implementation including “controlled” and “prescribed” burnings. However, in some places, narrow understanding of the complexity and historical dynamics of local fire practices and the strong resistance to recognise the value of traditional fire knowledge might restrain effective participation of local communities. We argue that more collaborative research is necessary to support community owned solutions for intercultural and participative fire management in changing environmental and socio‐cultural contexts.

The use of fire by cattle ranchers is a major source of conflict between conservationists and local communities in tropical savannas. We evaluate the role of traditional pastoral management in wildfire prevention in two Protected Areas within the Brazilian savanna. Finegrain field data from transect walks and interviews were combined with geospatial data at landscape scale to compare fire regimes in community-managed areas with those in governmental-managed areas. Local pastoral management creates seasonal mosaic patterns of burnings performed for productive activities and for deliberate landscape management, i.e., to protect fire-sensitive vegetation and avoid wildfires. Whereas government-managed areas were affected by large biennial late dry season wildfires, community-managed areas with a regular fire regime suffered less damage. These systems are under threat and poorly understood by researchers and environmental managers. In order to improve fire management in tropical savannas, greater understanding of pastoral management practices and their spatiotemporal dimensions is required.

IIResumo: As regiões do Médio e Alto Rio Negro, apesar de serem isoladas da malha de comunicação terrestre e das frentes de colonização, caracterizam-se por uma articulação cada vez mais forte entre a área florestal, a das comunidades, e a urbana, ou seja, as pequenas cidades ribeirinhas. Esta complementaridade, temporária ou definitiva, se traduz por uma expansão da agricultura periurbana. Propomos uma abordagem comparativa da diversidade agrícola entre o urbano e o florestal. Analisamos as relações entre formas de manejo dos espaços cultivados (superfícies, ciclo de uso e práticas), plantas cultivadas e redes sociais envolvidas no acesso aos recursos fitogenéticos. A análise mostra uma recomposição dos sistemas agrícolas com a permanência de uma alta diversidade agrícola, porém marcada por uma maior vulnerabilidade do sistema em decorrência da diminuição do tempo de pousio e da diminuição da força de trabalho disponível. No contexto urbano, as estratégias tradicionais de manejo dos recursos agrícolas se combinam a um outro objetivo, o do acesso à terra. A análise aponta para a necessidade de uma reflexão sistémica sobre as possíveis formas de conservação deste patrimônio biocultural.Palavras-chave: Amazônia. Agrobiodiversidade. Dinâmicas rurais urbanas. Etnobotânica. Abstract: Despite its isolation from land communications networks and colonization frontiers, the regions of the Upper and MiddleNegro River are characterized by increasing connectivity between rural or forest areas, pertaining to communities, and urban areas, i.e. small towns along the river. Population movement between these two poles, on a temporary or permanent basis, results in expanded periurban agriculture, in the context of new social and ecological arrangements. A comparative approach is proposed to cultivated plants diversity, based on a sample of 14 and 18 families in these urban and forest contexts. Relations among the diversity of managed spaces, biological diversity and social networks involved in access to phytogenetic resources were analyzed. The analysis shows a recomposition of agricultural systems with high crop diversity, at times higher than in the context of forests, albeit subject to more system vulnerability due to reduced fallow periods and available manual labor. In urban areas, traditional agricultural resource management strategies are combined with another objective, farmed lands access. This analysis also points out the need for reflection about the conservation of a biocultural heritage.

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