Dung beetles (Coleoptera: Scarabaeidae) can improve soil hydrological properties

Abstract

a b s t r a c tAlthough dung beetles are known to perform a multitude of ecosystem services, their effects on water infiltration, runoff, porosity, moisture and erosion of soil have never been thoroughly researched. Maintenance of these hydrological properties is important in agro-ecosystem functioning where overgrazing results in negative impacts on the soil. The study site was located in the Potshini catchment in KwazuluNatal (South Africa), an area heavily grazed by livestock. We conducted two rainfall simulations on three 1 m −2 control (no dung) and six dung-treated plots in December 2008, and repeated the study in June 2009 on the same plots. Natural populations of dung beetles were allowed to colonise the dung. Simulations were conducted for 30 min at an intensity of 30 mm h −1 . Key variables calculated were pre-runoff amounts (Pi), infiltration ratios (Ki), and soil losses. Samples were collected for bulk density determination during the same time periods in order to measure differences in porosity and moisture in control and dung-treated plots at different depths. Using multivariate statistics we found significant differences between dung-treated and control plots in three of four simulations. After 48 h of beetle activity, Pi and Ki values were significantly increased and remained at elevated levels six months later. Soil losses were initially higher in dung-treated plots than controls, but had declined to less than control values after six months. Bulk density in the A-horizon (0-10 cm) was significantly reduced after 48 h of beetle activity and remained so for six months. No difference in bulk density was observed at greater depths. Soil moisture initially increased significantly in the A-horizon, as well as at 20 and 30 cm depths after six months of activity. We conclude that dung beetles positively influence hydrological properties of the soil by increasing water infiltration and soil porosity, and reducing surface water runoff. Contrasting effects on soil losses are problematic to reconcile from this study. High losses initially observed may be offset in the long-term by reductions associated with the increased infiltration ratios, though this remains to be confirmed.

Scarabiasis: A rare infestation in humans

“…Temporary infestation of the digestive tract by dung beetles and 'flying away' from the anus at the time of the defaecation is termed Scarabiasis or Canthariasis 1 . In Scarabiasis, patients usually complain of loss of appetite, diarrhoea, cramps in abdomen and sometimes fever.…”

“…Dung beetles feed partly or exclusively on faeces and play a useful role in agriculture by burying and consuming dung, thereby improving the nutrient cycling and soil structure 1 . Temporary infestation of the digestive tract by dung beetles and 'flying away' from the anus at the time of the defaecation is termed Scarabiasis or Canthariasis 1 .…”

Comunidad de Escarabajos Coprófagos (Coleoptera: Scarabaeidae: Scarabaeinae) en Hábitats bajo Distinta Intensidad de Uso en Yuscarán, Honduras

“…Entre sus funciones más importantes, los escarabajos fertilizan el suelo (Bertone et al, 2006;Yamada et al, 2007), incrementando su aeración y porosidad (Brown et al, 2010). Son dispersores secundarios de semillas (Estrada y Coates-Estrada, 1991;Vulinec, 2002;Andresen, 2003), ayudan a promover el crecimiento del pasto (Bang et al, 2005;Arnaudin, 2012) y suprimen organismos patógenos del suelo en los pastizales (Doube et al, 1991).…”

Dung Beetles Associated with Agroecosystems of Southern Brazil: Relationship with Soil Properties

“…Studies have shown that physical and chemical soil properties affect the diversity, structure, and reproduction of dung beetles (Arellano et al, 2008;Martínez et al, 2009;Brown et al, 2010;Arellano and Castillo-Guevara, 2014;Farias et al, 2015;. Properties such as moisture content can promote the survival and reproductive success of some dung beetle species (Sowig, 1995;Martínez et al, 2009).…”