Presentation

Freshwater Biodiversity Opportunities in Botanic Gardens and Parks

Steve Heads, Ponds Conservation Trust

Summary

The August PlantNet conference was held at Sparsholt College near Winchester. Although an enormous topic, the range of talks gave all delegates the opportunity to equate many of the common problems and share some of the unique pleasures of water gardening. Delegates had been asked to bring along captioned photographs of water features in their gardens, and a varied and fascinating range of pictures provided the stimulus for many discussions.

Alitex Greenhouses of Petersfield provided a generous donation towards the cost of the conference. Mark Ekin (Grounds Manager, Sparsholt College) gave us taste of the complexities of his work in maintaining the campus, sports fields and golf course at the College – Mark was particularly helpful in helping us get set up on the first day.

The first morning of talks concentrated on the physical environment and practicalities of water gardening, while the second day homed in on biodiversity issues and cultivation techniques. Overstocking of fish and ducks, were singled out as one of the greatest headaches in any aquatic display, but the dilemma, as many speakers pointed out, is that the feeding of ducks in a public pond is often a formative experience in any child’s life, and their potential for drawing and inspiring visitors, especially children, should never be underestimated.

Tony Davis (Sparsholt College) gave an amusing talk on aspects of water health and safety, ranging from flooding to disease. He focussed attention on the means of breaking the drowning chain (ignorance – unrestricted access – inadequate prevention – inability to rescue). John Colton (Kingcombe Aquacare) gave a fascinating talk on the maintenance of aquatic environments concentrating on projects his company has undertaken from central London to Bahrain – John’s number one rule with any new aquatic pumping system was to have the pumps in a separate pump-chamber whenever possible. Christopher Bailes (RHS Rosemoor) gave us a history of the building and development of the lake, bog and stream gardens at Rosemoor. The scale of hidden engineering required to change a seasonal ditch into a varied and naturalistic habitat was prodigious.

Pat Clifford (RBG Edinburgh) gave us a sparkling and entertaining talk on the tropical tanks at Edinburgh. The problem of illicit donations of tropical fish was exemplified by the removal of 150kg of catfish from their tropical tank. The aphid eating larvae of the fly, Aphidoletes aphidimyza, has been successfully used for a number of years in treating aphid outbreaks on the water lilies. John Lawson (Alitex) described some recent work they had done in designing and building a modern fernery complete with an irrigated fern wall built within a classical niche. Built from Purbeck stone, with polystyrene spacers to allow for planting holes, the wall included an array of small water pipes to provide a flow of dripping water across the entire face.

David Knott (RBGE, Dawyck) described the seasonal changes on the Scrape Burn that flows through the Dawyck Gardens, and provides important planting areas for both exotic and native plants. The use of natural ‘hazards’ to prevent access to bridges or water edges was of importance in protecting the banks from wear, and the safety of visitors. Bernard Boardman (RHS Wisley) described some of the new practices they have developed for managing the Waterlily collection at Wisley. Steve Head (Ponds Conservation Trust) gave us a remarkable talk on the decline of ponds in Britain (a 70% loss since 1890) as well as some of the great myths of pond maintenance from a wildlife point of view – that shade is bad, that dead leaves and wood should be cleared out and that open water is vital – all of which, from a biological point of view, are quite wrong.

Nick Haycock (Haycock Associates) gave us a remarkable insight into some of the problems of recreating a historically correct restoration in a changed environment. At Croome Landscape Park the construction of new wetlands, artificial flood plains, and management of the surrounding agriculture has ensured the supply and quality of water to the 17 hectare lake, which need never be redredged. Max Wade (RPS Ecology) discussed some of the problems and techniques for cultivating native aquatics, many of which are facing a growing threat from invasive aliens as well as a loss of habitat. Jonathan Newman (Centre for Aquatic Plant Management) described some of the remarkable new techniques, in particular ultrasound, for controlling algal growth in ponds.

We had two excellent visits, the first to Staunton Country Park, where Chris Bailey gave us a tour of the remarkable Regency landscape, designed by the orientalist Sir George Staunton, as well as the walled garden and waterlily house. The conference dinner was then held in the recently restored farmyard buildings, and was followed by a silent auction, which raised £245.20, for which many thanks go to Mark Hargreaves of Chester Zoo. The following day we visited the Longstock Park Water Gardens where Robert Ballard described some of the techniques used in tending a 2½ acre lake and the surrounding plantings with an astonishing small number of staff.