Alike other animals, cows generate excrement due to the digestive process. An average bovine produces approximately 30 kilograms of excrement daily, adding up to more than 10 tons per year per individual. In Spain, with more than 6.5 million head of livestock, excrement production is significant, playing a crucial role in nutrient cycles. An important fraction of this excrement is processed by decomposer organisms, among them dung beetles. Through their activity, these insects eliminate and bury the feces of herbivores. In this way, they not only facilitate nutrient cycling but also contribute to soil aeration, reduction of greenhouse gas emissions, seed dispersal and parasite control.
This group is inextricably related with livestock farming, an agricultural practice of vital economic and social importance that is divided into extensive and intensive systems. Extensive livestock farming, considered more sustainable, produces high-quality meat and dairy products, while intensive livestock farming is based in higher cow densities, and the frequent use of food supplements, antibiotics, antiparasitics, exotic plant species and fertilizers, so it has important negative impacts on soils and biodiversity.
We gathered an international team, co-lead by the National Museum of Natural Sciences (MNCN-CSIC), and the Autonomous University of Madrid (UAM) to evaluate how the diversity of dung beetles affects the decomposition of excrement in grasslands of different livestock regimes using field experiments. The results of this work have just been published in in Nature Communications, and provide crucial information for the sustainable management of biodiversity and ecosystem services in the agricultural sector. In general, the number of dung beetle species is higher in extensive grasslands, and the number of species is one of the main determinants of the amount of decomposed excrement. But in addition, using meta-analysis techniques we established that greater functional diversity in these insects translates into greater efficiency in excrement removal, regardless of the livestock regime. This suggests that promoting functional diversity in agrosilvopastoral landscapes can balance food production with biodiversity conservation, reinforcing the importance of agricultural and livestock management strategies that promote this diversity.
You can read the full press releases of MNCN-CSIC and UAM (both in Spanish), or get acces to the full paper at: https://jhortal.com/project/noriega-et-al-nat-comm-2023-dung-removal-increases-under-higher-dung-beetle-functional-diversity-regardless-of-grazing-intensification/