What constitutes fine-scale geodiversity? Taxonomic geodiversity mapping across environmental gradients in a sub-Arctic mountain environment

Olli Karjalainen, Tuija Maliniemi, Anne-Mari Riikonen, Henriikka Salminen, Jan Hjort

The integration of geodiversity information, i.e., the diversity of abiotic features in the Earth surface and subsurface, into assessments of the sustainability and resilience of natural environments and ecosystems is increasingly considered important. However, geodiversity data is highly scale-dependent and there is an urgent need to find optimal ways on how geodiversity should be quantified and utilized. We use a recently proposed taxonomy of geodiversity framework to map geodiversity in a sub-Arctic environment in northern Finland characterized by a complex glacial footprint and diverse abiotic conditions. Field work was conducted at 193 study sites using 5- and 20-meter survey radii to map geofeatures, e.g., rock types, landforms, soils, hydrological, and topographical (geomorphons) elements at a very high thematic and spatial resolution. We additionally explored the spatial variability of geodiversity across cryogenic process activity, vegetation productivity, and climate gradients. Overall, 161 different geofeatures were recorded. Surveyed sites contained 15 geofeatures within 20 m radius, on average, while the most diverse sites hosted up to 28 different geofeatures. Individual components of geodiversity demonstrated distinct spatial patterns and relationship with environmental conditions underlining the multiple dimensions of geodiversity. Geofeature richness (georichness) increased most strongly along cryogenic activity gradient. Vegetation productivity had an overall negative association with georichness. Thematically detailed information on fine-scale geodiversity can improve our understanding of high-latitude geodiversity and further provide insights into the less studied aspects, such as functional geodiversity. The results also pave way for holistic geo- and biodiversity assessments, inform geoconservation efforts, and serve as a tool for identifying and monitoring environmental change and resilience.