SECONDARY SEED DISPERSION BY DUNG BEETLE (COLEOPTERA: SCARABAEINAE) IN CERRADO
Coprophagous beetles; Vertical dispersion; Horizontal dispersion; Brazilian savannah; Scarabaeidae; Ecosystem Service
Ecosystem services are natural processes that society depends and benefits to survive. Among the services provided by dung beetles, secondary dispersal of seeds, a very important step in the life cycle of various plants, stand out. By burying feces mixed with viable seeds, these are moved to places with more favorable conditions for germination and seedling establishment, which can also help in habitat restoration. Since secondary dispersal is directly influenced by the species, functional group, and beetles size, as well as by seed size and burial depth, this work aimed to assess the contribution of beetles in secondary seed dispersal in the Cerrado, evaluating metrics of beetle community that provide this service, the vertical horizontal seed dispersal, and the effect of seed size on dispersal. For sampling and community characterization, pitfalls baited with human feces were installed in two areas of cerrado sensu stricto. Experimental stations with baits containing plastic beads of two sizes were used to assess vertical and horizontal secondary seed dispersal. This work proposes the use of five variables to evaluate secondary dispersal, considering the participation of the dung beetles in dispersal both below and above ground, a relevant aspect from the point of view of both plants and secondary dispersers. The experiments took place during the rainy season from November 2020 to January 2021. Our results show that paracoprids are positively associated with horizontal dispersals of small beads above ground and negatively associated with vertical dispersal of large beads below ground. These data are controversial because large paracoprids were expected to tunnel deeper and more complex in tropical and open Cerrado environments. Thus, paracoprids occupy the most relevant role for secondary seed dispersal in Cerrado. The dominance of Oxysternon palemo demonstrates the relevance of this species in the restoration of the Cerrado, especially of the cerrado sensu stricto physiognomy, because the species can show resource allocation behavior. There was no significant response about the vertical dispersal above ground, however, we reinforce the potential protection that V1 can provide to seeds. We also found a negative relationship between large paracoprids abundance and vertical dispersal below ground of large beads. Habitat alteration can interfere with the functional richness of dung beetles, leading to different responses when analyzing the provision of ecosystem services. Therefore, strategies involving the reintroduction/maintenance of dung beetles and mammals favor habitat restoration due to seed dispersal, mainly of native species.