Basin Notes - December 2012

Reserve Maintenance

Visitors to the Montrose Basin are often astounded by the sheer number and variety of birds at this coastal reserve, particularly at this time of year. There are many factors that make this enclosed estuary a bird haven and much attention is regularly paid to the rich mudflats which offer a food source to so many waders.

There are, however, other habitats within the Local Nature Reserve (LNR) that support life on the basin and the extensive salt marsh area is one such habitat.

Almost half (49.9%) of Angus and Dundee's salt marsh habitat can be found on the Montrose Basin LNR. This all means that the salt marsh at Montrose Basin needs special management to ensure its condition is maintained.

An area known as Sa'ty Dyke, visible from the Scottish Wildlife Trust four star visitor centre, was a relatively recent addition to the LNR in 2004. Work was carried out to reinstate and open up wet salt pans which fill with brackish water. Traditionally, this area was used to evaporate salt water in the salt-making process and reinstating these 'pans' has provided shallow open water scrapes favoured by waders. This work was intended to enhance the area for species like Redshank, Oystercatcher, Knot and Dunlin amongst many others.

Keeping the Sa'ty Dyke area in this condition does require input. If left alone, the salt pans would become increasingly vegetated through natural succession and this ideal habitat would be lost. Scottish Wildlife Trust and Angus Council Rangers' time and effort goes towards keeping this area in favourable condition for the various species it supports with a lot of help from willing volunteers, but much of the work is done by creatures of the four-legged variety.

Conservation grazing is an ideal practice for the Sa'ty Dyke area and the cows and sheep that have grazed the salt pans since 2010 have helped keep down areas of club rush and poach up the ground around the edge of the salt pans themselves. This muddying up of the pool margins encourages waders. The grazing regime implemented here, enhances the salt marsh habitat and maintains high biodiversity by allowing many different flora species associated with the salt marsh environment to thrive. Keeping the sward low and varied in this way also suits wildfowl species such as wigeon, as the vegetation is more palatable and accessible. Having some areas where the vegetation is lower helps waders feel safe as visibility is improved for predator evasion, while having sections where the sward is higher offers sufficient cover sought by more elusive species such as Water rail which is known to breed in the area.

Finding the right stock density for the grazing livestock can be tricky for such a site, as a fine balance needs to be struck. If the Sa'ty Dyke area is under-grazed, there is danger that it will become over vegetated and the areas of open water may become overgrown while over-grazing may result in the species richness of the sward being compromised. Selecting the type of livestock most suitable to the habitat also needs consideration. Sheep have previously been favoured on the reserve, but cows may be used in future to enhance the area for waders as they are known to poach up areas and assist in muddying up the edges of the pools. The approach that has been adopted is to graze the area at a low stock density, as this does not have a detrimental effect on breeding birds that may be using the site in the spring and summer months and any further vegetation management is carried out by reserve staff and volunteers.

The recent cold weather has offered an ideal opportunity to maintain the salt pans at Sa'ty Dyke. The challenge is often making sure the ground is firm enough to cope with the machinery needed to cut the vegetation. At the beginning of December, the grazing livestock were removed from the site for the winter months as there is not enough nutrition available for them during this time of low growth. Grazing animals will return in the spring as the seasonal change encourages more growth to be managed.

Monitoring the species present in the Sa'ty Dyke area provides the evidence needed to suggest whether the area is being managed effectively or whether changes need to be considered in the grazing regime and other practical management. Recent sightings of Teal, Wigeon, Kingfisher, Snipe and Water Rail confirm that the management has been successful for these species but it may be worth considering altering the grazing regime in future to enhance the habitat for waders.

The salt pan management on Sa'ty Dyke is just one area of the Montrose Basin managed for the optimum benefit of wildlife, so why not visit the Scottish Wildlife Trust Montrose Basin Visitor Centre to see the effect the management has had on the site and see the huge variety of wintering birds at this special reserve?