Summary Report of a Natural England visit in July 2024

On 5 July 2024, a site visit was undertaken by two officers from Natural England to review the effects of the management that is being carried out on Wimbledon Common SSSI. The results from this visit will help to inform understanding of the site and provide evidence for future management priorities in order to achieve SSSI objectives.

This visit covered all aspects of the Commons’ natural landscape which helped to provide a good overview of current SSSI condition. The following habitat summaries were written by the aforementioned Natural England officers.

 

Grassland

The overall extent of species-rich grassland is being maintained. Evidence was found of the recent removal of silver birch along the margin of one of the grassland areas on the golf course which will slightly extend the area of open habitat.

Current management of species-rich grassland is appropriate to maintain high plant diversity, to promote the special character of the grassland , to maintain low nutrient levels, and to prevent the accumulation of thatch.

There is widespread evidence of high habitat quality in the presence of abundant tormentil (Potentilla erecta), sheep’s fescue (Festuca tenuifolia) and yellow rattle (Rhinanthus minor) and frequent occurrences of London rarities, including mat grass (Nardus stricta) and common sedge (Carex nigra), and additional interest in the presence of heather (Calluna vulgaris). Purple moor-grass (Molinia caerulea)  is also locally frequent, a very unusual feature in London’s grasslands.

Associated plants in the grassland include heath rush (Juncus squarrosus), green-ribbed sedge (Carex binervis), oval sedge (Carex leporine), heath bedstraw (Galium saxatile) and heath woodrush (Luzula multiflora).       

There are no indications of management problems, such as weedy patches, heavily trampled areas or disturbed areas.

The current management of ‘cut and collect’ ensures that the establishment of trees and scrub is effectively controlled over most of the area. The grassland is remarkably free of woody scrub such as bramble. There is a small patch on The Plain (approximately 0.17 hectares) where heather has become dominant (adding valuable habitat diversity) where young oak is frequent , which will need some attention before too long to prevent this losing its open character. (note: the area of young oak was subsequently cut back by volunteers and stump grinding took place during 2025 to remove the issue of future scrub encroachment on The Plain).

There is a small patch of tall grassland within The Plain which appears to be routinely left uncut. This area has abundant false oat grass (Arrhenatherum elatius), with other typical associates of taller swards such as tufted vetch (Vicia cracca) and hogweed (Heracleum sphondylium). This provides useful structural diversity and is likely to be of value to invertebrates seeking pollen and nectar. However, of concern is the presence of the invasive, non-native plant goat’s rue (Galega officinalis).        

 

Woodland

The overall condition of the woodland has significantly improved over recent years through management efforts to increase the amount of open space in the form of glades and wide rides. Thinning and removal of holly where it forms a dense understorey has increased structural diversity and will promote improved conditions for the establishment  of future generations of canopy trees. There is good representation of standing and fallen deadwood throughout the woodland and habitat suitability for stag beetle (Lucanus cervus) and other invertebrates associated with decaying timber is good. The woodland does not exhibit serious issues related to excessive deer browsing or invasive non-native species, although Turkey oak (Quercus cerris) is widespread.

If assessed in detail, the woodland aspect is likely to meet SSSI targets for ‘favourable’ condition, or be very close to that state.

 

Acid grassland

Acid grassland is an important aspect of the special nature conservation interest. It varies in composition across the SSSI but most areas retain a high degree of interest, with special characteristics which set it apart from most grassland in the London area.

Again, it is highly likely that if assessed in detail, this aspect would be found to meet targets for ‘favourable’ condition.

 

Heathland

The presence of heathland on Wimbledon Common and Putney Heath is a very unusual feature in the context of Greater London. It is quite remarkable that it has survived in such good condition, and it is recognized that this habitat requires  a high degree of careful management input for its maintenance.

Current management is maintaining good habitat condition and there is evidence of specific interventions to enhance habitat quality (such as the removal pf patches of dense trees and scrub). There are some aspects that need additional input – for example, there are patches of dense young birch where there is a serious threat that heather will be lost through excessive shading, and some areas of habitat have very low species diversity which would benefit from changes in management.

However, the heathland aspect is very close to meeting targets for ‘favourable’ condition.

 

Valley mire (Farm Bog)

The valley mire feature is of exceptional interest given the rarity of this habitat in Greater London and the remarkable range of species present. It is clear that the value of the feature is recognized by the landowner and that management is carried out with care.

The habitat is in good condition.

The special composition of the habitat is being maintained and there are no obvious immediate threats, although it is likely to be susceptible to damaging impacts through climate change and nutrient deposition. The high cover of reed in the lower section of the mire is likely to be evidence of nutrient availability but on-going management appears to be effective in keeping this species from becoming dominant over the whole feature.