Geodiversity Assessment of French Guiana: Challenges and Implications for Sustainable Land Planning

Abstract

As operational concept, geodiversity implies a measurement and its application narrowed to a given spatial area, allowing the identification of clusters for prioritization and planning purposes. This study proposes a first geodiversity index assessment for French Guiana, a French Oversea territory located within the Guiana Shield (South America). Almost entirely covered by the Amazon rainforest associated with an exceptional biodiversity, French Guiana appears as an international conservation and land-planning challenge facing multiple issues (e.g. urban, agricultural and industrial growth, forest management, mining planning).Geodiversity assessment is performed through a grid-based approach. A geodiversity index is calculated as the sum of four sub-indices (lithodiversity and unlithified diversity, mineral diversity, hydrodiversity, geomorphodiversity). The index calculation is based on the number of entities within each grid-cell. Spatial correlation is used to identify geodiversity clusters and finally the index is aggregated at different spatial units relevant for land-planning (e.g. municipalities, hydrographic sectors, areas of ecological interest, the Guiana Amazonian Park and the Departmental Mining Plan).The results show that the geodiversity index is mainly controlled by lithodiversity and that high geodiversity clusters are located along the gold-bearing greenstone belts crossing the territory. However, spatialized data concerning geodiversity are still inadequate or unavailable to perform proper operational assessments in French Guiana. Furthermore, based on qualitative examples, we discuss that the assessment of diversity alone might not be always enough for geoconservation nor land-planning perspectives. It is pivotal to account for the geonfunctionalityi.e. the contribution of geodiversity to the functioning of socio-ecological systemsand its interaction with anthropic activities.

Effect of spatial scale of soil data on estimates of soil ecosystem services: Case study in 100 km2 area in France

“…To characterise this relationship, absolute changes from the ES1000 to the ES50 maps in the ESs levels aggregated according to landforms, land uses or municipalities are plotted against similar absolute changes in pedodiversity (Figure 6a–d). As suggested in other studies (Scammacca et al, 2022), Figure 6 clearly shows quantitatively that changes in pedodiversity do not induce direct, simple or systematic changes in ESs levels. Several interesting behaviours may however be recognised.…”

“…As suggested in other studies (Scammacca et al, 2022), Figure 6 clearly shows quantitatively that changes in pedodiversity do not induce direct, simple or systematic changes in ESs levels. Several interesting behaviours may however be recognised.…”

Geoeducational assessments in Khon Kaen National Geopark, Thailand: implication for geoconservation and geotourism development

“…As per the geodiversity theory of Gray (2013) , the inventories and characterisation of the KKGp can be classified through fossils, landforms, landscapes, rocks, and minerals. The classification methods ( Ruban, 2010 ; Neches, 2016 ; Ponjiger et al., 2021 ; Pal and Albert, 2021 ; Ferrando et al., 2021 ; Dias et al., 2021 ; de Paula Silva et al., 2021 ; Chrobak et al., 2021 ; Scammacca et al., 2022 ; Carrion-Mero et al., 2022 ) suggest that these geosites have potential as paleontological, geomorphological, stratigraphical, petrological, and mineralogical sites.…”

Geodiversity in the Amazon drainage basin

“…Based on the geodiversity index map, it is most likely that suitable geosites can be found in the AOB, the cratons, and along the areas with high hydrological diversity in the sub-Andean foreland basins, the Solimões and Amazonas sedimentary basins. However, it is important to note that a previous study noticed that areas that ranked low in geodiversity were still of high ecological interest due to important lithological and geomorphological features found there [35]. Thus, simply using a grid-based approach is insufficient, and it is advised to combine a grid-based method using the approach as suggested by Brilha [19], which can be regarded as a qualitative-quantitative method as proposed by Zwolinski et al [175].…”

“…Only few papers have described the geodiversity in the ADB until now, including four papers that discuss geodiversity in the Amazon, namely on the 'Amazônia legal' in Brazil [37] (the northern states of Brazil, including Mato Grosso and the west of Maranhão), the Xingu river basin [38], French Guiana [35] and the NAPO Sumaco (aspiring UNESCO) Geopark [53] (figure 1). De Andrade et al [37] conducted an extensive literature study of geodiversity in the 'Amazônia legal' and concluded that there is still little known about geodiversity in this region, neither is there information on a detailed scale.…”