Dung beetles play valuable role in grassland management (Farmers Weekly)

Gemma Claxton

Monday 10 August 2015

Livestock farmers walk past piles of cow pats or

sheep droppings every week, but when was the

last time you took a closer look? Gemma

Claxton investigates the importance of dung

beetles.

Rapid and thorough dung decomposition can have

significant benefits for soil nutrients and structure,

while also increasing the area available for grazing

livestock.

Sarah Beynon, founder of Dung Beetles Direct, says in

England an estimated 161,826ha or 4.8% of

permanent pasture could be lost from production each year if cattle dung alone is

not broken down.

Pic. Dung

beetles. Oct 15 (Rob Yorke)

See also: Grassland management revival boosts sheep output

“In the UK, we have over 40 species of dung beetle. By feeding-on, breeding-in,

shredding and burying dung, dung beetles can efficiently break down dung, which

can deliver significant benefits to farming businesses.”

Heading up a recent Farming Connect dung beetle project, Dr Beynon organised a

pilot release of nearly 2,700 beetles at set points throughout the spring and

summer on three farms. The benefits of dung beetles included:

Faster dung breakdown which increased the amount of available pasture for grazing

Increased soil nitrogen which reduced the need for artificial fertilisers

Higher pH which reduced the need for lime

Increased soil P, Mg and K, which improved soil nutrient availability

Peter Williams: Great House Farm, Llansoy, Usk

Beef and sheep farmer, Peter Williams, who took part in the trial, admits he didn’t

think he had any problems.

The trial at Great House Farm, Llansoy, Usk, involved fencing off a 20sq m area in

a paddock so livestock could not access it. Dung beetle numbers were assessed

using dung baited pitfall traps during a one-week period.

“After my attention was drawn to it, I noticed particularly on dry ground, the dung

was not being broken down.”

The results showed existing dung beetles at the farm were increasing rates of

dung breakdown by 46% in spring, 4% in summer and 31% in mid-summer on

average.

Dr Beynon’s top tips for sustainable worm use to preserve dung beetles

Only treat animals with a proven parasite burden; use faecal egg counts and blood tests

Keep livestock indoors and off pasture for at least 72 hours post-treatment if possible

Try to use chemicals less toxic to dung beetles when animals are at pasture

Weigh animals to prevent under dosing

Use additional strategies for example rotating pastures and resting them for a minimum of

three weeks

Create a parasite control plan with your vet

However, after the additional dung beetles were released (2,500 in spring, 100 in

early summer and a further 100 in mid-summer), dung breakdown increased by

an additional 134% in spring and 13% in early summer on average.

But the benefits are not always visible, says Mr Williams. In spring, phosphorous

soil levels were higher under dung pats with dung beetles than without (with =

50mg/litre, without = 45.5mg/litre) and the same was true in early summer (with

= 43.5mg/litre, without = 34.5mg/litre).

Mr Williams has also altered his worm control protocol by reducing the amount of

ivermectin used, as drenching with this chemical can kill the beetles.

“I had no idea how important dung beetles are until taking part in this trial, but

without them we can’t go on. If you can’t get muck into the ground you can’t grow

anything.”

Mr Williams’ next step is to monitor the fields to see if the population has

increased and he hopes, in future, savings can be made by reducing the amount

of fertiliser required.

Dung beetle decline

“As long as farm management practices don’t kill the beetles, the population

should increase year on year, delivering more benefits,” says Dr Beynon.

However, dung beetle numbers are declining, she warns. Dr Benyon puts this

down to changes in agricultural practices, intensification and the associated

treatment of livestock with certain wormers, which are toxic to the beetles. 

“I believe the decline is largely due to more intensive patterns of anthelmintic and

ectoparasiticide treatment of livestock, as well as fewer grazed, old, unimproved

pastures and the upsurge of the short-term ryegrass monoculture.

“Chemicals that are toxic to dung beetles should not be routinely employed when

livestock are at pasture, but selectively used and, if possible, used instead during

housing, so the toxic dung does not come into contact with dung beetles.”