The hills are alive with talk of heather beetle
In what seems to have been one of the worst summers for this moorland pest in almost ten years, huge areas of heather across Scotland and England have been damaged during the course of June and July. We all know the time, care and cost which go into managing moorland habitats for grouse, so it’s hard to see a year’s work threatened by such a difficult and enigmatic problem. Many moors are postponing or reorganising their shooting in response to beetle damage, which turns healthy, flowering vistas of purple undergrowth into a drab, tangled mess of dead and dying vegetation.
Heather beetles are a naturally occurring species which is found across Europe. They’ve always been present in our moorlands, and heather has naturally evolved to handle a certain amount of damage caused by these little golden-coloured beetles. The problem arises when heather beetle numbers explode into extraordinary blooms of prosperity – in bad years, even a square metre of heather can yield more than a thousand of these hungry little creatures. The adult beetles disperse in March to lay their eggs in suitable habitats, sometimes drifting for several miles away from their point of origin. They lay their eggs and die, and it’s when these eggs hatch that the problem begins. Beetle larvae emerge in June to eat stems and shoots of young heather, and the damage becomes really noticeable in July when plants suddenly turn a foxy red colour. Just as heather should be blooming into its full glory, it’s suddenly pulled up short. Grouse quickly move away from affected areas, and even the most promising season can be overturned by a bad outbreak of beetle.
We don’t understand why heather beetles explode into their millions, but there is some evidence that it’s associated with changing weather patterns and milder winters. The first massive outbreaks of heather beetle were observed in the Netherlands during the 1970s and 80s, and the phenomenon seems to be moving slowly northward into the UK. On smaller English moors, an outbreak across five hundred or a thousand acres of moorland can be disastrous. Scottish moors are often larger and can accommodate this level of damage, but there are many examples of outbreaks which ran across ten or fifteen thousand acres, particularly in the North Highlands.
Under normal circumstances, many heather plants can survive a major outbreak and they will often put out shoots of recovery and regrowth into the autumn. By the following spring, even the worst-affected areas can seem to have recovered much of their strength, although this is heavily dependent upon livestock grazing levels and management work. In more serious situations, beetle outbreaks recur for three or four consecutive years – and no sooner has the damaged heather recovered than it is simply damaged again. In these situations, there is a serious risk of heather coverage being lost altogether.
We can’t do much to prevent heather beetle damage. There’s no effective way to kill the beetles without harming other moorland insects which are crucial for grouse production. Studies have explored the most effective ways to restore and improve heather once it has been damaged, and there is some evidence that well managed moors are less likely to experience disruption over the long run. In most circumstances, the best advice is not to panic – and to carry on breaking up good heather with damaged areas as part of a normal rotation. It hasn’t been a stellar year for grouse in many parts of the country, and this can feel like the latest issue in a pattern of many - we have to hope that this bad year for beetle will be followed by a chance to recover and recuperate.