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 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

How pervasive is biotic homogenization in human-modified tropical forest landscapes?

Abstract Land-cover change and ecosystem degradation may lead to biotic homogenization, yet our understanding of this phenomenon over large spatial scales and different biotic groups remains weak. We used a multi-taxa dataset from 335 sites and 36 heterogeneous landscapes in the Brazilian Amazon to examine the potential for landscape-scale processes to modulate the cumulative effects of local disturbances. Biotic homogenization was high in production areas but much less in disturbed and regenerating forests, where high levels of among-site and among-landscape b-diversity appeared to attenuate species loss at larger scales. We found consistently high levels of b-diversity among landscapes for all land cover classes, providing support for landscape-scale divergence in species composition. Our findings support concerns that b-diversity has been underestimated as a driver of biodiversity change and underscore the importance of maintaining a distributed network of reserves, including remaining areas of undisturbed primary forest, but also disturbed and regenerating forests, to conserve regional biota

A quantitative baseline of ants and orchid bees in human-modified Amazonian landscapes in Paragominas, Pará, Brazil.

The lack of effective biodiversity baselines is a major impairment to implement conservation plans. Hence, constructing and updating species lists provides vital information about species distribution records. The Sustainable Amazon Network (in Portuguese Rede Amazônia Sustentável; RAS) is an interdisciplinary research initiative that aims to evaluate land-cover changes effects in eastern Brazilian Amazonia. Within the scope of this project, we sampled ants and orchid bees and herein present a list of species collected in Paragominas, PA, Brazil; the most complete lists of species published to date of these groups for the eastern Amazon. We sampled these insects across several land-cover types, from undisturbed primary forest, through varyingly disturbed primary and secondary forests to production areas (silviculture, pastures and arable fields). In total we recorded 285 species of ants and 36 species of orchid bees. Species richness was higher in primary forests for both groups, followed by production areas. Orchid bees reached their highest richness in secondary forests. For orchid bees, production areas were dominated by a few hyper-dominant species, such as Eulaema nigrita. We acknowledge that the use of different sampling methods would collect additional species, and we recommend this for future assessments if the aim is to make a complete inventory. We expect this study can be used as a baseline for understanding the effectiveness of ongoing changes in forest conservation and land management practices. Finally, this list is of suitable importance in determining conservation status for several taxa described here

The spatial distribution of canopy- resident and ground-resident cereal aphids (Sitobion avenae and Metopolophium dirhodum) in winter wheat

We investigated, within two cereal fields in Southern England, the within-canopy spatial distribution of the aphids Sitobion avenae and Metopolophium dirhodum in relation to crop yield and plant nitrogen. We extended the study to investigate the spatial distribution of aphids that fell to, or returned from, the ground in order to estimate availability of the within-canopy aphid population to ground-active predators. We revealed that crop canopy aphid spatial pattern was associated with nitrogen or yield. Differences were evident between species: S. avenae was generally negatively associated with yield or plant nitrogen, whilst M. dirhodum exhibited positive association. For both aphid species, we observed strong spatial pattern for aphids falling to the ground and conclude that this could, in part, mediate the effectiveness of ground-active predators as pest control agents