Breckland conservation project
Their long brown ears slowly turned, but their eyes remained transfixed by my presence. Wherever I walked, a triangular formation of stock-still rabbits surveyed my intentions, while others played blissfully in the midday sun. From a safe distance they were examining me as closely as I was them. I was visiting the Brecklands, a land steeped in rabbit history, that covers some 370 square miles of inland Norfolk and Suffolk and is historic home to the warreners. These warreners had been the guardians of the vast tracts of land; their rabbits, for fur and meat, were enclosed by pillar mounds offering protection from poachers whether human or animal. On my visit, I passed a few signs bearing the name coney and warren, a historical reminder of the relationship between man, land and rabbit.
The Brecks are perfect rabbit terrain. The Mediterranean-style climate, with less rainfall and hotter summers, combined with the sandy soil are ideally suited to their needs. They have plenty to eat and are surrounded by protective established networks of warrens built up over centuries. As I stood looking at an aerial photograph from early in the last century, bar the odd tree and fewer warrens, the field I stood on was virtually the same.
A rabbit conservation area
World War I and the rise in farming technology and practices changed the Breckland?s habitat. Forests around Thetford were planted to avoid a national shortage of wood. The rabbits became such an irritant in the new plantations that the Forestry Commission employed 30 warreners to control them. In 1947, 80,000 were trapped in one month on 6,000 acres. In the decades since then, the landscape has changed further. In the 1950s, the grasses and foliage grew unchallenged, giving way to pine and birch scrub, all after-effects of the myxomatosis outbreak that curtailed the national rabbit population.
For once, the reason for my visit was not one of control, but to observe rabbit conservation. I went to see the good work carried out by the Norfolk Wildlife Trust (NWT) in nurturing and protecting the Brecklands as well as to learn about the behaviour of their wild rabbits. This being the oldest wildlife trust in the country, it has also pioneered research into rabbit conservation. NWT Breckland field officer Darrell Stevens outlined the role that rabbits play in the conservation of the Trust?s heaths which provide a vital habitat for rare wildlife. They were the first nature reserves in the UK to fence in rabbits and use them as a primary management tool. The recent Breckland Biodiversity Audit, led by scientists from the University of East Anglia, showed that 12,500 species of plant and animal live in the Brecklands, which includes 28 per cent of the different types of the UK?s rare species. And all in an area covering less than one per cent of the UK?s land surface.
The right kind of overgrazing
Conservation is important in keeping the delicate balance of the ecosystems that exist in different areas of our country. The Breckland Biodiversity Audit found that the best heathland was one disturbed by rabbits. As I walked through it, it was like walking on a soft green carpet. ?Good, healthy Breckland should be crunchy and spongy when walked upon, a sure sign that plenty of lichen and mosses are present,? Darrell told me. ?You only get lichen-rich heaths in sandy soil with extensive grazing, but it has to be the right sort of grazing.? Surprisingly, the weight of a flock of sheep in the numbers required to keep the ground bare would be counterproductive, destroying the lichen the trust is trying to promote. Fortunately, rabbits graze tight to the ground and are light on their feet.
Darrell continued, ?We want overgrazing. The more disturbed bare ground, the better for the whole ecosystem. You only get the key species and their communities in grass heathland when you have a high density of rabbits.? On the 40 acres on which we stood, Darrell estimates that it holds between 2,000 and 2,500 rabbits. Using a telescope, Darrell is reliably able to estimate the number of rabbits on the land. When spotting rabbits on farmland, the old adage is that you only see a third of the population at any one time. Darrell?s data suggests that this is about right. The stone-curlew, together with rare plants such as the spike speedwell, are just some of the beneficiaries of this scheme. Data collected from these counts is essential in ensuring the right management plan is offered. If for some reason it isn?t working, then the data stored by the trust can be used to discover why and changes can be implemented. For example, grass swards are measured and compared against the rabbit populations and the resulting data is analysed to suggest the possible relationship between the actions of one animal affecting the survival of others.
To manage these schemes successfully, the rabbits have to be enclosed. This not only concentrates their grazing in the right areas, it also protects the adjacent land from being damaged. The enormity of the enclosures gives the rabbits everything they need. I was eyeing up large, healthy rabbits, not ones that have become frail due to too much competition for food. This is because Darrell knows his rabbits. Only when you have a deep understanding of their habitat and hierarchy can you manipulate rabbits into starting new colonies or relocating to new areas in order to encourage new heathland.
Establishing new warrens
The land and its management plan have to be right in order to support these colonies. It is one thing getting rabbits to move further away from their home, but it is another to persuade them to settle down and survive. Extreme care has to be taken when moving rabbits and what initially surprised Darrell was the manner in which rabbits interacted with each other. It was not as straight-forward as catching up rabbits and putting them back together somewhere else. They live in a brutal society. The hierarchy of the warren has to be right, otherwise violent outbreaks occur, occasionally with deadly consequences.
I cast my eye over the vast warrens, but only saw a few holes for their size. Over three centuries, countless tons of sand have been moved and often, being more than 100 yards in length, these are deep, complex and expansive warrens. The ground disturbance from rabbits is hard to replicate artificially. Darrell starts the whole process off with selective areas being tilled to produce bare earth or by ploughing a shallow furrow, which encourages the rabbits into fresh digging.
What surprised me was how Darrell shifts a territory into a neutral zone to start a new colony. As we looked at an enormous scenting pile of rabbit droppings, Darrell described the importance of such places. These matriarchal mounds give the dominant doe a platform to survey and mark her territory; others then follow and leave their scents. These scents which are full of important chemicals that react together, signalling what?s what and whose warren it is, making a definitive scent-marking area. The droppings were encircled by mosses and lichens. Initially, rabbits eat their droppings, a process known as refraction. The second deposit of droppings, which are PH neutral, act as a natural fertiliser. However, the rabbits? urine is highly acidic. The lichens, being acid tolerant, are able to thrive, whereas straight grasses and crops, which are not, become tainted and die. These matriarchal scenting mounds are dug up and gradually moved to new areas, thus encouraging the population to move further afi eld to mark and expand their territory. This preserves the rabbits? social hierarchy, which is fiercely protective of its own warrens.
Stoats, along with foxes, are the main predators, but even a mustelid gladiator such as the stoat has been seen by Darrell to be chased off by a protective rabbit. With an integral security system constructed in a huge expanse of pipes such as these rabbits have, predation isn?t the main threat. The most significant danger to this rabbit population is natural biological warfare.
Myxomatosis is a curse, and sand and stone are no protection against it. Fortunately for Darrell, these rabbits appear resilient to this disease, perhaps having built up a resistance to it over generations. When it hits these areas it affects all of the rabbits, but where an estimated 90 per cent of the juvenile stock die, the survivors grow stronger and breed immunity. When the disease appears more prevalent, it is likely to be down to the eruption in the vectors of myxomatosis rather than a more deadly strain. These vectors, the flea, mosquito and tick we take for granted, but Darrell alsotold me about the harvest mite as a major vector of myxomatosis, which explains why so many areas are only affected after the harvest.
Understanding the rabbit
As we made our way back, we left the rabbits happily munching on some lichen and fungus on a landscape that has been fashioned by their chisel-like teeth. My experience with the NWT suggests that the rabbits? presence is vital for the survival of their immediate ecosystem. What did I learn from my day out in the company of Darrell and his rabbits? Conservation plays a bigger role than many realise and conservationists have much knowledge to offer those willing to learn about how our land and its ecosystems function. Darrell wants to keep his rabbits in, I want to keep mine out. The secret to both sides of the rabbit-proof fence is the knowledge of the rabbit. It is just as important for me to understand the behaviour of the rabbit for control purposes as it is for the Norfolk Wildlife Trust and other conservationists.