Twyford Down Project
Downland Restoration Areas
The timing of the main construction contract dictated when the areas destined for downland restoration would become available. Therefore it was necessary to divide the restoration work into three phases:
Both hand cutting and macroturfing methods were used to remove turf to the site,
with the most species-
Some 200 Juniper plants were also planted in five rabbit-
The topsoil was stripped and removed as in the previous site. No turf was available,
so the entire area was sown with a single mixture of seed. The bulk of this mix,
59 species in all, was seed of commercial origin, mixed with hand-
The road was broken up and the old, overgrown cutting faces and backs were cleared
of scrub. Chalk from the excavation of the northbound carriageway of the new cutting
was used to fill and landscape the site. Care was taken to give a natural effect
and recreate as closely as possible the original shape of the hill. The landscaping
of the site was carried out from the bottom upward in order to preserve areas of
potentially useful turf which lay at the top of one of the old cuttings. Topsoil
was spread over the chalk, thinly in areas which were to become downland, but much
more thickly where shrubs and trees were to be planted. All shrub and tree planting
was protected by stock-
All the downland restoration areas were surrounded by rabbit-
Nearly all herb-
Of the downland created following the construction of the M3, only the steep embankments of the new motorway are unlikely to need frequent management if they are to develop a wildlife interest. All the other grasslands will require annual management. To begin with, the restoration areas are considered individually while they are in a very early stage of development and require special treatment. However, as soon as is practical, the management of the reconstructed downlands will become an integral part of the management regime of the St Catherine's Hill SSSI.
Grazing is the traditional form of management on most chalk grassland and is the preferred method for St Catherine's Hill. Grazed swards usually support a greater diversity and abundance of invertebrates than mown hay meadows, and a different, though not necessarily richer, flora.
Mowing, however, is sometimes the only practical way of managing small isolated sites, or those where livestock are unsuitable, and it is far better to mow grasslands than to abandon them. On chalk, an annual cut in late summer is usually adequate to maintain the flora in the short term, but it is important that the cuttings are removed. In the longer term, rotational mowing will produce a more diverse grassland, supporting a wider range of invertebrates. Mowing is also the most satisfactory way of managing new grassland created from seed, for the first year or two after it is sown, as grazing by heavy livestock can damage the seedbed.
It has been a major criticism of most previous attempts at habitat translocation
and restoration that there has been little or no follow up, to ascertain the "success"
of the work. This means that little has been learnt about the processes involved
or what can be done to improve methods for use in the future. However, at Twyford
Down the Highways Agency is funding botanical and invertebrate monitoring for a period
of ten years. The progress of all the reconstructed downland areas and the translocated
flood meadows is being monitored both to assess the success of the work and to give
feedback to "fine-