Grazing cattle, deer, ponies and pigs are treading pathways that are helping rare species of animals and plants to thrive in the Purbeck Heaths National Nature Reserve. Those are the early findings from fieldwork by Bournemouth University.
For over 10 years, teams of students have been working on a project led by Professor Anita Diaz in collaboration with the National Trust, Natural England and the RSPB on the Purbeck Heaths to monitor habitats and support conservation efforts in the area.
Last year they began exploring the tracks trampled down by large herbivores which were released into a fenced, one thousand-three-hundred hectare, section of the heath landscape.
“We are hoping that the grazing cattle, pigs and ponies – as well as the resident silka deer – will create ecological corridors as they walk around and graze, and that these corridors will help other species move around the reserve,” said Professor Diaz Isla.
“As the animals move through the landscape they create a lot of disturbance by trampling and foraging,” added Ellen Baugh, an undergraduate student studying Ecology and Conservation. “They also create a lot of variation in vegetation which is important to a lot of species.”
The Purbeck Heaths have a large population of the rare silver-studded blue butterfly which is thriving thanks to this variation.
“These butterflies need really short, grazed heather as caterpillars, and taller tussocks to roost on as adults. The grazing herbivores provide this for them,” explained Ellen.
The small, carnivorous sundewSpecies of plants taking advantage of the animal tracks include yellow flowered bog asphodels which provide pollen for bumble bees and carnivorous sundews, which use their sticky red tentacles to trap insects such as ants and grasshoppers. “These plants are bare ground specialists which need a lot of light to survive. They don’t cope well with competition as they are so small and they are really making use of the paths that have been trampled and grazed down low,” Ellen explained.
During their surveys, the students have seen many signs of other animals making use of the paths, including the burrows made by invertebrates and sand lizards.
The university team has recently started a new aspect to the project, attaching GPS tracking devices to cattle to monitor their movements around the heathland.
“We’re interested in exactly how the cattle are behaving – such as how much space are they using, what habitats are they using for foraging, what habitats are they using for travelling,” said Tom Major, Postdoctoral Research Fellow in Animal Biotelemetry who is leading this work. “This will help us understand more about how they are contributing to the diverse set of habitats on the super national nature reserve,” he added.
The team hope that the long-term impact of releasing cattle into the nature reserve will reduce the need for human intervention in maintaining the balanced ecosystem needed for the many species that live there.
“Traditionally these heathlands have been managed by people. The hope is that the cattle, ponies and pigs that have been released here will do that work for us, helping to conserve the habitats for rare species like sand lizards, smooth snakes and lots of insects and plants,” Tom concluded.
The project has been supported by the Dorset Area of Outstanding Natural Beauty Sustainable Development Fund, National Trust and Bournemouth University.
