CLIMIFUN have led to the first global atlas of dominant bacterial taxa. Here, we showed that only 2% of bacterial phylotypes (~500 phylotypes) consistently accounted for almost half of the soil bacterial communities worldwide. Despite the overwhelming diversity of bacterial communities, relatively few bacterial taxa are abundant in soils globally. We clustered these dominant taxa into ecological groups to build the first global atlas of soil bacterial taxa, published in Science in January (Delgado-Baquerizo et al. 2018. Science 359: 320–325). A major breakthrough of this study is that habitat preferences are not predictable from phylum-level identity alone, given that all of the ecological clusters included phylotypes from multiple phyla. By narrowing down the number of phylotypes to be targeted in future studies from tens of thousands to a few hundred, our study paves the way for a more predictive understanding of soil bacterial communities, which is critical for accurately forecasting the ecological consequences of ongoing global environmental change.
CLIMIFUN has investigated the changes in soil biodiversity during ecosystem development (PNAS, 2019). Changes in belowground biodiversity during pedogenesis followed two main patterns. In lower productivity ecosystems (drier and colder), increases in belowground biodiversity tracked increases in plant cover. In more productive ecosystems (wetter and warmer), increased acidification during pedogenesis was associated with declines in belowground biodiversity. Changes in the diversity of bacteria, fungi, protists, and invertebrates with pedogenesis were strongly and positively correlated worldwide, highlighting that belowground biodiversity share similar ecological drivers as soils and ecosystems develop. Together, our findings provide evidence that ecological patterns in belowground biodiversity are predictable across major globally-distributed ecosystem types, and suggest that shifts in plant cover and soil acidification during ecosystem development are associated with changes in belowground biodiversity over centuries to millennia.
CLIMIFUN has also provided the first global assessment of the environmental factors controlling the priming effect (Nature Communications, 2019). Our work showed that the magnitude of the positive apparent priming effect (increase in CO2 release through accelerated microbial biomass turnover) was negatively associated with SOC content and microbial respiration rates. Our statistical modeling suggests that apparent priming effects tend to be negative in more mesic sites associated with higher SOC contents. In contrast, a single-input of labile C causes positive apparent priming effects in more arid locations with low SOC contents. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios.
CLIMIFUN also investigated the importance of microbial communities as predictor of multifunctionality resistance (C, N and P cycling) to climate change and nitrogen fertilization. This work was published in Ecology Letters in September 2017 (Delgado-Baquerizo et al. 2017. Ecology Letters 20: 1295–1305).
