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Increasing soil carbon and nitrogen storage can help mitigate climate change and sustain soil fertility1,2. A large number of biodiversity-manipulation experiments collectively suggest that high plant diversity increases soil carbon and nitrogen stocks3,4. It remains debated, however, whether such conclusions hold in natural ecosystems5–12. Here we analyse Canada’s National Forest Inventory (NFI) database with the help of structural equation modelling (SEM) to explore the relationship between tree diversity and soil carbon and nitrogen accumulation in natural forests. We find that greater tree diversity is associated with higher soil carbon and nitrogen accumulation, validating inferences from biodiversity-manipulation experiments. Specifically, on a decadal scale, increasing species evenness from its minimum to maximum value increases soil carbon and nitrogen in the organic horizon by 30% and 42%, whereas increasing functional diversity enhances soil carbon and nitrogen in the mineral horizon by 32% and 50%, respectively. Our results highlight that conserving and promoting functionally diverse forests could promote soil carbon and nitrogen storage, enhancing both carbon sink capacity and soil nitrogen fertility.Analysis of data from the Canadian National Forest Inventory database suggests that greater tree diversity in natural forests is associated with increases in soil carbon and nitrogen stocks. [ABSTRACT FROM AUTHOR]

Examining biogeographical variations in species' diet is important for linking key ecological traits between consumers and their environment. While the trophic ecology of the Holarctic martens has been globally synthesised, systematic information on the feeding ecology of martens (Martes spp.) in Asia is still deficient compared to species in Europe and North America. Here we conduct a meta-analysis based on literature describing regional and seasonal variation in diet composition of the Japanese marten (Martes melampus). Across nine study areas in the Japanese archipelago, annual marten diet mainly comprised fruits, invertebrates, and mammals. Cluster analysis divided these into three groups according to the similarity in composition. Dietary niche breadth and the relative frequency of occurrence of the mammalian prey was significantly higher in sub-alpine/cool-temperate than warm-temperate thermal forest zones, whereas the occurrence of fruits was significantly higher in warm-temperate than sub-alpine/cool-temperate zones. Seasonal analysis showed significant effects across all four seasons on the frequency of occurrence of mammals, invertebrates, and fruits. The Japanese marten is a flexible and opportunistic feeder with the potential to maintain its key macronutrient requirements by adapting its feeding strategy to changes in resource variability and environmental conditions. This trophic plasticity may advantage the Japanese marten in coping with human-induced rapid environmental change, as global analysis has projected for martens across other regions. [ABSTRACT FROM AUTHOR]