Case Study: Restoration of rank wetland habitats to benefit waders

Author: Dan Brown, Dr Duncan Allison & Sarah Bird
Farm: Anston Farm, Dunsyre, South Lanarkshire

Aims:

Anston is a 651 ha mixed upland livestock farm in South Lanarkshire. A variety of habitats can be found across the farm. The hill ground includes dry heath and acid grassland, whilst the upper in-bye fields contain a mixture of permanent pasture and grass/clover leys. The in-bye on the lower ground runs down to the South Medwin river and it is here, on the river floodplains, that marshy grassland dominates, with scattered remnants of lowland raised bog nearby.

Over numerous years the field had become wetter, as drains stopped being maintained. This, in combination with reduced grazing levels and no cutting, resulted in the dominance of marshy grassland vegetation (primarily soft rush) and grasses (e.g. tufted hair-grass). The vegetation had become too tall and dense to be used by waders, as confirmed by a 2013 RSPB breeding wader survey which surveyed the entire valley within which Anston sits. No waders were breeding on the wetland, but curlews, lapwings, redshanks, snipe and oystercatchers were all recorded on adjacent fields. The decision was made to try and improve the habitat, knowing that birds were nearby to take advantage of improvements.

Management:

The RSPB provided advice, including the importance of cutting and grazing in order to keep wetland vegetation sufficiently low in height, in order to attract breeding and feeding waders.

In September 2014, AMW Arboreal were contracted to carry out one day’s work with a Softrak, a low ground-pressure vehicle equipped with a forage harvester, chipper, reed cutting head and heather cutter. This allows management of rank rush, reed, heather and scrub whilst protecting wetland surfaces. It has an average speed of 1-2 mph and can cut between one-third and half a hectare per day.

Around 0.5 ha of dense rush pasture was cut and removed, with cuttings piled together to compost over the following year (a composting licence may be required for larger jobs). This work was undertaken as part of a management agreement between Dr Allison and the RSPB.

The following summer (2015), Dr Allison used a tractor-mounted flail mower to cut re-growth and access other uncut areas, using the open areas and ‘rides’ that had been cut into the dense rush by the Softrak. As a result of the benefits from this initial work, the decision was made to scale up the management for the remainder of the wetland, and a further 6 days of rush cutting with the Softrak were carried out in March 2016. This time, cuttings were left on site to mulch down, as Dr Allison felt there would be benefits for soil fertility (see below).

Dr Allison used a Kverneland FXJ flail topper, which was found to have benefits over the more conventional whale tail (hammer) head flail, or long swinging blade vertical axis type pasture topper. The FXJ is fitted with pairs of swinging "J" shaped flail blades with intermediate fan lifter fingers. The blades cut and shred the dense rush more efficiently than other machines, with near double the forward travel speed being achieved. The shredding action pulps the fibrous vegetation which was blown from the rear of the machine and left on the surface. The deposited shredded material composted down far quicker than when cut by the farms other topping machines, and quantity and variation of flora and fauna species regrowth was noticeably improved. Additionally, shredding and allowing the rush vegetation to compost on the surface returns potash to the soil, a distinct advantage over removing the cut vegetation. Carting away the vegetation ultimately reduces the fertility of what is already poor land.

Wetlands are problematic and in certain situations can potentially be dangerous. Dense cover can prevent ground visibility, and many farmers are concerned about getting equipment stuck as a result. Similarly, livestock safety becomes an issue where there are unknown or obscured ditches which may prevent grazing.

By removing the dense rush with the Softrak, Dr Allison had a much better understanding of ground conditions i.e. the location of ditches and waterlogged areas. This enabled him to access the site with the quad during drier weather, and gave him the confidence to put sheep out in greater numbers.

The wetland has been brought back into a condition that will allow further follow-up management during dry periods in the future.

Benefits and costs

One of the benefits to arise is increased grazing. During drier periods, sheep are now put out onto the site, allowing grazing of grasses and herbs previously hidden by the rush pasture. There is more grass than was expected; it has taken the removal of rushes to ‘open up’ the sward and make apparent.

A second benefit is access. The micro-topography of the site is now clear to see; standard machinery (quads, tractors) can now enter the site. Previously, the site was a no-go zone due to fear of getting stuck.

Continued rush management and grazing will also benefit the farm business in the longer-term; it will improve habitats for target species within agri-environment schemes, and demonstrates a willingness on part of Dr Allison to maximise his management for wildlife. In time, this should enhance his chances of entering future agri-environment schemes. Removing tall dense rush will increase evapotranspiration, allowing the wetland to dry out more quickly during the summer, in turn making site management requirements easier to undertake (i.e. machinery and livestock access).

In terms of costs, the Softrak work was funded by a local RSPB budget for conservation work in South Lanarkshire. This funding stream was earmarked for trialling novel management techniques that couldn’t be funded through existing agri-environment options. The contractors used cost £360 per day (plus haulage).

In addition, fluke is present in the area and it is acknowledged that grazing these areas may increase the chances of infection.

Tips for other farmers

Due to the high costs involved, a Softrak is likely to only be appropriate in certain circumstances. At Anston, the farm lies within a valley that supports important populations of lapwings, curlews, snipe, redshanks and oystercatchers. It would make sense that the two following criteria are met if considering using a Softrak elsewhere:

a) priority species are adjacent to the site so there is a high chance of utilising the improved habitat

b) it should only be used on farms that possess suitable equipment for follow-up management (topping, grazing) as well as a clear understanding and commitment on the part of the farmer or land manager to undertake the follow-up management.