Tackling Bracken at Loch Ardinning Wildlife Reserve
Article by David Shenton, Convenor, Loch Ardinning Wildlife Reserve Management Group
Over the 20 years since Loch Ardinning became a Scottish Wildlife Trust reserve, bracken has been gradually spreading further over many parts of the moorland (Muirhouse Muir).
This can actually help a few species, such as Stonechats and Whinchats, which like the cover, and Bluebells (provided that the bracken is not too dense ) but in general it has a deleterious effect on biodiversity where it encroaches into heather moorland and grassland. In particular, it inhibits growth of young trees.
Also, growing tall alongside paths, it can almost completely eliminate the view and be rather over-bearing, possibly even intimidating for some people. Strimming is carried out each year along the worst affected stretches of path.
Above: SWT Conservation Team, led by Carl Neumann, strimming along footpath, Muirhouse Muir, Loch Ardinning, June 2009
Two special areas of short grassland on Muirhouse Muir have been used by Black Grouse as 'lek' areas, where the males engage in a spectacular display, spreading out their white tail feathers and strutting about making crooning noises. This is designed to attract the females, which mainly stay out of sight beyond the edge of the lek. In recent years, only one or two males have been seen on the lek areas on Muirhouse Muir and lately bracken has been encroaching on this area too.
There are a number of possible ways to attack bracken:
- Manual – bashing with sticks, cutting with scythes, sickles or shears or pulling
- Powered – petrol-driven strimming or towing a bracken-bruising device
- Chemical – Asulam spray – not to be used where other fern species or some other reported sensitive plants grow (e.g. Birds-foot Trefoil).
Special efforts have been made in 2009 to tackle the bracken problem at Loch Ardinning in a more sustained manner.
In the Black Grouse lek areas, the bracken is not yet as dense as elsewhere. SWT volunteers and a SWT Conservation Team have been tackling it manually and clearing it to give grass a better chance to grow before the bracken starts again next year.
Above: Volunteers pulling, cutting and clearing bracken from Black Grouse lek area on Muirhouse Muir, July 2009
Another area more practicable for volunteers to tackle is a strip next to the nature trail where bracken has been encroaching on and obscuring blaeberry and heather.
Above: Volunteers pulling, cutting and clearing bracken by the Loch Ardinning nature trail, exposing blaeberry and heather, June 2009
These are the food plants of the caterpillars of the Green Hairstreak butterfly. Regular SWT volunteers have been joined in 2009 by volunteers from Butterfly Conservation and a good showing of blaeberry flowers and berries has been the result.
An area of dense bracken within the nature trail has been tackled twice in 2009 using a bracken bruising device towed behind a quad-bike.
Above: Sven Rasmussen, SWT’s Reserves Manager for West-central Scotland, driving a quad-bike towing a bracken-bruising device, August 2009
This creases the bracken stalks at approximately 6-inch intervals and has been shown elsewhere to be very effective at weakening the plants. An earlier bruising session, in 2007, resulted in weaker growth of bracken at the beginning of the 2008 season but unfortunately it did not prove possible to follow this up. In spring 2009, the growth of bracken in the previously bruised area was almost as great as ever. The double bruising in 2009 appears to be having a greater effect.
Above: Area within the Loch Ardinning nature trail after two bruising sessions during summer 2009 ; photographed in September 2009
Before the first sessions in spring, it is very important to ensure that no ground-nesting birds will be harmed. An adjacent area used by a pair of Tree Pipits near the nature trail was marked off using canes and the bruising activities kept well clear.
Cattle, because of their size, are beneficial in physically trampling bracken, unlike sheep. For a number of years a small herd of beef-cattle, mainly highland cows, has been grazing on Muirhouse Muir and fields immediately south of Loch Ardinning. The number of sheep has been reduced, to give a better chance for tree seedlings to grow on the muir.
Spraying of bracken has not been carried out at Loch Ardinning, but an area on the muir has been identified as a possible candidate for spraying in 2010.
To be effective in the long-term it will be necessary to continue all types of bracken-clearance over at least 3 to 4 years.
Tackling Bracken at Loch Ardinning Wildlife Reserve
Article by David Shenton, Convenor, Loch Ardinning Wildlife Reserve Management Group
Over the 20 years since Loch Ardinning became a Scottish Wildlife Trust reserve, bracken has been gradually spreading further over many parts of the moorland (Muirhouse Muir).
This can actually help a few species, such as Stonechats and Whinchats, which like the cover, and Bluebells (provided that the bracken is not too dense ) but in general it has a deleterious effect on biodiversity where it encroaches into heather moorland and grassland. In particular, it inhibits growth of young trees.
Also, growing tall alongside paths, it can almost completely eliminate the view and be rather over-bearing, possibly even intimidating for some people. Strimming is carried out each year along the worst affected stretches of path.
Above: SWT Conservation Team, led by Carl Neumann, strimming along footpath, Muirhouse Muir, Loch Ardinning, June 2009
Two special areas of short grassland on Muirhouse Muir have been used by Black Grouse as 'lek' areas, where the males engage in a spectacular display, spreading out their white tail feathers and strutting about making crooning noises. This is designed to attract the females, which mainly stay out of sight beyond the edge of the lek. In recent years, only one or two males have been seen on the lek areas on Muirhouse Muir and lately bracken has been encroaching on this area too.
There are a number of possible ways to attack bracken:
- Manual – bashing with sticks, cutting with scythes, sickles or shears or pulling
- Powered – petrol-driven strimming or towing a bracken-bruising device
- Chemical – Asulam spray – not to be used where other fern species or some other reported sensitive plants grow (e.g. Birds-foot Trefoil).
Special efforts have been made in 2009 to tackle the bracken problem at Loch Ardinning in a more sustained manner.
In the Black Grouse lek areas, the bracken is not yet as dense as elsewhere. SWT volunteers and a SWT Conservation Team have been tackling it manually and clearing it to give grass a better chance to grow before the bracken starts again next year.
Above: Volunteers pulling, cutting and clearing bracken from Black Grouse lek area on Muirhouse Muir, July 2009
Another area more practicable for volunteers to tackle is a strip next to the nature trail where bracken has been encroaching on and obscuring blaeberry and heather.
Above: Volunteers pulling, cutting and clearing bracken by the Loch Ardinning nature trail, exposing blaeberry and heather, June 2009
These are the food plants of the caterpillars of the Green Hairstreak butterfly. Regular SWT volunteers have been joined in 2009 by volunteers from Butterfly Conservation and a good showing of blaeberry flowers and berries has been the result.
An area of dense bracken within the nature trail has been tackled twice in 2009 using a bracken bruising device towed behind a quad-bike.
Above: Sven Rasmussen, SWT’s Reserves Manager for West-central Scotland, driving a quad-bike towing a bracken-bruising device, August 2009
This creases the bracken stalks at approximately 6-inch intervals and has been shown elsewhere to be very effective at weakening the plants. An earlier bruising session, in 2007, resulted in weaker growth of bracken at the beginning of the 2008 season but unfortunately it did not prove possible to follow this up. In spring 2009, the growth of bracken in the previously bruised area was almost as great as ever. The double bruising in 2009 appears to be having a greater effect.
Above: Area within the Loch Ardinning nature trail after two bruising sessions during summer 2009 ; photographed in September 2009
Before the first sessions in spring, it is very important to ensure that no ground-nesting birds will be harmed. An adjacent area used by a pair of Tree Pipits near the nature trail was marked off using canes and the bruising activities kept well clear.
Cattle, because of their size, are beneficial in physically trampling bracken, unlike sheep. For a number of years a small herd of beef-cattle, mainly highland cows, has been grazing on Muirhouse Muir and fields immediately south of Loch Ardinning. The number of sheep has been reduced, to give a better chance for tree seedlings to grow on the muir.
Spraying of bracken has not been carried out at Loch Ardinning, but an area on the muir has been identified as a possible candidate for spraying in 2010.
To be effective in the long-term it will be necessary to continue all types of bracken-clearance over at least 3 to 4 years.