Malcolm Twigg Encounters Curlews, Butterflies., Tank Tracks and Fairy Shrimps on Salisbury Plain.

PUBLISHED: 15:04 14 January 2010 | UPDATED: 15:46 20 February 2013

Julie Swain of the DTE's Natural Environment Team, and Warrant Officer Les French

Julie Swain of the DTE's Natural Environment Team, and Warrant Officer Les French

Tank training on Salisbury Plain benefits the wildlife, strange though it may seem, but it needs managing.

Malcolm Twigg Encounters Curlews, Butterflies., Tank Tracks and Fairy Shrimps on Salisbury Plain.

On the face of it, there would not seem to be much linking an enormous and heavy Challenger II tank with the tiny fairy shrimp, but they do share the same environment on the Salisbury Plain Training Areas, and while Chirocephalus diaphanous may not think about the tanks and other military vehicles very often, the military planners are very considerate when it comes to the fairy shrimp.The fairy shrimp is a very lucky creature. It is protected under Schedule 5 of the Wildlife and Countryside Act 1981, and as luck would have it, rather than its habitat being destroyed by the military activity on the ranges, it has been found that the heavy tracks of the tanks, and the tyre-treads of other military vehicles, are actually helping to increase the spread of the shrimps across the plain. In fact, they have taken on the role performed for centuries by sheep and cattle who moved the eggs around on their hooves. This tiny creature, usually less than half an inch long, thrives in the muddy pools which form in the deeply rutted tracks across the plain. It lays its eggs in the mud at the bottom of these pools, and when the pools dry out, the eggs lie dormant at least until the next rainfall, although eggs have been known to survive for up to 15 years.

But the damage which tank tracks do has to be repaired, and that may mean filling in the muddy pools in which the shrimps thrive. So, when restoration of a track is considered essential, a lot of planning has to go into it. And so it was that I found myself high on the plain with Warrant Officer Les French, one of the Training Area Marshals, and Julie Swain from the DTE's Natural Environment Team. Before Les could organise the engineers to come in and restore the track, Julie had to be persuaded that there was no alternative, and before any work on the track was undertaken, that the impact on the fairy shrimps' habitat had been assessed, and if necessary moved safely out of the way.That is an example of what has struck me most powerfully throughout my months working with the various teams within the training areas - the way they work together to resolve issues, wherever possible, to everyone's satisfaction. There is a great deal of creative thinking behind their approach to problem-solving in particular, and the issues of environmental protection and management in general.

While everyone is clearly focused on their primary responsibility - facilitating essential military training - their understanding of, and regard for, the environment within which they operate is commendable. As Stephen Davis of Natural England (who was involved with the pioneering Salisbury Plain LIFE project between 2000 and 2005) told me, there is a confident working relationship between the various interested agencies. "Because of its importance to wildlife and natural diversity, over half of the training area has statutory designation. Natural England understands the MOD's priorities, and Defence Estates fully understands the conservation issues."

The huge area of Salisbury Plain contained within the training area is a unique environment in so many respects, thanks to the fact that for more than a century it has, effectively, been 'off limits' to most of the activities which radically alter a landscape. The area has not been ploughed or developed. That means that it has become, effectively, a protected habitat for a whole range of creatures, some of them welcome, some of them less so. While the damage done by rabbits and badgers causes perennial problems, and the lack of intensive farming activities has enabled gorse and scrub to thrive, the landscape has generally changed little since Victorian times. Rare plants and grasses thrive and provide the necessary shelter and nurture for a rich variety of wildlife.

The challenge facing Julie Swain and her colleagues is to maintain that rich diversity, while ensuring that the army can still prepare its troops for the challenges it faces today, and will face in the future. "A key thing for us as Natural Environment Advisors," said Julie, "is to maintain some bare areas for shrimps and some invertebrates (bees, etc), and some rare plants which like this sort of habitat." A marked example of this brings us back to the challenge of repairing damage done by military vehicles. Ruts have to be filled for failing to do so only exacerbates and extends the damage. If a track becomes too deeply rutted, it is only to be expected that the drivers of vehicles will avoid it, running alongside the damage rather than risking becoming bogged down in it. So, a track originally two vehicles wide would quickly become three vehicles wide, then four. But how do you repair that damage in a positive way?

That leads us nicely to the stone curlew, Burhinus oedicnemus, a rare and protected bird which thrives on the plain where over one third of the total UK population - at least one hundred pairs - have made their home. By the time the next issue of this magazine is published, the birds will have returned to Britain to nest and breed.

The stone curlew is not like most other birds. Not for it a nest in a tree away from prying eyes and predators. The stone curlew likes to be able to see clearly around 360. The bird nests on well-drained and sparsely covered ground in open landscape, scooping out a shallow recess in the chalk surface in which to lay its eggs. Predators include foxes, badgers and other animals, as well as crows and birds of prey, so they like a clear view. They are especially suspicious (and with some justification) of humans walking their dogs. Creating an improved nesting habitat for the stone curlew allowed the military, if I can be excused the awful pun, to kill two birds with one stone! Stripping the topsoil off an existing nesting site above Gore Cross during the winter, reducing vegetation and improving visibility, released the materials necessary to repair an extensive length of damaged tracks. And the whole project, like many others on the ranges, was undertaken by a unit of Royal Engineers, giving them vital practical training experience as well. A definite win/win/win situation: a bespoke nesting site for the curlews, essential landscape rehabilitation, and military training, all provided through a single collaborative operation. As the curlews are 'site loyal', returning to the same location year after year, their reaction to the new breeding site is being very closely monitored. As I mentioned in the first of this series, scrub clearance is an essential part of the landscape maintenance calendar. In the absence of heavy farming, gorse and other undergrowth would otherwise spread unabated, shading out and destroying the unique mix of grasses and plants beneath it. And if some of the plants were to disappear, then so too would the creatures which depend upon it.

Obviously scrub clearance is a risky business with all that uncharted and unexploded ordnance buried beneath the surface. Just looking at a pile of recent 'finds' underlines the dangers which exist, but programmed scrub clearance is an important part of an annual management cycle tailored to the need to maintain the integrity of 14,000 hectares of 'unimproved' chalk downland. The use of the word 'unimproved' may seem somewhat anomalous as the whole focus of the land management undertaking is to improve the natural habitat for so many creatures, but in ecological parlance 'unimproved' really means not loaded with fertilisers, and without it plants like the devil's-bit scabious could be overwhelmed. And if the downland goes, then so does the breeding habitat of the marsh fritillary, Euphydryas aurinia, a beautiful butterfly once common across Britain but now increasingly rare. Like the stone curlew, about a third of the entire UK population of this beautiful creature lives on Salisbury Plain.

The female fritillary lays her 300 or so eggs on the underside of devil's-bit scabious leaves, the leaves ultimately becoming food for the emerging caterpillars. The varied flora on the plain provides their ideal habitat, and regular grazing of the landscape by cattle or sheep - today it is largely cattle - is a crucial part of the maintenance of that flora. Regular readers will recall Daniel Defoe's observation nearly three centuries ago about the huge number of sheep grazing the plain. Their feeding patterns were the natural way of protecting and nurturing this unique environment. Continuing what the sheep achieved naturally is a huge and multi-faceted land-management project. And continuing military activity on the plain is a key, if surprising, part of that strategy.

Malcolm Twigg


A+ South & South West

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