Carbon Neutral: The Failure of Dung Beetles (Coleoptera: Scarabaeidae) to Affect Dung-Generated Greenhouse Gases in the Pasture

Abstract

Research suggests dung beetles can churn, aerate, and desiccate dung in ways that influence the dung and soil microbes producing greenhouse gases (GHGs). We examined the impacts of the tunneling beetle, Onthophagus taurus (Schreber), and the dwelling beetle, Labarrus pseudolividus (Balthasar), on the carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emitted from pasture-laid bovine dung as well as their sum-total (CO2 + CH4 + N2O) effect on global warming, or their carbon dioxide equivalent (CO2e). Despite dung beetles potential effects on CH4 and N2O, the existing literature shows no ultimate CO2e reductions. We hypothesized that more dung beetles would degrade pats faster and reduce CO2e, and so we increased the average dung beetle biomass per dung volume 6.22× above previously published records, and visually documented any dung damage. However, the time effects were 2–5× greater for any GHG and CO2e (E = 0.27–0.77) than dung beetle effects alone (E = 0.09–0.24). This suggests that dung beetle communities cannot adequately reduce GHGs unless they can accelerate dung decomposition faster than time alone.

Recarbonizing global soils: A technical manual of recommended sustainable soil management

“…Above-ground dung greenhouse gas (GHG) dynamics (CO2 + CH4 + N2O emissions) have been reviewed by Fowler et al (2020) (11 papers considered). They concluded that there was no evidence for ultimate CO2e reduction due to dung beetle activity.…”

Seasonal Variation in the Organization of Dung Beetle Communities in the Moroccan Middle Atlas (Coleoptera: Scarabaeoidea)

“…Factors affecting their abundance and distribution thus impact dung degradation [1][2][3][4]. Their activity directly improves the fertility and physical characteristics of soils [5], helps to disperse seeds contained in dung [6], contributes to the reduction of dung breeding flies and gastrointestinal parasites of livestock [1,7], and in part reduces greenhouse gas emissions [8][9][10]. Three main guilds have been identified to describe the feeding and/or nesting behavior of dung beetles: non-nesters (dwellers), paracoprids (tunnelers), and telecoprids (rollers) [11,12].…”

Diversidad de escarabajos coprófagos (Coleoptera: Scarabaeidae) en tres zonas urbanizadas del Caribe colombiano

“…En este contexto, los escarabajos coprófagos se han seleccionado como un buen modelo ecológico para evaluar el impacto de la urbanización sobre la biodiversidad, debido a su papel funcional dentro de los ecosistemas (Andresen 2001, Nichols et al 2008, Arriaga et al 2012. Las especies de la subfamilia Scarabaeinae (Scarabaeidae), reconocidos cómo verdaderos coprófagos, actúan como descomponedores de la materia orgánica y reincorporadores de nutrientes al suelo, así mismo, contribuyen a la aireación, favorecen la penetración del agua, y a la diseminación de semillas (Nichols et al 2008) e inclusive, bajo ciertas condiciones, ayudan a mitigar el efecto de los gases invernadero producidos por la ganadería (Fowler et al 2020). Adicionalmente, reúnen características de grupos indicadores como su sensibilidad a los cambios en el medio ambiente, fácil recolecta a través de métodos estandarizados, taxonomía relativamente estable y distribución e historia natural conocidas (Halffter & Favila 1993).…”