Shedding light on relationships between plant diversity and tropical forest ecosystem services across spatial scales and plot sizes

This paper sheds light on the state of our knowledge of relationships between plant diversity and tropical forests ecosystem services. We systematically reviewed the empirical evidence of relationships between three ecosystem services: carbon stock and sequestration, timber provisioning and non-timber forest product (NTFP) provisioning, and three dimensions of plant diversity: taxonomic, functional and structural. We carried out meta-analyses to assess their validity across spatial scales and plot sizes. We found that indicators of all three dimensions of plant diversity have reported relationships with at least two of the studied ecosystem services, but there has been limited and inconsistent use of plant diversity indicators and little attention for relationships with timber and NTFP services. Nevertheless, we found that tree species richness showed robust significant positive correlations with carbon stock across the tropics, and that the geographical extent of the study area had a significant negative effect on the strength of this relationship, where the strength of the relationship decreased with increasing geographical extent. This paper reveals a knowledge gap for services other than carbon stock and shows that at local to regional spatial scales, synergies can be achieved between policies focused on biodiversity conservation and maintenance of carbon stocks