Evaluation of geodiversity in the Brazilian Amazon using different quantification methodologies

Abstract

When one considers geodiversity as the variability of abiotic elements distributed on the earth's surface in an unequal and complex manner, and that the configuration of these elements plays an important role in ecosystem dynamics, it becomes necessary and important to evaluate the different forms by which its spatial organization can be quantified and mapped. A recent academic effort in different countries, scales, and territories aims to evaluate and quantify geodiversity and its spatial variation. Thus, this work aims to apply and compare the spatial distribution of the geodiversity indices derived from four methodologies in the Brazilian Amazon. From this analysis, we seek to understand the distribution of the geodiversity indices in the Brazilian Amazon and organize a cartographic base for future correlations with spatial data representative of biodiversity and human appropriation of the territory. When one considers the tendencies of spatial similarity for each methodology, regardless of the size and shape of the quantification cells, the indices generated with the second methodology have a higher correlation with the basic index. In general, since they consider the same diversity measure (richness), the tendencies of direct spatial similarity are highlighted by the basic index and the products of the second methodology. The Shannon's index in the 250 × 250 km hexagonal grids, besides the high value of positive correlation, is also equivalent to the basic index, regaining the spatial proportion of each class, above all other indices. The indices generated from Shannon's and Simpson's indices tend to differ from the other indices because, besides class richness, they also measure evenness. The comparison between the quantitative indices shows some tendencies in the spatial patterns of geodiversity of the Brazilian Amazon but also presents indications of the limitations imposed by the different measurement criteria of the abiotic variables used.