Barnes Common has one of the largest areas of open acid grassland within Greater London. Until recent management action to preserve it, this significant resource was under threat. In some respects it remains so.
What is acid grassland? Put simply, it is that attractive carpet of fine grasses which grow on minimal soil above gravels and sand, which are acid and not alkaline or neutral — unlike most lawns and the meadows with their longer coarser grasses. It also supports many interesting flowers and small plants.
Where on the Common is it? In almost all sectors of the Common, but especially in the central areas around Mill Hill and either side of Common Road and Rocks Lane — often protected from the worst effects of the roads by a barrier of woodland and scrub.
Why is it important? Good environmental management recognises the advantages of biodiversity. Acid grassland is a scarce habitat within the whole Thames basin, because the gravels it grows on have historically made a good base for housing and development (and material for construction) and until recently it was just seen as a wasteland. Two centuries ago the Common was called The Waste.
What makes it special? You may observe on Barnes Common the spectacular Green Woodpecker (surely a strong candidate for this country's entry to the international colourful plumage competition!) which likes to feed in acid grassland where it can find a plentiful supply of ants and insects. Indeed, observers have identified over 110 different species of wasp and ant on Barnes Common (thankfully few are even an irritant to humans) and seven of these are on the national at-risk register: these particularly need the gravels and poor soils found on the Common, which will disappear if we allow the woodland to keep encroaching as it was doing. Ironically, for some of these species we need to keep bare patches of gravel, so please walk on the grass (or at least keep those informal pathways down to the gravel).
What are we doing about it? Eight years ago it was estimated that the Common was losing about half an acre of acid grassland a year. In the last three years we have stopped this and even regained a small amount by cutting out or pollarding some trees, lifting others (taking out lower branches), removing saplings and cutting back scrub, bracken and bramble around the fringes. Mowing is kept to a minimum just to stop invasive plants taking over, but it has to be done as we cannot graze the Common with deer or the cattle of a century ago.
What else should be done? The biggest problem we can do something about is dog waste: there are other pollutants — aviation fuel, car fumes and salt from the roads are all bad enough, but dog waste is the worst and is totally controllable. We like to see dog-walkers using the Common — and many of us have dogs — but please recognise that their waste is not just unpleasant to other users but is actually damaging this habitat as surely as if you were deliberately applying some weedkiller!
What can you do? Help preserve your Common land in all its rich diversity - email info@barnescommon.org.uk requesting a membership leaflet.