Can habitat disturbance promote biodiversity?
“Disturbance events such as volcanic eruptions modify ecosystems by changing the physical environment and resource availability. However, there is a notable lack of paleontological research addressing disturbance ecology in volcanic habitats. This study addresses the under-researched field of disturbance palaeoecology in volcanic regions by examining ecosystem dynamics within the Bolzano Supervolcano, the largest and best-exposed Permian supervolcano in Europe. Here, we introduce the Gocciadoro ichnosite, representing a Cisuralian alluvial fan shaped by discrete disturbance events, specifically hyperconcentrated debris flows within the caldera. Each disturbance event is recorded as a depositional couplet consisting of a bioturbated siltstone interval overlying a sandstone unit with no discernible trace fossils. Bioturbation is represented by unlined, unbranched burrows (Planolites) occurring at high densities (bioturbation intensity>90 %). We propose a three-stage model to describe the ecological succession: 1) Pre-disturbance stage corresponding to an unvegetated alluvial fan; 2) Disturbance stage where the deposition provided a new nutrient-rich surface; 3) Post-disturbance stage where an opportunistic community of r-selected deposit-feeding organisms colonized the newly deposited substrate. The absence of K-selected taxa suggests that disturbances were exceptionally frequent, with common sediment-gravity flows and stressful background conditions preventing the development of a climax community. In this harsh ecologic scenario, the disturbance events did not have just destructive effects but promoted higher levels of biodiversity by increasing nutrient availability and forming new habitats.” in Paleo3