Plant diversity enhances provision of ecosystem services: A new synthesis

Biodiversity is known to play a fundamental role in ecosystem functioning and thus may positively influence the provision of ecosystem services with benefits to society. There is a need for further understanding of how specific components of biodiversity are affecting service provision. In this context, terrestrial plants are a particularly important component of biodiversity and one for which a wealth of information on biodiversity-ecosystem functioning relationships is available. In this paper, we consider terrestrial plants as providers of ecosystem services and analyze whether manipulating plant diversity has an effect on the magnitude of ecosystem service provision using a meta-analysis of 197 effect sizes and a vote-counting analysis of 361 significance tests. The results of these analyses are compared with those of a previous meta-analysis that included a wide diversity of service providers. We produce a synthesis table to explicitly link plants as service providers to indicators of ecosystem properties and these to ecosystem services. By focusing on only plants, we found a clear positive effect of biodiversity on six out of eight services analyzed (provisioning of plant products, erosion control, invasion resistance, pest regulation, pathogen regulation and soil fertility regulation). When controlling for pseudoreplication (repeated records from single studies), we found that four of the six positive effects remained significant; only pest regulation and soil fertility showed non-significant effects. Further expanding our basis for inference with the vote-counting analysis corroborated these results, demonstrating that quantitative meta-analysis and vote-counting methods are both useful methods to synthesize biodiversity ecosystem service studies. Notwithstanding the restricted number of identified services, our results point to the importance of maintaining plant diversity to ensure and increased provision of ecosystem services which benefit human well-being.