Season, not long-term warming, affects the relationship between ecosystem function and microbial diversity

Abstract

1AbstractAcross biomes, soil biodiversity promotes ecosystem functions. However, whether this relationship will be maintained under climate change is uncertain. Here, using two long-term warming experiments, we investigated how warming affects the relationship between ecosystem functions and microbial diversity across seasons, soil horizons, and warming duration. The soils in these warming experiments were heated +5 °C above ambient for 13 or 28 years. We measured seven different ecosystem functions representative of soil carbon cycling, soil nitrogen cycling, or nutrient pools. We also surveyed bacterial and fungal community diversity. We found that the relationship between ecosystem function and bacterial diversity and the relationship between ecosystem function and fungal diversity was unaffected by warming or warming duration. Ecosystem function, however, was significantly affected by season, with autumn samples having higher function than summer samples. Our findings further emphasize that season is a consistent driver of ecosystem function and that this is maintained even under simulated climate change.ImportanceSoils perform a variety of ecosystem functions, and soil microbial communities with higher diversity tend to promote the performance of these functions. Yet, biodiversity loss due to climate change threatens this relationship. Long-term global change studies provide the opportunity to examine the trajectory of the effects of climate change. Here, we utilized two long-term warming experiments, where soils have been heated +5 °C above ambient temperature for 13-28 years, to understand how increased temperatures affect the relationship between ecosystem function and soil microbial diversity. We observed that the effects of increased temperature on the relationship between bacterial diversity and ecosystem function were season-specific. This work emphasizes the role that environmental conditions, such as season, have on modulating effects of climate change. Additionally, these findings demonstrate the value of long-term ecological research in furthering our understanding of climate change.