Plant diversity and generation of ecosystem services at the landscape scale: expert knowledge assessment.
In spite of the increasing amount of experimental evidence on the importance of plant species richness for ecosystem functioning at local scales, its role on the generation of ecosystem services at scales relevant for management is still largely unknown. To foster research on this topic, we assessed expert knowledge on the role of plant diversity in the generation of services at the landscape scale. We developed a survey that included three levels of organization and seven components of plant diversity; four provisioning, six regulating and four cultural services; as well as three resources and three conditions among key abiotic factors that are likely to provide a contribution to service generation equalling that of plant diversity. Eighty experts in areas of biodiversity, ecosystem functioning and services answered the survey. The experts identified species diversity within a community and diversity of communities within the landscape as the most important levels of organization for service generation, both with positive effects. Composition and number of species were considered to be the most relevant components of plant diversity, the latter with a positive effect on services. Water availability was identified as the most important abiotic resource. Our results suggest different approaches to management for sustaining the generation of services at the landscape scale. Provisioning services were perceived as largely influenced by abiotic resources and less so (although positively) by plant diversity. Regulating services were expected to strongly depend on both plant diversity and abiotic factors. A particularly strong positive effect of plant diversity was expected for the generation of cultural services. Some variation in answers could be attributed to expert background. Synthesis and applications. The expert survey generated detailed information and new hypotheses on the relationship between plant diversity and services at the landscape scale. Future research is needed to test these hypotheses, yet the areas of agreement identified in this study can be used immediately, with caution, as synthetic expert knowledge at spatial scales that are relevant for management, to guide technological and policy interventions ensuring the maintenance of biodiversity and ecosystem service delivery.