Biodiversity and carbon conservation under the ecosystem stability of tropical forests.

Although efforts to protect high levels of biodiversity and carbon storage can greatly increase the effectiveness of species loss and climate change mitigation, there is evidence indicating a trade-off scenario for their conservation at regional scale. Decisions making in trade-off scenarios can be supported by including information on the ecosystem stability of tropical forests (i.e., the ability of the ecosystem to maintain its function over time). Forest stability may affect biodiversity integrity and the residence time of carbon stored in tree biomass. Here, we assess the stability of old-growth forests' productivity by analyzing a 19-year time series of the Normalized Difference Vegetation Index (NDVI). We also used geoprocessing tools to analyze the overlap among forest-specialist vertebrate species richness, carbon density, and stability of old-growth forest throughout the Brazilian Atlantic Forest. We used model selection to find environmental predictors of the stability of primary productivity and build a predictive map of potential stability. Then, we overlapped maps of potential stability, species richness of forest-specialist vertebrates, and carbon density to identify hotspot areas of biodiversity and carbon density occurring at highest and lowest potential stability. We found that forest stability increases from north to south along the Atlantic Forest. High biodiversity occurs mainly at low stability while high carbon stock at high stability. Spatial overlap of the hotspots, where conservation co-benefits high biodiversity and carbon stock, occurs mostly at high stability in a large area along part of the coast and in smaller inland areas of the southern region. Most of the hotspots with low stability for biodiversity, carbon stock and combination of both are found in unprotected areas. Hence, the strategic mitigation of species loss and carbon emissions lies in three approaches: prioritizing forest protection in unprotected hotspots; implementing forest management practices in protected hotspots with low stability; and enforcing a comprehensive regime of protection and management in hotspots that exhibit low stability. Focused on forest stability, these approaches involve ecosystem-based planning offering Brazil's government effective strategies to fulfill its commitments in biodiversity conservation and carbon emission reduction.

Drivers of geographical patterns of North American language diversity.

Although many hypotheses have been proposed to explain why humans speak so many languages and why languages are unevenly distributed across the globe, the factors that shape geographical patterns of cultural and linguistic diversity remain poorly understood. Prior research has tended to focus on identifying universal predictors of language diversity, without accounting for how local factors and multiple predictors interact. Here, we use a unique combination of path analysis, mechanistic simulation modelling, and geographically weighted regression to investigate the broadly described, but poorly understood, spatial pattern of language diversity in North America. We show that the ecological drivers of language diversity are not universal or entirely direct. The strongest associations imply a role for previously developed hypothesized drivers such as population density, resource diversity, and carrying capacity with group size limits. The predictive power of this web of factors varies over space from regions where our model predicts approximately 86% of the variation in diversity, to areas where less than 40% is explained.