Tunneling Dung Beetle Effects on Soil Microbial Communities and Nutrient Cycling in Pasturelands: Implications for Soil Carbon Dynamics

Abstract

ABSTRACT

Intensifying the management of grazed pasturelands can lead to higher greenhouse gas emissions, loss of biodiversity, and a general decline in ecosystem function. Yet, maintaining the abundance and activity of soil organisms, such as dung beetles, in pasturelands may improve soil ecosystem function. The tunneling dung beetle, Onthophagus taurus (Schreber 1759) buries dung in the soil, affecting soil physical properties, the soil microbial community, as well as nutrient cycling. However, few studies have examined links between dung‐beetle‐mediated changes in soil microbes and soil organic carbon. We used a 60‐day enclosure experiment to examine how O. taurus affects the soil microbial community and soil organic carbon in pasturelands of California's Central Coast, and to examine whether any observed changes in the soil microbial community are beetle abundance‐dependent. Using eDNA metabarcoding of the prokaryote 16S and fungal ITS1 loci, we find that dung beetles affect the soil bacterial community only within surface soils (top 0–1 cm), whereas their presence affects the fungal community in both surface soils and in 0–10 cm cores. We also found that the fungal taxa more likely to occur in the presence of dung beetles are associated with carbon cycling. Despite these relationships, neither the presence nor abundance of dung beetles in pastureland soils had an impact on soil carbon content in the time of this experiment. Our results illuminate the influences of dung beetles on the soil microbial community and nutrient cycling in pastureland soils which can have broad‐reaching implications for ranchers and land managers.