A social and ecological assessment of tropical land uses at multiple scales: the Sustainable Amazon Network

Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazonia Sustentavel, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far.Keywords: Social–ecological systems, Tropical forests, Land use, Interdisciplinary research, Sustainability, Trade-off

Dinâmica do amônio e nitrato em solos consorciados com plantios de Paricá (Schizolobium Amazonicum) em Aurora do Pará, Pará

To obtain knowledge of the dynamics of nitrogen in soil in the forms of mineral-N: ammonium and nitrate from 3 different areas cultivated with paricá, paricá x freijó (PF), mahogany x paricá (PM), paricá x curauá x freijó (PCF) and secondary forest, was estimated rates of net mineralization and nitrification, stocks of carbon and nitrogen, pH, urease, basal respiration and physical parameters (density and total porosity). The study was conducted in northeastern Para in the city of Aurora do Para, in the farm business Tramontina SA, in October and November of 2007, representing the dry season, while January and march representing the rainy season. In all areas of the farm cultivated samples for chemical and physical analysis were taken at depths of 0-10, 10-20 and 20-30 cm. For net mineralization of the highest values occurred in the dry season, this result was observed for all areas of cultive. For net nitrification of the highest values occurred in October 2007 in the areas of secondary forest and paricá x curauá x freijó and the month of March in the areas of mahogany x paricá (PM) and paricá x freijó (PF). The values for the rates of net nitrification showed that there was significant interaction between treatment and season. The values of carbon stocks for all areas in the dry season varied from 11-17 Mg/ha and in the rainy season of 15-25 Mg/ha. The values for the storage of nitrogen varied from 0,78-1,80 Mg/ha in the dry season and 0,76-1,47 Mg/ha in the rainy season. The relation C/N for all systems was around 15/1 indicating a rapid process of decomposition of organic matter in soils.Com o objetivo de obter conhecimento da dinâmica do nitrogênio em solo sob as formas de N-mineral: amônio e nitrato de 3 diferentes áreas cultivadas com o paricá, paricá x freijó (PF), paricá x mogno (PM), paricá x curauá x freijó (PCF) e floresta secundária, foi avaliado as taxas líquidas de mineralização e nitrificação, estoques de carbono e nitrogênio, pH, urease, respiração basal e parâmetros físicos (densidade e porosidade total). O estudo foi realizado no nordeste paraense no município de Aurora do Pará, na fazenda da empresa Tramontina, S.A, nos meses de outubro e novembro de 2007, representando o período seco, e janeiro e março de 2008 representando o período chuvoso. Nas duas áreas cultivadas da fazenda e na floresta secundária as amostras para as análises química e física foram retiradas nas profundidades de 0-10, 10-20 e 20-30 cm. Para as taxas líquidas de mineralização os maiores valores ocorreram na estação seca, este resultado foi observado para todas as áreas de cultivo. Para as taxas líquidas de nitrificação os maiores valores ocorreram no mês de outubro de 2007 nas áreas de capoeira e paricá x curauá x freijó e no mês de março nas áreas de Paricá x mogno (PM) e paricá x freijó (PF). Os valores para as taxas líquidas de nitrificação mostram que ocorreu interação significativa entre tratamento e estação. Os valores do estoque de carbono para todas as áreas na estação seca variaram de 11-17 Mg/ha e na estação chuvosa de 15-25 Mg/ha. Os valores para o estoque de nitrogênio variaram de 0,78-1,80 Mg/ha na estação seca e de 0,76-1,47 Mg/ha na estação chuvosa. A relação C/N para todos os sistemas ficou por volta de 15/1 indicando um rápido processo de decomposição da matéria orgânica nesses solos

A social and ecological assessment of tropical land uses at multiple scales:the Sustainable Amazon Network

Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazonia Sustentavel, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far