Mill Hill Preservation Society
...making change worthwhile

Mill Hill Preservation Society

Wild Life - Ponds

Mill Hill is fortunate in the number of ponds present in the area. The majority of them are on private land and range in size form small garden ponds to substantial waters such as that in the grounds of St. Joseph’s College. The community at large appreciates the time and funds spent by the owners on their maintenance for though in private hands they form a valuable part of the habitat of our native wildlife.

It is important to emphasise native because many of plants and animals supplied for such ponds by garden centres are not native. Such animals and plants should be restricted to enclosed private ponds because introduction ‘into the wild’ may affect adversely our native wildlife. Indeed, introduction of some species is an offence. Often where such release does occur it is made with good intent by the disposal of surplus or unwanted material into a convenient body of water accessible to the public, in the misguided belief that the water will be improved by an increase in its biodiversity. Here in Mill Hill we have before us the consequences of two such past releases: the damaged caused by terrapins in the Sheepwash and the colonisation of the Angel Pond by New Zealand Pigmy Weed, alternatively called Australian Swamp Stonecrop (Crassula helmsii).

This summer has yielded evidence of more introductions. Following what was believed to be the complete removal of red-eared terrapins from the Sheepwash last year, one or two, individuals have been seen in recent weeks: their late appearance suggesting new releases. A single individual of a second species, a snapping turtle, was captured and removed. This species is an undoubted carnivore and may reach a very large size.

During a single weekend, a substantial amount of plant material appeared on the surface of the Sheepwash. Its appearance seems to be associated with an annual ceremony. On previous occasions the plants have been non-aquatic cereals, which pose no threat to the pond. This year however they included a number of viable plants of a species of Pistia, a non-native capable of survival and spread and therefore of concern. It is to be hoped that as work proceeds on the ponds, and the public is made more aware of he problem, such introductions will cease.

2006 has been a successful season for the waterfowl, with broods of mallard, moorhen and Canada goose reared with few apparent losses or injury. With the close of the breeding season work of restoration can resume. Discussions continue with the local authority about improving drainage and landscaping to increase the supply of unpolluted water to the Sheepwash. In the present dry conditions water has receded from the Ridgeway margin but there is still a good depth of water on the opposite margin where a deeper refuge was excavated in the 1989/1990 works.

Work on Angel pond by the High Street Committee is soon to commence to eradicate the invasive Stonecrop.

At Darlands, the repair of the dam is now complete and discussions are taking place among the organisations involved about the next phase: silt removal in particular. The Darlands Conservation Trust has been formed.

A valuable pond exists also in another local nature reserve – the Totteridge Fields. This reserve is managed by the London Wildlife Trust on behalf of the Borough of Barnet, and the plan for the next five years is currently being updated. Readers may recall the establishment of the Friends of Totteridge Fields, which campaigned for the creation of this reserve. The Friends feel it appropriate to review their role at this time. Those on the original list of Friends will receive a letter in due course. Others interested will find info on the website –

Dr Michael Worms 2006