DUNG BEETLES   IN THE SOUTH WEST OF WESTERN AUSTRALIA

Dung beetles - delivering ecosystem services that improve grazing productivity

(2014-2017)

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Dung beetles - delivering ecosystem services that improve grazing productivity seeks to establish eight sites across Warren Catchments Council region, reflecting the variety of soil types and rainfall zones, to provide a range of paddock-scale contexts, as recommended by MLA, in response to the results of the small scale trial they commissioned Dr Bernard Doube to conduct (2007-8): The pasture growth and environmental benefits of dung beetles to southern cattle industry.

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The impact of dung beetles’ tunnelling and carbon storage on soil physical and chemical characteristics, soil biology, pH and EC and pasture growth will be monitored.

Education of local farmers and the wider community on dung beetle characteristics, identification and monitoring techniques will be supported by DAFWA entomologist, David Cousins and Dr Doube of Dung Beetle Solutions Australia.

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An interactive webpage on Warren Catchments Council’s website will enable local (WCC region) survey data to be input, generating an inventory of locally occurring species: density, location, time (date, season), species, manure source. This data will add to existing DAFWA survey results (2012-14) and assist CSIRO select release sites for newly imported spring active species (Onthophagus vacca and Bubus bubalus).

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Project Aims

Dung beetles - delivering ecosystem services that improve grazing productivity extends the outcomes achievable in the recently awarded State NRM grant to introduce Bubus bison to a large Northcliffe dairy where the 1000 head herd will be fed biochar on a daily basis and the dung beetles incorporate the char-manure into the soil to a depth of 60cm. This application was based on the independent research by Manjimup farmer, Doug Pow, who, after 12 months of allowing his beef cattle to free-feed a set quantity of biochar lick, had significant increases in nutrient availability and pH. This project will enable a more extensive collection of longer-term data across a wider area and involve additional dung beetle species.

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This project provides paddock-scale replicates to evaluate and quantify dung beetles’ proven capacity as a low cost biological mechanism to inter organic matter up to depths of 60cm+; and the degree to which they are responsible for:

• elevating levels of nitrate, ammonia, phosphate, sulphur (through cycling of macro and micro-nutrients leached to the subsoil)

• increasing pH, EC, SOM

• increasing earthworm and other soil biology populations that contribute to

• improving soil structure - increasing rainfall infiltration, aeration, moisture and nutrient retention and reducing compaction  

• It is anticipated an incrementally increasing dung beetle population will build perennial pasture resilience due to the buffering effects of increased SOM, enhanced nutrient balancing effect of soil biota and reduced acidity, lessening the need for chemical pest control and veterinary chemicals.

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The project seeks to:

• monitor beetle presence, activity, distribution and colonisation to increase reliable data of locally  occurring dung beetle species

• provide landholder anecdotal observations and calculations about the cost-effectiveness of dung beetles

• build knowledge within the farming community to understand beetle colony value within the farming system 

• increase understanding of land management practices that protect and enhance beneficial dung beetle and soil food web functioning

• encourage and facilitate local beetle collection and distribution once colonies are established.

 

Trial design

Hypothesis:

Dung beetles are an effective means of delivering ecosystem services that improve soil condition.

Primary question:

What are the specific impacts of dung burial activity by Bubas bison and other dung beetles on soil condition (physical, chemical and biological characteristics) across a range of soil types?

Secondary questions:

What colonisation patterns (population, distribution and activity duration) are evident across a range of soil types?

Trial Sites

Eight sites will be dispersed across the Warren Catchments Council zone; the project will be based on cattle properties in Walpole, Northcliffe, west Manjimup, Chowerup, Perup and Quinninup areas. Trial paddocks will be limited to 5 hectares with a minimum of 50 head of cattle grazing on rotation in adjacent paddocks throughout the active life cycle of the released beetle. [Enhances beetle opportunity to access adequate food source and, when mature, find a mate.] This site will be the main venue for determining data relating to beetle activity.

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Three monitoring traps are located 50m apart adjacent to paddocks frequently used by cattle to enable year-round data collection.

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Data relating to the residual effects of beetle activity on soil characteristics after three years will be derived from the use of three “exclusion” 1m2 frames, each separated by one metre. The control will be one exclusion frame site. The other two exclusion sites (under the frames) with be manure or manure plus beetles. (see trial design)

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Soil types will vary but sites will be selected upon those soil types known to be conducive to tunnelling dung beetle colonisation, ie contain some clay.

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Vegetation dominated by perennial species, summer and winter active, will be selected (provides optimal conditions for beetle persistence and microbial activity). It is acknowledged these pastures will vary across sites.