Our work in the Calstone and Cherhill Downs

Written by

Keith SteggallWild Landscape Ranger, National Trust

View towards the Lansdowne monument of the rolling green hills at Calstone and Cherhill Downs in Wiltshire — View towards the Lansdowne monument | © National Trust Images/Rachael Warren

Calstone and Cherhill Downs is an outstanding area of chalk grassland habitat covering 202 hectares. An array of butterflies, orchids and rare insects call this unique habitat home but it’s thanks to a careful balancing act between livestock grazing and species conservation that you can easily see species like the adonis blue butterfly and rare orchids.

Working as a ranger at Calstone and Cherhill Downs

Part of the role of the ranger for the area is to keep a close eye on the condition of the site to make sure that management is working and that species are thriving.

At Calstone and Cherhill Downs we’re privileged to look after a fantastic habitat for a wide range of species of grassland insects and flowers as well as the birds that feed on them.

We work very closely with our own wildlife and conservation advisors as well as Natural England and the tenant grazier to ensure that an appropriate grazing plan is designed to support and improve the diversity of species on this site.

Cattle graze a broad range of plants and discourage the development of rank vegetation and scrub, allowing the natural chalkland species to thrive.

We make regular checks and record key species to monitor how well they’re doing from year to year, and this enables us to adjust our management plans where needed.

Monitoring key species

With such an extensive landscape and vast amount of species of flora and fauna, monitoring the health of it as a whole is quite a daunting undertaking. The way we do it is to pick out key species and use them as a barometer for the whole of the downs.

Butterflies

Butterflies are a good indicator of the condition of chalk grassland as they are dependent upon the right flora for their larvae. We’re fortunate to have a volunteer who goes out to record butterfly species around the downs from May through to September. Over the last few years, it’s been great to see the marsh fritillary is doing so well: back in 2008 we were recording fewer than 20 butterflies but since then numbers have risen so that we’re now recording them in the hundreds.

It’s also a good spot to see the adonis blue butterfly: there’s a strong population and it feeds on the horseshoe vetch that grows in abundance. Getting the grazing right to provide good habitat has been key to helping these butterflies to thrive here.

Wart biter bush cricket

The rarest species we’ve found in the Calstone coombes is the wart biter bush cricket and it’s only found at four other sites in the country. A delicate balance is required for this species: it needs bare ground for egg laying, areas of short turf with a diverse flora, but also a varied sward structure with areas of longer grass as cover from predators such as kestrels.

A survey is done each year in late summer which counts the number of males by locating them by their call or stridulation, this is the only way to find this elusive species.

This species was rediscovered here in the early 1990s when its survival was in doubt and since then, with careful management, it has recovered so that now it has a stable population covering an ever-expanding area.

Orchids

We have several orchid species on the downs, most of which are present in good numbers and so no formal recording happens each year. Our rarest orchid is the burnt tip, found in one location on the western down in late May and in very low numbers. Management of the downs ensures that the cattle aren’t grazing whilst the orchid is in flower to help it survive.

Tor grass

A threat to the chalk grassland habitat is the presence of tor grass, a dense, rough grass which smothers other flora and which the cattle don’t like grazing. The extent of tor grass is monitored by taking fixed-point photos.

Some targeted grazing with cattle one autumn on one of the banks looks to have produced some good results in opening up the grassland, this is something that will continue and will hopefully create even better habitat for chalk grassland species.

Late evening light in the coombes at Calstone and Cherhill Downs, Wiltshire | © National Trust Images/Emma Weston

Visitors and volunteers

In addition to looking after the environment, we also make sure that the site remains open for visitors, that pathways are maintained, fences are stockproof and gates and stiles are safe.

Volunteers monitor the condition of the hillfort so that we can take action to repair any areas of erosion and prevent further deterioration.

We also act as a main point of contact for any queries or concerns and can be contacted via email.

The best job

It’s a real pleasure to look after special places in the Wiltshire landscape. I get a great sense of fulfilment from working alongside volunteers on work such as cutting scrub or mowing barrows to maintain and protect them. Working on projects to improve the nature conservation and appearance of the places you look after is really motivating.

Seeing the changing seasons and the wildlife that comes around each year on the chalk grassland lifts the spirits - my personal favourites are listening for the sound of skylarks, the sight of Adonis blue and marsh fritillary butterflies and the amazing flowers that thrive on the downland. The views, both natural and historic, are incredible.