Land surface diversity: A geomorphodiversity index of Italy

Geomorphodiversity refers to the variety of landforms and morphological processescharacterizing the landscape. The definition of an index to quantifygeomorphodiversity is a relevant step for multiple fields of Earth sciences, since it iswidely accepted that the variability of the geosphere deeply influences the diversityof the biosphere. Such an index should describe the number and type of landformsand geomorphological processes. We propose a quantitative land surface diversityindex valid for Italy, considering multiple input quantities to describe geological con-straints and geomorphological processes. Critical issues were the selection of movingwindow size for focal statistics operations, to calculate local diversity of slope, lithol-ogy, drainage density and terrain forms in individual raster maps. We compared theindex with traditional geomorphological maps, in selected locations, in which infor-mation was available. Results show that a minimal set of heterogeneous data is a sat-isfactory approach to investigate the landscape diversity. Relating processingparameters and terrain spatial characteristics to the dataset resolution is a goodchoice to assess a reproducible land surface diversity index. Inclusion of drainagedensity allows the improvement of results in flat areas, in which other factors showtrivial results. We argue that the index is relevant for land use management, assess-ment of ecodiversity, and it may help describing the interaction between abiotic andbiotic compartments.