“Biodiversity has a major role in sustaining the productivity of Earth’s ecosystems” [Duffy 2017: 263]. This is the conclusion drawn from an analysis of 133 estimates reported in 67 field studies on the effects of species richness (number of species) on biomass production, isolating biodiversity as a variable from other factors that affect productivity (nutrient availability and climate). The results validate theoretical predictions and corroborate lab experiments showing that greater biodiversity leads to greater ecosystem production, while also refuting prevailing doubts about the significance, after accounting for other factors, of biodiversity’s effect on productivity.
Because of the long history of skepticism that species diversity affects productivity of natural ecosystems, the strength and consistency of results presented here were unanticipated. In every case we found the opposite of long-standing views expressed in the ecological literature. Ecosystems with high species richness commonly had higher biomass and productivity in observational field data from a wide range of taxa and ecosystems, including grassland plants, trees, lake phytoplankton and zooplankton, and marine fishes. Observed positive associations of biodiversity with production in nature were stronger when covariates were accounted for, stronger than biodiversity effects documented in controlled experiments, and comparable to or stronger than associations with climate and nutrient availability, which are arguably two of the strongest abiotic drivers of ecosystem structure and functioning, as well as major global change drivers. Our results also corroborate findings of a recent synthesis of experimental data reporting that biodiversity effects are comparable in magnitude to major drivers of global change, and extend related conclusions based on observational data from forests and dryland plants to a broad range of ecosystems [Duffy 2017: 263].
Integration of this perspective [on the vital role of biodiversity] into global change policy is increasingly urgent as Earth faces widespread and potentially irreversible losses and invasions of species, which are already changing ecosystems [Duffy 2017: 263].
Observed positive associations of biodiversity with production in nature were … comparable to or stronger than associations with climate and nutrient availability, which are arguably two of the strongest abiotic drivers of ecosystem structure and functioning, as well as major global change drivers [Duffy 2017: 263].
Duffy, J. Emmett, et al, 2017, Biodiversity effects in the wild are common and as strong as key drivers of productivity, Nature 549, http://www.nature.com/nature/journal/v549/n7671/full/nature23886.html