Flora Locale - Restoration Methods



Twyford Down Project

Restoration Methods

The aim of the restoration was to create new areas of herb-rich downland with a characteristic, rich invertebrate fauna on the restored A33 and around the Arethusa Clump on Twyford Down. It was intended that, within a relatively short time, these areas would become integrated into the St Catherine's Hill reserve of the Hampshire Wildlife Trust.

The process of habitat restoration can be divided into three distinct phases:

   The first phase is the preparation of the site. This can involve denutrification by various methods, adjustment of soil depths, and in some cases landscaping to alter aspect.

    The second phase is the introduction of the relevant plants in suitable proportions. This can be accomplished by variations of turf translocation, seedling and planting of pre-grown plants. The invertebrate fauna would not have to be introduced on Twyford Down as all the restoration sites were adjacent to established chalk grassland.

    The third phase is the manipulation of management techniques to drive the development of the plant and animal communities towards the desired grassland types. The most commonly used methods on chalk grassland are mowing or grazing, with grazing generally considered to give the most desirable grassland.

This programme of downland restoration involved the use of three main methods: turf translocation, seeding and plug plants. Approximately 0.5 ha could be turfed and the remaining area would receive seed and plug plants which would, where possible, be of local provenance.

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Turf Translocation

Two turf translocation methods were used. Before the main works began, a small area of herb-rich turf was identified above the Hockley Junction which was rich in Horseshoe Vetch, the food plant of the Chalkhill Blue. As this was of value to the restoration, all 500 square metres were translocated into the first restoration area using traditional hand methods.The main translocation of turf employed large-scale turfing equipment, using a technique known as "macroturfing", moving large, thick turvse. This method has many advantages over traditional turfing, virtually eliminating problems of frost and drought damage, and because the turves are thick most burrowing invertebrates and deep-rooted plants survive.

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Seeding and Plug Plants

The 260 kg of seed needed for the 6.5 ha to be sown could not be collected locally without causing unacceptable damage to both flora and fauna of the local source sites, most of which were SSSIs. Therefore the majority of seed mixes comprised commercial seed of known origin, virtually all species coming from south of England sources, and many from areas close to Hampshire. Where species were unavailable commercially of were in very short supply, seed was collected by hand from local downland and incorporated into the mixes.

The seeding was supplemented by 100 000 plug plants of eight species which were important butterfly food plants or were unlikely to grow well from seed. These were grown from seed or cuttings which were collected locally, many from St Catherine's Hill.

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Progress to Date Restoration Areas Seeding and Plug Plants Turf Translocation Introduction