Demonstrating the benefits of dung beetles to prime lamb producers

Summary

The Enhanced Producer Demonstration Site (EPDS) concept was developed in 2014 as a partnership between Meat & Livestock Australia (MLA) and Agriculture Victoria. The partnership brings the benefits of integrating with Agriculture Victoria’s  BestWool/BestLamb and BetterBeef network of producers and groups receive assistance from Agriculture Victoria extension staff throughout the demonstrations including monitoring, evaluation, reporting and communication.

This project comprised of two parts. Firstly, the completion of a suite of eight (Phase 1) demonstrations that commenced in 2014, and secondly, a further seven (Phase 2) demonstrations, established through an expression of interest (EOI) process that commenced in 2018 / 19. 

Investigating the presence of dung beetles in southwest Victoria and demonstrating their benefits in prime lamb operations.

Objectives

The aim of this project was to demonstrate the benefits of dung beetles in a sustainable sheep farming system in southwest Victoria and to explore if these benefits can be utilised to add value to modern prime lamb operations.

More specifically, the project aimed to: 

1. Investigate what species of dung beetles are active on sheep dung in southwest Victoria and their seasonal patterns of abundance.

This was achieved through monthly trapping across a total of eight properties, each for twelve months. 

2. Demonstrate the impact that dung beetles have on soil health and fertility, including through burial of dung infused with biochar. 

The impact on soil fertility of Bubas bison was demonstrated across four different soil types/ sites. However, the impact of biochar was not successfully demonstrated.

3. Increase producers’ knowledge of the role of dung beetles and improve skills and confidence in managing dung beetle populations.

The group averaged an increase in knowledge from 3.7/10 to 7.3/10 and an increase in skills from 4.2/10 to 6.7/10. There was also adoption of monitoring and practices to encourage dung beetle populations. 

Key findings

Twelve species were trapped, using sheep dung, across the eight properties including introduced Bubas bison, Euoniticellus fulvus, Euoniticellus pallipes, Onitis aygulus, Onthophagus binodis and Onthophagus taurus, as well as native Onthophagus australis, Onthophagus mniszechi, Onthophagus posticus and Onthophagus auritus. Two dung dwellers (not true dung beetles) were also found; Aphodius fimetarius, Aphodius lividus.

O. taurus and E. fulvus were the prolific species and are active over the warmer months. A noticeable gap in introduced dung beetle abundance was observed from late autumn to early spring, however the native O. mniszechi was active year-round at Cashmore, Narrawong and Heywood.

Large increases in phosphorus and potassium were measured to depth through the action of deep tunnelling Bubas bison. The additional phosphorus measured at 10-30cm depth in the Dung+Beetle plots was equivalent to around 1 t/ha of single super valued at approximately $650/ha (not spread).
The additional potassium at 10-30cm equated to between 150-430 kg/ha of applied potash valued at approximately $200- $470/ha (not spread).
High numbers of earthworms were observed under Dung+Beetle plots, including earthworms that had wrapped around the tunnels of dung. It is likely that this increased activity is from earthworms feeding on buried dung.

Project extension involved two public field days and a webinar as well as presentations, numerous media articles and two social media posts promoting the project results. A case study and project summary were also developed. Factsheets were produced for dung beetles trapped throughout the demonstration and have proved popular, with 565 webviews at the date of reporting. These activities led to a large, measured increase in the group’s knowledge and skills, and adoption of dung beetle monitoring activities as well as members indicating they planned to purchase dung beetle colonies to build populations.

Benefits to industry

The project showed that dung beetles are active on sheep dung in southwest Victoria, particularly over the warmer months from late spring to early autumn. It identified that a gap in abundance exists in the cooler months from late autumn to early spring and there is an opportunity to fill this gap through the introduction of winter active species such as Bubas bison. The dung burial trials
demonstrated the impacts of dung beetles on soil health and fertility. This  information adds to the limited available information about dung beetles in sheep systems and can be used to further communicate their benefits.

Future research

There is scope to increase the populations of winter active dung beetles such as B. bison in southwest Victoria, however more guidance on how to effectively do this would be beneficial given some group members had attempted releases and beetle rearing with mixed success. Furthermore, the project led to producers asking for more information about the impact of drenches on dung
beetles and methods for managing drenched animals to minimise impacts on dung beetle populations.