Nearest town or settlement: Aldeburgh
Contact detailsOrganisation: Royal Society for the Protection of Birds (RSPB)
Website: Minsmere reserve on RSPB website
The arable reversion fields at Minsmere cover over 260 hectares, of which the majority are being reverted to acid-type grassland and a smaller area to heathland.
A news item about the project can be found here but an update and full review was published in 2010. This can be obtained from the RSPB. Details are Heathland Creation on Arable Land at Minsmere: A summary of the research and results 1990-1998 and the costs involved. This provides an overview of a number of separately published research papers and outlines future plans for the site. It can bought from NHBS.
Enact 4 (2) p.10-11 Summer 1996 © English Nature 1996
The Suffolk Sandlings and the East Anglian Breck are the scene of some impressive large-scale heathland re-creation projects. Geoff Welch and Malcolm Wright bring us up to date with the progress of these schemes.
The RSPB has placed a high priority on conserving threatened lowland heathland in Britain, through active management of existing heathlands. In 1990 the Society extended its Minsmere reserve by purchasing 158 ha of adjacent arable land, with the aim of restoring it to heathland. This land had once been part of the extensive Suffolk Sandlings until it was brought into cultivation in the late 1930s. The total extent of heathland and potential acid grassland habitat on the reserve is now 265 ha. The existing heathland supports important populations of nightjars. It is hoped that the work will encourage stone-curlews and the existing population of woodlarks to breed on the newly reclaimed heathland and acid grassland.
The main problem in restoring ex-arable land to heathland lies in the soil. Years of arable cultivation result in nutrient levels which are far in excess of those found in typical heathland soils. Unless attempts are made to reduce these residual nutrient levels, there is a tendency for recolonising vegetation to be dominated by species such as nettles, or arable weeds. Alternatively there may be a rapid succession through heathland to bracken- or scrub-dominated communities.
Between 1990 and 1995 the newly-purchased ex-arable land was cropped to reduce nutrient levels. Crops included winter and spring barley, and linseed. Since soil nitrogen levels were low, it was possible to add inorganic nitrogen fertiliser to improve crop yields. This was important because it increased the uptake of other nutrient elements such as phosphorus and calcium. All the straw was removed at harvest.
Soil chemistry changes have been monitored throughout. At the start of the monitoring the soil pH ranged from 6.0-7.2, compared with typical values of 3.8-4.2 for heathland acidic soils. These high pH values were almost certainly the result of applications of lime and marl over many years. The soils in the ex-arable area also showed high levels of extractable phosphorus, probably attributable to residues of phosphate fertiliser applications.
After five years of cropping, extractable phosphorus levels had fallen very close to the expected levels in heathland soils, but there was little evidence of a decline in soil pH and exchangeable calcium. Deep ploughing was also considered, but soil analysis showed that there was little variation in nutrients or pH to 60 cm, indicating that deep ploughing was not an option at this site.
Further experiments in soil acidification techniques have been carried out since 1993 through the work of an RSPB-funded PhD student. Differing amounts of bracken mulch, fresh pine chippings and elemental sulphur have been incorporated and their effects on soil pH monitored. Results to date have shown that the pine had virtually no effect, bracken brought the pH down in each case (the more bracken mulch applied, the greater the drop in p14) whilst sulphur had the greatest effect. Used on its own, a 10 cm thick application of bracken mulch reduced soil pH from 6.7 to 4.7 over a 29 month period, and this reduction appears to be persisting. A similar but more rapidly-achieved drop was achieved applying sulphur at 1-2 tonnes per hectare.
Because of the scale of the work we wish to undertake at Minsmere, there are practical difficulties in (a) finding enough bracken mulch or (b) affording enough sulphur! We have experimented with a combined application of 1 tonne/ha sulphur and 4 cm of bracken mulch, and the results of this application look very promising; pH has been reduced to about 4.5, which is very close to the levels found in acid heathland soils.
As this article goes to press, we are scaling up the experimental work to full-scale field application over a plot of 21.5 ha, using both sulphur and the sulphur and bracken mixture. After a year to allow the pH to fall, it is intended to sow a native acid grassland mix on part of the area, and to add heather foragings to another part of the plot. Natural regeneration, combined with topping, will also be tested to see what natural vegetation develops. The long-term aim is to create a mosaic of heather and acid grassland, with scattered gorse and trees, managed traditionally by grazing with sheep and rabbits.
In 1978 Roper's Heath was purchased by the Nature Conservancy Council and a decision was made to attempt heathland re-creation on this 12 ha arable area. In the spring of 1979, a crop of barley was sown with no input of nutrients, and this was successfully harvested in the autumn. This was followed in 1980 and 1981 by two crops of rye in order to further reduce the residual nutrients in the soil. Rye is a particularly good crop to grow to reduce nutrient levels. All three of these crops were sown by a neighbouring farmer, who grazes sheep on part of the NNR, and all three were financially viable, with no subsidies being paid by NCC.
After this final crop of rye was harvested in the autumn of 1981, natural vegetation was allowed to colonise the area. This was cut with a tractor-mounted topper in late summer 1982, after which sheep grazing was introduced. Roper's Heath has been regularly sheep grazed since, with the occasional cut to control patches of ragwort, thistles or nettles when needed. Heather seedlings were first noted growing in 1985.
The vegetation has continued to improve year by year until it is now recognisable Breck grassland (National Vegetation Classification U1), dominated by sheep's fescue, common bentgrass and sheep's sorrel. In spring the grassland can appear misty blue with the tiny flowers of field forget-me-not, to be succeeded in turn by the pink of common stork's bill and the yellow of mouse-ear hawkweed. The variety is further enhanced by patches of lichen heath which have now developed.
From 1990 onwards considerable numbers of rabbits moved onto Roper's Heath from adjacent heathland and there is now a large warren. Their diggings and scrapings have created bare earth, ideal for the rich invertebrate fauna which is found on the site. The rabbits have also assisted in creating the right conditions for stone-curlews, which require short, well-grazed turf with some bare ground and stones and flints on the surface. Stone-curlews have nested twice in recent years and frequently use Roper's Heath for feeding and roosting. Woodlarks returned to nest on the reserve in 1994 and are often to be found feeding on the short turf; which is also much used by commoner species such as lapwings, stock doves, redwings, fieldfares, pipits and wagtails.
There is no doubt that the heather re-creation on Roper's Heath has been a success. It is also often used as a demonstration site to promote the possibilities of re-creating Breck grassland heath elsewhere.
Geoff Welch was the RSPB's manager for their Minsmere reserve.
Malcolm Wright was English Nature's site manager for the Breckland Heath National Nature Reserves.