A NEW Zealand dung beetle specialist wants Environment Southland (ES) and other regional authorities to do more to help farmers establish populations on their farms.
Invertebrate ecologist Dr Shaun Forgie, of Auckland, said regional councils should be releasing more trial colonies and allocating money for dung beetle purchase subsidies.
“My [view] is regional councils should be subsiding dung beetles just like they do for other waterway protection measures such as riparian planting and fencing.”
Dung beetle larvae devour animal dung. Female dung beetles make dung balls, tunnel down into the ground and lay an egg into each dung ball. Hatched larvae eat their dung ball as they grow, turning it into a sawdust-like material which becomes a soil fertiliser.
If the beetles were widespread, their efforts would reduce the amount of effluent polluting waterways, Dr Forgie said.
Dung beetle activity also improved soil health and aeration, reduced water and nutrient run-off, and encouraged grass roots to grow deeper into the soil, making pasture more drought resistant.
Dr Forgie has been breeding dung beetles since 2011, when the national Dung Beetle Release Strategy Group was given permission to import 11 species of beetles from several countries. In 2014 he became a principal in Dung Beetle Innovations, a company which sells beetles commercially.
He said ES and the Wellington Greater Regional Council had been “the two most progressive councils in the country”, both releasing trial colonies early on.
In 2013 and 2014, 1200 beetles were released at five Southland locations. However, Dr Forgie said “things had gone quiet” since, and he did not want Southland to lose its momentum in building up populations.
Last year, Dung Beetle Innovations sold beetles to two Southland farmers, he said. One was a “whole farm package” comprising six colonies of three species, while the other was a one-species “starter package”.
ES senior biosecurity manager Randall Milne said monitoring earlier this year had not revealed any beetles at the trial locations yet and ES would need proof the trial populations had established before deciding whether to invest more money.
He said not locating any beetles was not unexpected, as it could take up to five years for the species released in Southland to become visible above ground.
“It doesn’t mean they are not there, it just meant they didn’t turn up when we went looking for them.”
Mr Milne said it was possible ES could invest in dung beetles, as it already invested in other biological weed control agents such as seed weevils, which ate Darwin’s barberry, and gall mites, which destroyed broom.
About $9000 was budgeted for biological weed control this year.
However, he said subsiding dung beetles “hadn’t been brought up by anyone in the community” yet.
ES chairman Ali Timms said she favoured joint discussions between ES and industry groups such as Federated Farmers and DairyNZ.
“Dung beetles are another tool in the toolbox… and it would be worthwhile getting together and discussing the best approach.”