Dung beetles in south american pasturelands : geographical distribution and effects of climate change

Abstract

Pasturelands are grasslands used for raising cattle that are formed by natural or exotic vegetations, especially grasses. Insect biodiversity in grazing environments is highly valuable, especially when sustainable production is considered. Dung beetles are essential to sustainability in pasturelands because the burial of feces promote ecological services that are essential to maintain a healthy environment. Different species relate to environmental benefits in different scales, thus it is important to know which species are present in pasturelands, where they originally come from and what ecological services they can provide. Here I gather all information about dung beetle species native to South America that are well defined taxonomically and known to feed on cattle dung. Also, I investigate what consequences climate change may cause on the geographical distribution of the four dung beetle species considered as most important for Brazilian pasturelands. In South America 57 dung beetle species are known to occur in grazing areas and feed on cattle manure, comprehending the following biomes with native and/or introduced grasslands (including deforested areas within forest biomes): Chaco, Pantanal, Cerrado, Caatinga, Pampa, Atlantic Forest, Amazon Forest, Paramo, Puna, Llanos, and Patagonia. The majority of species listed are paracoprids and they are important species for pasturelands, but four of them are considered of the highest importance, those are: Dichotomius bos, Dichotomius nisus, Ontherus appendiculatus and Trichillum externepunctatum. I selected this species and used niche-based models and future climate simulations to predict their spatial distribution on 2050 and 2070 considering the RCP 8.5 emission scenario. My findings show radical reduction in the spatial range of dung beetle species, especially in recently opened areas, e.g., the Amazon region. I suggest that the consequences of these species’ spatial retraction will be correlated with ecosystem services depletion under future climate conditions, urgently necessitating pasture restoration and parasite control. According to data related to the introduction of Digitonthophagus gazella in South America, the introduction of new alien species is not encouraged. Additionally, I discuss that a gap of information on natural history of South American dung beetles prevent their conservation to be effective. The dung beetle species native to South America, here listed, have economic and environmental relevance on sustainable livestock production and their conservation should be prioritized.