Background

Geodiversity refers to the variety of natural abiotic features, as the natural variety of geological (rocks, minerals), geomorphological (landforms, physical processes), hydrological and soil properties. The parameter “geomorphodiversity” is a measure of the dynamics of the Earth’s surface and it has a key role in conservation of biodiversity and sustainability of ecosystems. Thus, it affects evolution of the biotic world and of human life. A measure of geomorphodiversity in time relates to the evolutionary stage of the physical processes shaping the landscape. This is particularly relevant in an era of pervasive anthropic actions and even more so with the onset of climate change.

Purpose

Our goal is studying in a quantitative, objective and reproducible way the geodiversity of Italy, its peculiarities in urban areas, and its relationship with geo-hydrological hazards. The research defines a synthetic index to summarize the degree of diversity of abiotic parameters at national level, first; then, it analyzes selected locations at local/urban level, within the same index and with the higher resolution data.

Methods

We single out urban areas with a novel technique, and aggregate probabilities for geohazards at slope unit level. Thus, we can describe geodiversity, the degree of urbanization, and hazards, at comparable resolution at the national level. At regional and local scales, we rely on data from LiDAR measurements with drones and photogrammetry applied to historical photographs, to reveal links between local geodiversity and hazards in urban and suburban areas.

Results

We propose a quantitative geodiversity index, GmI, calculated at national scale combining high-resolution elevation data, for they are the basis for geomorphometric analysis and automated classification of landforms, and thematic data. Interpretation of the index is straightforward, allowing a many applications. Implications of different values of the index, in combination with geo-hydrological hazard, are prominent within urban areas.