Go nuts for dormice
Signs of recovery for threatened species as national dormouse conservation programme comes of age
Twenty one years of continuous monitoring, meticulously planned reintroduction programmes and the efforts of hundreds of volunteers seem to have paid off as People’s Trust for Endangered Species (PTES) reveals that the threatened hazel dormice is beginning to show early signs of recovery.
The National Dormouse Monitoring Programme, which is the longest running national mammal monitoring project in the world, is managed by PTES and co-funded by Natural England. This UK wide conservation initiative has been collecting data provided by volunteers on hazel dormice (Muscardinus avellanarius) numbers since 1988, to find out how well the animal is doing against reports of its chronic decline.
Announcing news of this long-awaited trend, PTES Chief Executive Jill Nelson says:
‘An analysis of data up to 2008 shows that although dormice are still a threatened species the decline appears to be slowing down markedly. It is clearly too early to be totally confident about the long term future of the species, but we have reason to be optimistic that conservation efforts are repaying dividends after more than two decades of dedicated effort.’
The National Dormouse Monitoring Programme data is used to construct an index with which to assess the conservation status of the population. Overall the index shows a decline in dormouse numbers of 39% between 1992 (the first year when there were sufficient records to begin the analysis) and 2008. However a closer look at the data reveals that whilst the decline between1992-2002 was 31%, between 2002-2008 it had slowed to 9%, indicating a less drastic decline over the last six years.
Over the last 21 years of the National Dormouse Monitoring Programme, most of the woodland survey sites have been subject to dormouse-friendly conservation management. ‘Whilst the slow down in the decline is very encouraging’, says Jim Jones who is leading another PTES initiative: the Hedgerows for Dormice campaign, which aims to identify dormouse hotspots and address disastrous fragmentation of habitats, ‘ the species is still in decline, so conservation and monitoring efforts remain a priority if dormice are not to disappear from the British countryside’.
During the 1990s research established that the loss and decline in quality of dormouse woodland and hedgerow habitat were the principle causes of population decline. Guidelines for appropriate habitat management were created and a reintroduction programme was established to return dormice to counties from where they had become extinct. The improvement in the dormice population trends could be an indication of the uptake and success of this conservation advice and the reintroductions, although further research efforts are necessary to establish this conjecture.
Dormice populations are very vulnerable to climatic changes, in particular wetter springs and summers, when foraging for food becomes harder and when warmer winter temperatures interrupt successful hibernation. Unlike other small mammals who are able to breed prolifically, dormice usually have only one litter a year, sometimes two, which means that a poor breeding year can have a heavy impact on a population. Therefore several continuous years of unsettled weather can be catastrophic. Hence why long term monitoring of dormouse numbers is so important, so that trends over many years can be revealed and conservation efforts targeted efficiently and to maximum effect.
The effects of weather are compounded by a lack of food and nesting sites in lower quality habitat, so the corollary is that improving management of woods and hedgerows for dormice can increase the availability of resources and protect populations from the detrimental effects of sustained periods of poor weather. In addition increasing connectivity between dormice habitat allows dormice to disperse to areas where the environment offers them a better chance of survival.
26.05.09
