Friday, 27 March 2015

Peak District Heather Beetle Restoration Trial

The best treatment for heather following damage by heather beetle has long been a topic that has produced much debate, and this trial hopes to provide land managers with the best, up to date information to enable them to respond to outbreaks of beetle in the most effective way.

During the winter of 2012, the Heather Trust set up a scientific study on two estates, Combs Moss and Crag Estate, in the Derbyshire Peak District to explore the effects of different management techniques on heather, which had been damaged by major heather beetle outbreaks in the summer of 2012. Penny Anderson Associates are carrying out an ecological survey of the recovering heather following the beetle damage.

Three plots of damaged heather were marked out on different parts of each moor and the plots were cut, or burnt and the third plot was left without treatment to act as a control.

At Combs Moss, concerns were raised in the project’s planning stages that the heather seed bank was being exhausted by attempts to replace heather killed by the beetle attack during a continuous series of outbreaks of heather beetle. This might influence the ability of the heather to regenerate, and to quantify the problem, a separate piece of work has been carried out on Combs Moss to over-seed some areas of heather damaged by beetle with heather seed. Monitoring the regeneration of the heather and comparing this with the plots included in the main project will provide an indication of the level of depletion of natural heather seed as a result of a series of heather beetle outbreaks.

The most recent survey information has just been made available and this covers the changes to the vegetation up to July 2014. Although the project runs until 2018, the monitoring is starting to pick up some interesting differences between the two estates:

Crag Estate
  • Burning “beetled” heather in the spring after the damage occurred produced the highest percentage of regenerating heather cover; 
  • Burning produced more new heather seedlings than cutting; and
  • The control plot has shown almost a 50% loss of heather cover in the same period.
Combs Moss
  • The results are much less conclusive; 
  • The ground is much wetter and it appears to have been subject to a cycle of recurring beetle damage for several years prior to the start of the study; 
  • While some over-seeded plots have showed healthy burst regeneration of heather seedlings, others have made little progress.
It is too early to draw any definite conclusions from this work, but early indications suggest that the best way of restoring young, heather dominant vegetation is by burning the damaged heather after the beetle attack. Given that regeneration from cutting is traditionally somewhat slower, the next phase of monitoring will inform a more in-depth discussion on the relative merits of each treatment.

The results of this work will supplement the similar work that is taking place on Langholm that is due to complete in 2015.

I am grateful for the support for this work from the landowners in the Peak District and at Langholm. SNH provided some pump-priming funding at the start of the Langholm Project and I am hoping for some further support to help complete the work. Natural England provided support at the start of the work in the Peak District, but the rest of the funding has been provided by the Trust.

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