Chalk grassland, with its colourful wildflowers and multitude of insects was once a common sight in a Dorset summer. It is the landscape defended by the Cerne Giant and where, in Far from the Madding Crowd, we first meet sheep farmer Gabriel Oak. In the 20th century, however, much of Dorset’s chalk grassland disappeared following changes in farming practice, although small areas survived, usually where ploughing was too difficult. So, when I heard about the visit to Higher Coombe, an area of chalk grassland above Litton Cheney, as part of the South Dorset Ridgeway Festival of Discovery, I jumped at the chance to see this ancient landscape and its exuberant floral displays.
We gathered near the entrance to Coombe Farm just off the busy A35. Despite this being only a few days away from the summer solstice, the sky was overcast and a cold, blustery wind cut across the ridge sending many of us to grab warmer clothing. The coombe fell away to the south, a deep gash in the chalk with precipitous grassy sides and extra folds and creases giving the landscapwe the look of a rumpled duvet. A farm track clung to the eastern side of the coombe and higher up, near Coombe Coppice, sheep dotted the hillside. Beyond the coombe, occasional shafts of sunlight illuminated the Bride Valley and its patchwork of green fields. The sea should have been visible but a distant mist had taken its place.
Local expert Nick Gray, from the Dorset Wildlife Trust, was our guide for the afternoon. He began by shepherding us through a farm gate on to the western slope of Higher Coombe to follow a rough contour along the hillside. Walking was difficult, there was no distinct path in the long, thick grass and the steepness of the hillside made it awkward to pause to observe. But there was plenty to see: architectural clumps of thistles with their purple mop heads, many different species of grasses and, where the turf became shorter, a mosaic of colourful wild flowers lighting up the hillside. My attention was drawn by the violet-purple splashes of wild thyme with its distinctive tubular flowers but Nick made sure we also noticed the tiny white trumpet flowers of squinancywort with their delicate pink stripes. The buttery yellow flowers of bird’s foot trefoil were also scattered about the hillside together with frothy lemon-yellow clumps of lady’s bedstraw and the delicate golden globes of black medic. A few lilac-mauve discs of scabious and pink-purple pyramidal orchids added to the display. These were just a few of the diverse plants growing here and it has been estimated that chalk grassland can support up to 40 different species of flowering plant per square metre. It is one of Europe’s most diverse habitats, the European equivalent of the tropical rain forest.
So, why is chalk grassland such a rich habitat? The soil that covers the underlying chalk hills is a great influence, as Nick explained to us. Thin, lime rich and nutrient poor, it holds little water especially on steep slopes and dries out quickly in the summer. These stressed conditions mean that lush grasses cannot dominate and a wide range of chalk loving species can flourish. Good management with controlled grazing is also essential to keep the turf short, stop scrub developing and at the same time allow chalk grassland plants to grow. The land on both sides of Higher Coombe is managed through a stewardship agreement with the farmer whereby, for about six months each year, grazing animals are excluded on one side. When grazing stops, the grassland explodes into flower and this year the western side is getting its chance. Next summer it will be the turn of the eastern side which will be ablaze with orchids.
With this profusion of flowers, I had expected to see many invertebrates but, that afternoon, there were very few flying. Bees in particular were scarce and we saw only two bumblebees all afternoon. Perhaps the cool air, the lack of sunshine and the encroaching sea mist were restricting their activity? We came across two large golden-ringed dragonflies resting among the vegetation on the hillside, unable to fly in these weather conditions. This did, however, give us the chance to examine these normally mobile creatures with their striking yellow bands on a black background. Later on, as we walked through another field on the eastern side of the coombe, we disturbed many small butterflies which seemed to be sheltering in the long grass. In part compensation for the lack of flying insects, there were some beautiful bee orchids and common spotted orchids on this second chalk hillside.
But should we care about the decline of this special and once common habitat? The loss of wild flowers will certainly have affected the beauty of our countryside, as well as contributing to the well-documented decline in insects and farmland birds. There is also evidence that florally-rich chalk grassland provides healthier forage for grazing animals as compared to contemporary feeding on heavily fertilised rye grass. Perhaps, had we been aware of the importance of the chalk grassland landscape, we might have valued it more?
If you want to see some of the remaining pockets of this special landscape then try Eggardon Hill or Maiden Castle or the Cerne and Sydling Downs or, further afield, visit Ballard Down in the Purbecks or Hambledon Hill and Hod Hill north of Blandford. Chalk grassland is glorious at any time of year but the best time for flowers is from spring until early autumn.
Philip Strange is Emeritus Professor of Pharmacology at the University of Reading. He writes about science and about nature with a particular focus on how science fits in to society. His work may be read at http://philipstrange.wordpress.com/