Concepts of geodiversity and biodiversity interactions across different scales

<p>It has been proposed that geodiversity (the diversity of geological, geomorphological and pedological features) is positively correlated with biodiversity. This suggests that by preserving geodiversity, we can also preserve biodiversity and the associated ecosystem functions. However, a significant correlation between geodiversity and biodiversity measures does not mean causation and does not distinguish spatial and temporal scale dependencies of the processes involved. In fact, such a correlation could also imply that biodiversity estimates can predict geodiversity. These aspects have, nonetheless, rarely been considered in geo- and biodiversity studies, which constrains the applicability of these analyses in, for example, models of geo- and biodiversity distribution that rely on explicit processes. We aim to explore the interactions between geo- and biodiversity across different scales, identifying the key mechanisms that link them.</p> <p>The feedbacks between geodiversity and biodiversity start at the microscale during the process of soil aggregation and formation, driven by microbial diversity such as fungi and biological soil crusts, as well as by plant roots. On the other hand, soil texture defines microsites for microbial life, and surface types and quality shape their colonization process. At intermediate landform or catchment scales, the spatial variability of topographical, lithological and soil features benefits the formation of diverse habitats and resources for biota (e.g. plants, vertebrates and invertebrates), which, at the same time, will affect radiation distribution, erosion and nutrient availability. At even larger scales, processes like mantle dynamics and the number of plate boundaries can determine regional-scale shifts in ecosystems, isolation processes and the evolution of biota. Similarly, temporal variability determined by, e.g. microclimate, catchment scale meteorology or orographic effects, induces niche variability within a spatial scale. Finally, based on these process-related relationships at variable scales, we suggest a list of geodiversity parameters to be used when assessing geo- and biodiversity interactions.</p>