A case study from Tarnhouse Farm
by Ian Ryding, farmland warden
Tarnhouse Farm is one of two large upland farms in the North Pennines that form RSPB Geltsdale Nature reserve. It comprises areas of moorland and acid grassland, grazed by hardy native-breed cattle for the benefit of wildlife. The reserve also has remnants of ancient grazed woodland, notable for its veteran trees and dead wood. This supports a rich assemblage of specialist insects, fungi and lichens, as well as nesting, roosting and foraging sites for bats and birds. To extend this habitat and bolster native trees and scrub across the farm, we have carried out low-density planting in several areas, avoiding deep peat and where it may impact breeding waders.
During the winters of 2004 and 2005 we planted around 250ha of open fell ground at 240-450m with around 110,000 native trees – a mixture of sessile oak, birch, rowan, ash, alder, willow and hawthorn – to create the Bruthwaite woodland. This new woodland stretched into the next valley to connect with the fragments of ancient woodland pasture.
I have worked at the site since 2006 and have found it fascinating to see this area develop from tightly grazed sheep fell into a diverse scrub woodland habitat, benefiting an abundance of wildlife.
Varying topography, soil conditions and exposure to the elements has meant the trees have grown in a diverse manner. Some areas now look like established woodland while elsewhere trees are still struggling to leave their shelters, especially higher up the fell. The ground layer vegetation is also very diverse, comprising acid grassland with patches of heath, bilberry, greater woodrush, bracken, rush and sedge species. This provides excellent cover and feeding opportunities for black grouse, a priority species on the reserve.
The establishment phase of new woodland, prior to maturity and closed canopy, is valuable to many species; continuing to benefit species associated with open fell ground whilst also attracting woodland edge species. In the Springtime, the developing open woodland is alive with the sound of willow warbler, who along with pied flycatcher, whinchat, redpoll and cuckoo have clearly benefited.
Prolonging this phase is a priority for the reserve, and so it was always the intention to introduce cattle grazing into the establishing woodland to retain open areas. With appropriate management, cattle benefit woodland ecosystems. They create disturbance and structural diversity, recycle nutrients and distribute seeds; they are key to introducing natural processes. Open woodlands also provide cattle with a varied diet, shelter and stimulation.
Grazing cattle in woodland
With funding from the North Pennines AONB, we chose to trial an invisible fence system as a way of breaking up the large area. If successful, it would avoid the challenge of installing and maintaining standard fencing amongst rough vegetation in steep terrain. Regular fencing can also be problematic for bird species such as black grouse which can get caught up in the wire and perish.
The Nofence virtual GPS fencing system: A grazing area is mapped on a mobile phone app, which communicates the coordinates via 2G signal to solar powered collars fitted on the livestock. As the animal approaches the grazing boundary, the collar plays an audible melody. If the animal continues to move towards the boundary, the volume and pitch increase and finally emit an electric pulse. Animals quickly learn to recognise the sound and turn back to avoid an electric pulse. The herd can be monitored daily via the app which tracks the cows’ movements, monitors battery life and alerts to any issues or escapees.
In September 2020, we fitted nineteen 15month old Luing heifers with GPS collars and spent a few days in a field getting accustomed to the system. It was fascinating to see how quickly they learned to recognise the warning sound and turn around. The leaders of the herd would test the boundary frequently, while others hung back, ears aloft, responding to the wariness of the lead cow. It was reassuring to see animals grazing again, tail swishing, within seconds of a pulse.
Following training, we introduced them to a 32ha enclosure of the Bruthwaite woodland - the first livestock grazing on this land for 15 years. In the early years, the plan is to pulse graze areas of the woodland through the autumn & winter months.
Invisible fencing showed clear benefits
Over the trial period the collars were tested in some extreme conditions. Despite some collar failures which were put down to water ingress (since modified), the herd stayed together inside the Nofence enclosure. We also achieved our grazing objectives. We moved the herd around to prevent overgrazing of the dwarf shrub layer, an important food for the black grouse. Some areas remained ungrazed. The cattle did a great job trampling stands of bracken, especially under trees. Cows were very contented in their woodland grazing, enjoying the shrub flora and tree leaves. They especially gorged on hawthorn berries. The cattle maintained good body condition without any feed supplementation. Nutritional analysis has shown the leaves of most tree species to be as good as meadow hay. By late December, battery life was running low in the short dim winter days and a handful of collars were failing to report.
In Spring 2021 we tested another conservation use for the Nofence GPS system by ‘fencing off’ and protecting some curlew nests within a grazing block. It has many potential applications for conservation and commercial grazing systems. Another benefit for the reserve was the ability to keep cattle away from our main visitor trails and footpaths.
There are ambitious targets for woodland planting across the UK. This work highlights how this need not be a binary choice between woodland or livestock. Instead, there can be shared benefits for climate, wildlife and livestock from integrating trees and farming in appropriate places.
More about Geltsdale reserve: https://www.rspb.org.uk/reserves-and-events/reserves-a-z/geltsdale/
Wood pasture wildlife (PTES) https://ptes.org/campaigns/wood-pasture-parkland/wildlife/