From Geodiversity to Geofunctionality: Quantifying Geodiversity-Based Ecosystem Services for Landscape Planning in French Guiana

Geodiversity assessment gained a prominent interest in the geoscientific community and beyond. However, it is not always sufficient for land planning or geoconservation. It is then pivotal to account for the contribution of functional geodiversity (i.e., geofunctionality), for instance declining the ecosystem services (ES) cascade model. However, by our knowledge, geodiversity-based ES (GES) have been rarely quantified. This paper aims to adapt existing ES-related approaches to quantify and map GES in French Guiana, a French Overseas territory located in the Amazon, where ongoing land use changes might affect ES supply. Seven GES were spatially assessed through an indicator-based approach accounting for both offered and used GES and merged into multiservice maps. Multiservice maps were then combined with a hemeroby index to highlight geofunctionality hotspots. Difference maps were finally used to compare geodiversity and geofunctionality patterns. The ES framework seems an effective way to quantitatively assess geofunctionality. Geodiversity and geofunctionality do not follow the same spatial patterns: very geodiverse areas can be poorly functional and vice-versa. Therefore, geodiversity and geofunctionality need to be both considered when it comes to landscape planning. This might be enhanced through hotspot mapping to highlight priority areas for planners. This study also focuses on the role of human inputs in GES supply and raises questions about the selection of proper indicators that should fit each step from the ES supply to management. High-quality datasets must be available and their occasional absence is a central matter of land planning that must be addressed before every decision-making process.