Biodiversity is declining world-wide with detrimental effects on ecosystems. However, we lack a quantitative understanding of the shape of the relationship between microbial biodiversity and ecosystem function (BEF). This limits our understanding of how microbial diversity depletion can impact key functions for human well-being, including pollutant detoxification. Three independent microcosm experiments were conducted to evaluate the direction (i.e. positive, negative or null) and the shape of the relationships between bacterial diversity and both broad (i.e. microbial respiration) and specialized (i.e. toxin degradation) functions in five Australian and two UK freshwater ecosystems using next-generation sequencing platforms. Reduced bacterial diversity, even after accounting for biomass, caused a decrease in broad (i.e. cumulative microbial respiration) and specialized (biodegradation of two important toxins) functions in all cases. Unlike the positive but decelerating BEF relationship observed most frequently in plants and animals, most evaluated functional measurements were related to bacterial diversity in a non-redundant fashion (e.g. exponentially and/or linearly). Synthesis. Our results suggest that there is a lack of functional redundancy in the relationship between bacterial diversity and ecosystem functioning; thus, the consequences of declining microbial diversity on ecosystem functioning and human welfare have likely been considerably underestimated.
Bibliographical noteFunding Information:
We thank Fernando T. Maestre (Universidad Rey Juan Carlos, Spain) and Nico Eisenhauer (University of Leipzig, Germany) for helpful comments on previous versions of the manuscript, and all the technicians and colleagues that helped with the field surveys and laboratory analyses. In addition, we thank Jasmine Grinyer for revising the English of this manuscript. This research is supported by the ARC project (DP13010484). The authors declare no competing financial interests.
© 2016 The Authors. Journal of Ecology © 2016 British Ecological Society
- broad functions
- ecosystem services
- freshwater ecosystems
- microbial richness
- specialized functions
- toxin degradation