Metrics for assessing ecosystem service tradeoffs and bundles

Background/Question/Methods

Assessments of changes in ecosystems need to account for the ability of ecosystems to supply and deliver services to societies but also on tradeoffs and synergies among services. Yet, little is known about how services are related to each other and which services can be delivered in the same spatial areas. Metrics that can convey different aspects of such relationships are urgently needed to identify the consequences of management decisions at local to global scales. In this paper we use three very different metrics to assess tradeoffs or synergies among services: i- the nature, shape and position of individual data points of pair-wise correlations among services, ii- evenness among services, iii- bundles of services emerging from multivariate classification algorithms. We use data for 9 cases studies across the globe differing in: i- the size of the study area (from a single small watershed to a whole country), and ii- the methods used to estimate service magnitudes (statistics, process-based models, and data driven models). We have data for 17 services; we distinguish potential supply of services from actual delivery to society; we distinguish flows from stocks. We explore how these metrics can elucidate the role of biophysical and societal drivers on the analyzed tradeoffs by dissecting the study case areas into polygons corresponding to different land-use/land-cover (LULC), eco-regions and states or municipalities.

Results/Conclusions

We found that the shape, the dispersion of data points and the direction of pair-wise correlations of specific services changed across study cases. LULC, eco-regions and states/municipalities explained differences among these correlations across most study cases. A large proportion of the analyzed polygons showed high levels of service evenness across study cases; yet large differences across study cases, types of LULC, eco-regions and states/municipalities were found for those polygons with low levels of evenness among services. The nature of bundles of ecosystem services varied widely across study cases, LULC, eco-regions and states/municipalities. We discuss what kind of information can be derived from these indicators on the differences among and within study cases. We suggest the best ways to report on tradeoffs and bundles of services in the context of multi-scale global initiatives for monitoring ecosystem services such as those by GEOBON-ES (Group on Earth Observations- Biodiversity Observation Network- Ecosystem Services) and discuss how these indicators can be linked to global targets (e.g. Aichi targets).