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1. Although plantation forests are being established at an increasing rate, their effects on biodiversity are still debated.2. Native candeias [Eremanthus erythropappus (DC.) Mac Leish] and exotic eucalyptus (Eucalyptus spp.) have recently been planted on Cerrado grasslands. The Cerrado is the second largest biome of Brazil and one of the most threatened savanna ecosystems.3. Here, we use dung beetles (Scarabaeinae) to investigate the effects of the landuse changes associated to afforestation on Cerrado insect biodiversity. We sampled dung beetles in candeia (4-and 6-year-old) and eucalyptus plantations (1-and 4-year-old), natural candeia formations (candeiais), native grasslands and natural forests.4. Dung beetle diversity in plantations was lower than in grasslands and forests, but was not different from diversity in natural candeiais. Candeia and 1-year-old eucalyptus plantations, grasslands and natural candeiais all had similar community composition, distinct from natural forests. Four-year-old eucalyptus plantations were intermediate between those two groups. Overall, afforestation was detrimental for dung beetles. 5. Differences between exotic and native plantations were only apparent in older plantations, and seemed to be due to differences associated to canopy openness rather than to the origin of the planted species. Candeia plantations were of better conservation value for open-area species (62% species shared between grasslands and candeia plantation) whereas eucalyptus plantations were so for forest species (26% species shared between forests and eucalyptus plantations). We recommend considering this result before deciding where to plant which species.

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Root rots are a constraint for staple food crops and a long-lasting food security problem worldwide. In common beans, yield losses originating from root damage are frequently attributed to dry root rot, a disease caused by the Fusarium solani species complex. The aim of this study was to model the current potential distribution of common bean dry root rot on a global scale and to project changes based on future expectations of climate change. Our approach used a spatial proxy of the field disease occurrence, instead of solely the pathogen distribution. We modeled the pathogen environmental requirements in locations where in-situ inoculum density seems ideal for disease manifestation. A dataset of 2,311 soil samples from commercial farms assessed from 2002 to 2015 allowed us to evaluate the environmental conditions associated with the pathogen’s optimum inoculum density for disease occurrence, using a lower threshold as a spatial proxy. We encompassed not only the optimal conditions for disease occurrence but also the optimal pathogen’s density required for host infection. An intermediate inoculum density of the pathogen was the best disease proxy, suggesting density-dependent mechanisms on host infection. We found a strong convergence on the environmental requirements of both the host and the disease development in tropical areas, mostly in Brazil, Central America, and African countries. Precipitation and temperature variables were important for explaining the disease occurrence (from 17.63% to 43.84%). Climate change will probably move the disease toward cooler regions, which in Brazil are more representative of small-scale farming, although an overall shrink in total area (from 48% to 49% in 2050 and 26% to 41% in 2070) was also predicted. Understanding pathogen distribution and disease risks in an evolutionary context will therefore support breeding for resistance programs and strategies for dry root rot management in common beans.

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