Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network ( Rede Amazônia Sustentável , 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.

[1] Do the influences of river breezes or other mesoscale effects lead to a systematic river proximity bias in Amazon rainfall data? We analyzed rainfall for a network of 38 rain gauges located near the confluence of the Tapajós and Amazon rivers in the eastern Amazon Basin. Tipping bucket rain gauges worked adequately in the Amazon rainfall regime, but careful field calibration and comparison with collocated conventional rain gauges were essential to incorporate daily totals from our array into regional maps. Stations very near the large rivers miss the afternoon convective rain, as expected if a river breeze promotes subsidence over the river, but paradoxically, this deficiency is more than compensated by additional nocturnal rainfall at these locations. The NOAA Climate Prediction Center (CPC) Morphing technique (CMORPH) passive infrared inferred rainfall data do an adequate job of describing medium scale variability in this region, but some localized breeze effects are not resolved at 0.25°resolution. For areas inland from the rivers, nocturnal rainfall contributes less than half of total precipitation. A large-scale rainfall increase just to the west of Santarém manifests itself locally as a 'tongue' of enhanced rain from along the wide area of open water at the Tapajós-Amazon confluence. The Amazon River breeze circulation affects rainfall more than does the Tapajós breeze, which moves contrary to the predominant wind. East of the riverbank, the effects of the Tapajós breeze extend only a few kilometers inland. Rainfall increases to the north of the Amazon, possibly the result of uplift over elevated terrain. Dry season rainfall increases by up to 30% going away from the Amazon River, as would be expected given breeze-induced subsidence over the river.

Organic matter plays an important role in many soil properties, and for that reason it is necessary to identify management systems which maintain or increase its concentrations. The aim of the present study was to determine the quality and quantity of organic C in different compartments of the soil fraction in different Amazonian ecosystems. The soil organic matter (FSOM) was fractionated and soil C stocks were estimated in primary forest (PF), pasture (P), secondary succession (SS) and an agroforestry system (AFS).

The Brazil nut is considered one of the noblest trees of the Amazon biome and contains social, ecologic and economic importance to this region. The study of the spatial variance of the edaphic properties in native nut trees can direct future researches about more efficient samplings. The Geostatistics is the methodology utilized for this type of study, once that it considers the structural and random characteristics of a variable spatially distributed. This work sought to get a higher knowledge about the distribution of the nutrients in the soil, verifying the relationship with the occurrence of this species, to thereby provide subsidies to future forest management and maintenance/enlargement of the productivity in these areas. The soil samples were collected from 30 × 30 m on the line, in all of the lines in part of the study, totaling 60 samples. All of the points were georeferenced. The preparation of the samples for the sample preparation for the chemical analysis and the methods and calculations to determine the physicochemical variables studied were described by Nogueira and Souza (2005). The statistical and geostatistical analysis were conducted using the R computational environment, version 3.2.2. Most of the studied variables presented defined level. For the physical variables, there was predominance of the adjustment to the model of the gaussian variogram, follower by the spherical model. In the case of the chemical variables, there were two occurrences for each adjustment model (spherical, exponential and gaussian). The variables that best presented spatial relation with the occurrence of Brazil nut trees were the silt, clay, macroporosity, pH, phosphorus, zinc and copper.

The Tapajós National Forest (FLONA Tapajós) has 600,000 hectares of protected forest, and is situated 50 km south of the city of Santarém, Pará, Brazil, a port city of 250,000 inhabitants that is located at the confluence of the Tapajós and Amazon Rivers. There is a lot of farmland in the region, which offers many opportunities to study changes in land use. Selective wood harvesting is one type of land use that is particularly important to the economy of Santarém. Wet and dry deposition of organic material can be an important source of nutrients for plants, and this is especially true when the soil is poor, which is the case in Santarém-Belterra plateau region, the study area of this research. In this region, the natural atmospheric deposition of nutrients is often enhanced by the burning of biomass, which releases a large part of the above-ground biomass nutrients into the atmosphere. The objectives of this study were: 1-estimate the total wet deposition via direct precipitation and through the canopy, including dry deposition; 2-verify potential sources of nutrients found in the total wet deposition and dry deposition; and 3-investigate the effects of coverage vegetation on nutrient content in precipitation and throughfall. The study was conducted in FLONA Tapajós at km 67 of Santarém-Cuiabá Highway, south of the city of Santarém. The study area consisted of a portion of 100 x 100 m transects divided into 10 x 10 m plots. The area was located next to a meteorological tower 65 m tall that measures various climate parameters such as rainfall, wind speed and direction, solar radiation, temperature and humidity, among others. Direct precipitation (PD) and internal precipitation (IP) collectors consisted of 2 L polyethylene bottles with a 115 mm diameter funnel. Samples were collected weekly from April 2003 to March 2006. The volume of the sample was measured individually for each collector (25 traps for internal precipitation and 4 for direct precipitation). The conclusions that can be drawn from this study are: 1-the dry season has the highest variation Palavras-chave: ciclagem de nutrientes, floresta tropical, região amazônica.

Twenty female Murrah buffaloes between four and five years old were randomly distributed into two groups (traditional system - TS and silvopastoral system - SPS) with 10 animals each and an average weight of 377.78 kg and 356.10 kg, respectively, for the TS and the SPS. The TS had a management regime with no canopy cover and no shade coverage over the drinking and feeding troughs. In the SPS, Racosperma mangium (Fabaceae) trees were used to provide shade, with an estimated 10% shading. The physiological variables studied were rectal temperature and respiratory frequency measured every three days from 6 to 7 AM and from 12 to 1 PM. The following environmental indices were calculated: Temperature Humidity Index (THI), Black Globe Humidity Comfort Index (BGHI), and Benezra’s Index of Adaptability (BIA). The THI values were high in both management systems, between 76.27 and 86.73, higher than the limit of comfort level for buffaloes, which is 75. The maximum values of BGHI for the afternoon were 92.0 and 87.62, for TS and SPS, respectively, and the maximum values of BIA for the afternoon were 4.4 and 3.8, for TS and SPS respectively, which were higher than the critical level of adaptability and represented an uncomfortable condition that causes a reduction in animal performance. It was concluded that the silvopastoral management system is more efficient in terms of animal comfort for the female buffaloes as a result of the shade that provides a more amenable microclimate.

The objective of this study was to systematize a method that describes the dynamic processes that exist in space and time related to the production chain of the ceramic industry production center in Iranduba, Amazonas, Brazil, through the use of a mandala. A map of possible conditioning factors that can be characterized as links or problems related to the production chain was constructed, and this consisted of seven variables subdivided into three levels that stratify the descriptive steps of the processes of the production chain. A mandala was constructed in order to describe historical aspects of the ceramic industry production center in Iranduba, as well as to integrate biophysical and economic variables such as soil climate, energy sources used in the ceramic kilns, economic and financial variables, and specific characteristics of the ceramic industry production center. This method allowed for delineation of productive chain influences with the goal of improving the processes spatially and temporally. The results demonstrate that the structure of this method based on a mandala allows for an integral and systematic vision of these processes. It is therefore inferred that this is a practical tool which is integrated for making adjustments and new inclusions of techniques and procedures, remodeling the conditioning variables of production chains such as the one of the ceramic industry production center in Iranduba. The mandala is a tool that adjusts itself in time and space in a flexible way due to its capacity for interactive analysis in the construction of technical and scientific knowledge and dynamic and sustainable processes.

Afforestation with Eucalyptus species is increasing in Brazil, but there is little information on the impacts of intensively managed short-rotation forestry on soil aggregate dynamics and labile organic matter fractions in these tropical ecosystems. This study investigated soil aggregate dynamics in a clay and sandy soil, each with a Eucalyptus plantation and an adjacent primary forest. It is shown that silviculture alters the processes of soil aggregate formation on both soil types. Micro-aggregates at 0-20 cm depth in the planted clay soil were 40% greater in mass than under native forest, and C and N were reduced by 87 and 75%, respectively. In plantations with a sandy soil, micro-aggregates had equal mass compared with native forest, but increased in C and N by 20 and 67%, respectively. The results from the sandy soil indicate that C and N increased in micro-aggregates following afforestation. Macro-organic matter fractions separated by density had lower mass, C, and N concentrations, and higher C:N ratios only in lower soil profiles, with native forest having greater values in all comparisons with light and medium fractions. The differences in micro-aggregate C and N and in the light and medium macro-organic matter fractions between the upper and lower soil profiles in both soils, indicate that silvicultural management had contrasting effects on different soil textures and at different depths. Increased micro-aggregate protection of C and N in the sandy plantation soil could negatively affect long-term nutrient cycling although the quantity and quality of light and medium macro-organic matter fractions did not change between plantation and native forest in the upper soil profile; this indicates that labile OM availability and quality had not been diminished in plantation soils at this depth.