Spotlight on Heather
For thousands of years the prominent position occupied by Wooston Hillfort has played an important role for both wildlife and the human species. Long before the Iron Age settlers, the look of this bulging spur of land has transformed from one era to the next. It has been the scene of numerous backdrops for different dramas that played out over the centuries. If you go there today, the expansive views across rolling Devon farmland to the east or the depths of the Teign gorge to the west evoke feelings of wonder from the vast and ever-changing landscape. Perhaps you may allow your eyes to drop from the distant horizons to take in the details of the hillfort itself, the intentionally undulating forms of the prehistoric ramparts. But only a few years ago, this important ancient landmark was swathed in conifer trees and choked with head-high vegetation and, since the Fingle Woods restoration began, these changes are continuing. Through late summer and into the autumn, the most obvious visual impact comes from the clumps, clusters and carpets of heather that are reclaiming their place on the exposed acidic soil. There are two species of low-growing, acid-loving plants we refer to as ‘heather’ on the hillfort. Larger areas are covered with the lilac coloured common heather (Calluna vulgaris) or ‘ling’ but, popping up in between, are vibrant rosy pink spikes of the bell heather (Erica cinerea) where small ‘bells’ hang in wait for the enthusiastic pollinators to do their work. In late summer, the hillfort is buzzing with life.
Erica cinerea grows in patches along tracksides Calluna vulgaris forms small bushy plants
But how did these heathers get here? Though a few small plants had been dotted along the edges of the standing conifers, since the felling of these dense timber trees, the lilacs and pinks have had a rapid renaissance. They do well in this poor soil, but the sunlight is key. In the shade of the mass of conifers the heather seeds would have been lying in wait; they cannot germinate in the dark. They were dormant for decades while the mixed conifer cover of Douglas fir, western hemlock and western red cedar covered the ground in the 20 years after being planted in 1993, but now, the planted conifer trees are gone and a brighter future awaits. Other areas of the woods around the moorland edge were probably heath before trees were planted so it is perhaps appropriate that they now become home to these species again. Heather clad glades and ride sides throughout the woods will add to the mix of plants and animals, providing the diversity required for a balanced ecosystem … but there may be a problem.
Heather recovers in the sun where conifers are thinned out
Adrian Colston who, in his former role as National Trust Manager for Dartmoor, played a vital part in the acquisition of Fingle Woods, is now researching the land use and ecology of the moor. In a recent lecture to the Dartmoor Society, he discussed the effects of increasing levels of atmospheric nitrogen from recent human activity and how its effects are reducing the growth of moorland heather. “Research has shown that heather will not be displaced by coarse grasses even under high levels of nitrogen deposition unless the heather is severely damaged either by weather conditions or defoliation by heather beetles. Heather beetle outbreak frequencies are also linked to enhanced nitrogen deposition. When this happens, the coarse grasses replace the heather and create conditions where the heather is unable to regenerate.
Conservationists need to take atmospheric pollution more seriously as it is a driver of change and not just an inconvenience and the two narratives of the Uplands need to be merged into one. We also need to campaign to improve air quality in the UK for both wildlife and people
When in ecological balance, the heather beetle (Lochmaea suturalis) and its host plants can co-exist. The heathers should be able to recover from the defoliation caused by the Heather beetle but, when atmospheric nitrogen favours purple moor grass, it is a different story. The Heather Trust is concerned, and states that, “This is a particularly significant cause of moorland decline in the wetter areas, generally on the west side of the country where there is often greater competition from grasses. Purple moor-grass (Molinia caerulea) is often the chief competitor.” This tussock-forming grass can be seen across the high moor as it tightens its grip on the upland vegetation. Often the panoramic sweep of purple heather moors and the associated wealth of invertebrates are becoming dominated by the pale, papery foliage that rattles a warning in the moorland breeze.
Many invertebrates benefit from a mosaic of moorland habitat
Here at Fingle, we can encourage a richer patchwork of habitats to form as the development of a new hillfort management plan is underway, aiming to support the diverse matrix of life. It may not necessarily be a woodland – heath is an important part of the mix, where species such as ground nesting birds can make their home, butterflies can find nectar and maintain their populations in a patch of optimum habitat. Alongside a programme of cyclical gorse cutting, pulling up birch seedlings and rolling of bracken, the ponies will play their part in grazing patches of vegetation and creating a varied sward alongside a line of trees for bats to forage and roost, clumps of gorse for interesting invertebrates, small trees for birds to perch and a scrubby patch for dormice to nest. Preserving the Scheduled Ancient Monument provides a perfect opportunity to conserve a number of wild species of plants and animals too. So, we look forward to a more diverse future and hold out a ray of hope for the heather.
by Matt Parkins
A full transcript of Adrian Colston’s 2018 lecture can be found here