Analysing interactions among the sustainable development goals: findings and emerging issues from local and global studies.

The topic of SDG interactions is a relatively new research area with many knowledge gaps. Some of these gaps are addressed in this summary of a Special Feature of Sustainability Science, including new findings and emerging issues on (1) the characteristics of SDG interactions; (2) methods/methodology to analyse these interactions; and (3) the elaboration of drivers that influence SDG synergies. The importance of scale is clear in two emerging issues. First, there is evidence of a disconnect between national planning for SDGs and their implementation at the local scale which is leading to SDG trade-offs between these scales. Second, the concept of a "critical transition zone" is introduced where SDG trade-offs pose a particular challenge to SDG implementation. These are areas (e.g., peri-urban and forest margin areas in the Global South) undergoing rapid biophysical and/or socio-economic changes and inhabited by populations especially vulnerable to these changes. While trade-offs occur among the SDGs, there are also many examples of synergies which provide opportunities for advancing multiple goals. To distinguish between synergies and the actions that exploit them, the term "synergy driver" is introduced to refer to policies and measures that positively advance two or more goals. Several examples of synergy drivers are presented, including sustainable global supply chains, people-centred early warning systems, and joint conservation-public health programmes. To make synergy drivers relevant to the broader policy community, the research community (working with stakeholders) should first consolidate knowledge about these drivers and then evaluate their effectiveness/applicability to different policy settings.

Nut Production in Bertholletia excelsa across a Logged Forest Mosaic: Implications for Multiple Forest Use.

Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world's most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1-2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù.

Carbon in Amazon forests: unexpected seasonal fluxes and disturbance-induced losses.

The net ecosystem exchange of carbon dioxide was measured by eddy covariance methods for 3 years in two old-growth forest sites near Santarém, Brazil. Carbon was lost in the wet season and gained in the dry season, which was opposite to the seasonal cycles of both tree growth and model predictions. The 3-year average carbon loss was 1.3 (confidence interval: 0.0 to 2.0) megagrams of carbon per hectare per year. Biometric observations confirmed the net loss but imply that it is a transient effect of recent disturbance superimposed on long-term balance. Given that episodic disturbances are characteristic of old-growth forests, it is likely that carbon sequestration is lower than has been inferred from recent eddy covariance studies at undisturbed sites.