British Moorlands

Narrow strip matrix

Strips run in all directions giving shelter whatever the wind directionThis is a modern version of the “small patch” system seen on some of the high class grouse moors.

Grouse like the edge habitat between young and mature heather and scientists have found that the density of breeding pairs is higher where there is more edge.

Ideally the old heather is cut or burnt to give a width of 1.2-2 metres and length about 20 metres. The traditional burnt patches of about 20 x 100 metres can result in two major problems.

Firstly, away from the edges, they offer an open, draughty environment. At higher altitudes and in most of Scotland this is not conducive to survival of young chicks in the sort of summers we get most years.

Secondly, chicks are easily seen by raptors if they are away from the edges and are too far from the long heather to get to safety in time. Click on the pictures to enlarge.

Cutting narrow strips is a very efficient way of increasing the amount of edge: a typical cutting speed of about 2 miles per hour can produce 15 miles per day and 30 miles of edge.  To get the same amount of edge from burning would need 200 fires of 20 yds x 100 yds.

These are the main findings where narrow strips run in different directions with intersections:

  • Narrow strip matrix

    NSM installed above a deer fence. Young native forest regeneration below fence

    Grouse use them immediately, spreading the birds into ground previously unused due to excess length & density of vegetation.  An even distribution of birds reduces the risk of localised high densities which can lead to parasite and disease problems.

  • By moving round the corners, birds can always find shelter from strong winds.
  • This reduces the chill factor and brooding time thus allowing more time for chicks to forage for food.
  • The improved micro climate appears beneficial to reproduction of invertebrates which are  a vital food source for chicks. Heather regrowth is also faster in the shelter of the cuts.
  • Strips in long straight runs are ugly and show up badly going up and down hill. They also facilitate low level fast raptor attacks. The solution is to aim for an S shape pattern, if cutting, and to stop the fire or lift the cutter every 25 metres to create a short ‘hedge’ which will force the hawk up a little so its approach is seen by the parent grouse. The birds are so near to thick cover and into it so fast that losses to raptors are negligible, the main loss being displaying males taken in flight in Spring and these are soon replaced by surplus non-territorial males. Such defence against raptors will be needed even more in the future as raptor populations are likely to increase with sophisticated surveillance systems leading to prison sentences for those who are tempted to persecute them.
  • A hedge jump makes a good fox snaring site where a 250mm wide “run” is cut through it with a strimmer.
  • Tick infestation on chicks seems to be very much reduced,  probably because  chicks don’t have to go through tick hotspots such as dense vegetation or tracks made by deer or sheep. Also, research has shown that tick biting is less on healthy well fed chicks which move faster and preen themselves better than chicks which have been chilled or weakened by hunger.
  • There has been criticism of these matrices on the grounds that grazing animals concentrate on the young heather within the strips and overgraze it. This should not happen if enough cutting or burning is done each year, e.g. 100 acres per 1,000 acres each year if on a 10 year cycle.

Blanket bog habitat enrichment Great care must be taken to avoid exposing too much bare peat which can be oxidised or set up an erosion problem. A small divot plough is used to cast divots which leaves a wet trench and drier divot. Heather then colonises the divot with young nutritious growth and mosses, bryophytes and grasses grow in the shelter of the trough which also provides some drinking pools.

Overhanging divots give chicks shelter from wind and rain and also refuge from aerial predators. This technique is fine for bleak open areas but where there is heather to be burned the divots should be smaller and more scattered as they dry out quickly and become difficult to extinguish when ignited during muirburn.  A water jet type fogging unit is needed in such cases.   Next section: The Cutting Alternative

British Moorlands