Geodiversity Index Map as a Tool for Spatial Analysis: Methodological Approaches and Applications in the Western Amazon

Recent advances in geodiversity studies have underscored the necessity for methodologies that can assess its spatial distribution and correlation with biodiversity and cultural heritage. Existing approaches, such as Geodiversity Index Maps (GIMs), provide a robust framework for comprehensive and objective evaluations, particularly in vast and logistically remote regions like the Amazon. This study applies an adapted GIM methodology to the municipality of Presidente Figueiredo, northern Amazonas, Brazil, integrating four sub-indices (geological, pedological, geomorphological, and hydrographic) using open-access data. Our results identify two key areas of high geodiversity: the southern basin-craton transition zone and northern regions featuring linear geological structures and alluvial deposits. Conversely, the lowest values are concentrated in the inundated area of the Balbina reservoir, where water submerges the terrestrial landscape, homogenizing its surface and coinciding with the documented biodiversity loss following the damming of the Uatumã River. This study demonstrates the efficacy of GIMs in displaying priority areas for territorial management and its value as a tool for visualising complex geospatial data in diverse environments. The observed spatial correlation between high/low geodiversity zones and the environmental context in this area raises a key question: to what extent does geodiversity sustain Amazonian biodiversity? The findings of this study contribute to geoheritage assessments and support sustainable land-use planning in ecologically sensitive regions.