Farmers are trialling the use of livestock to control bracken without chemicals, with an ultimate aim to save costs while restoring habitats.
By trampling bracken, livestock are set to help knock back this invasive species which spreads across grazing land, restricts public access and suffocates other habitats.
If too dense, it threatens the habitat of the UK’s most endangered butterfly, the High Brown Fritillary, which is present on one of the trial farms.
Many farmers used to manage bracken with the herbicide Asulox, but this is no longer available, so some are now exploring other options.
Cattle, pigs and ponies across eight farms in Cumbria, Lancashire and Yorkshire are being encouraged to enter areas of bracken with methods such as strategically placed hay or salt licks.
The animals trample the bracken using their natural body weight, opening up space for other plant species while also damaging the bracken fronds and restricting regrowth.
The pigs also root out the starch-rich rhizomes of the bracken from below ground.
Triallist Katharine Pinfold, a farmer at Hudson Place Farm, Cumbria, has substantial area of bracken on the fellside which limits the grazing available for livestock, as well as general biodiversity.
She said: "Our farming system is very low input and therefore using our Belted Galloway cattle as a means of controlling the bracken seems to us an obvious nature-friendly solution.
“It is great to be working in a group with other farmers to measure and monitor the impact of livestock on bracken density and growth.
"We are also excited to see what other plants will emerge over time as the bracken cover recedes.”
In some parts of the country, particularly in the west, bracken stands maintain a woodland ground flora, allowing plants like dog violets to grow which are a key food source for caterpillars of fritillary butterflies.
The trial therefore doesn’t seek to eradicate bracken entirely, but to maintain a balance and "mosaic" of habitats, providing opportunities for a range of biodiversity.
The group of farmers, who are trialling as part of an Innovative Farmers initiative, are working with experts at James Hutton Institute to monitor changes to habitat.
They hope to find a long-term solution that uncovers grazing land while also boosting nature.
Soil health will be monitored, with samples lab-assessed for their carbon and nitrogen contents as well as carrying out visual soil structure assessments.
Field lab researcher Robin Pakeman of the James Hutton Institute said it was a "great opportunity – we haven’t had a trial like this for decades".
He said: "Asulox herbicide could be sprayed over large areas and, if followed up properly with repeat spot spaying, could be very effective. However, it is no longer available, so we have to think differently.
"Using livestock means we can hopefully manage with more precision to achieve different impacts across a stand of bracken.
"We’re monitoring the trial closely and hoping for a long-term boost for biodiversity.”
