Ecological function and diversity of scarabaeine dung beetles at degraded pastures in the Atlantic Forest biome

Abstract Pasture degradation is a global environmental problem, severely impacts soil quality, reducing efficiency of nutrient cycles, intensifying soil erosion and CO 2 emissions, and reducing overall soil biodiversity. Scarabaeinae dung beetles are particularly affected by the fact that they play a crucial role in ecosystem balance and nutrient cycling. This study evaluated the physical, chemical, and biological soil attributes, alongside the diversity and ecological functions of dung beetles, across pasture areas with two levels of degradation in the Atlantic Forest biome, Brazil. The work was carried out in 21 sample plots: 7 within native forest fragments (FF), 7 within low-degraded pastures (LDP), and 7 within high-degraded pastures (HDP). It was quantified carbon dioxide (CO 2 ) emissions, soil resistance to physical penetration, soil temperature, soil moisture, and carbon pools (total organic, labile, and recalcitrant C). Additionally, it was measured in dung beetle species richness, abundance, and their functional contributions to feces burial and soil excavation. Pasture degradation reduced environmental complexity, resulting in negative impacts on soil quality and beetle populations. Compared to FF areas, pastures exhibited reductions in total organic C (− 39%), labile C (− 36%), recalcitrant C (− 47%), and CO 2 emissions (− 38%), accompanied by increases in soil resistance to physical penetration (+ 34%) and soil temperature (+ 7%). Overall, pasture areas had a 55% reduction in beetle abundance and a 49% reduction in species richness compared to FF areas. Notably, LDP area maintained twice the abundance and diversity of dung beetles compared to HDP, where roller populations and feces burial activity were significantly reduced. Implications for insect conservation Land management strategies must be improved in agricultural landscapes of the Atlantic Forest to mitigate pasture degradation, increasing soil quality. Restoring and maintaining lower levels of pasture degradation is vital for preserving dung beetle diversity, which in turn safeguards critical ecosystem services such as organic C incorporation and soil nutrient cycling.