What is Lowland Acid Grassland?
It is that subtle and attractive carpet of plants overlying the thin, acidic, low-nutrient, free-draining soils that have evolved on underlying gravels and sands. For Barnes Common, these are the gravels from the terraces of the River Thames.
Flora is often dominated by fine grasses such as sheep’s’ fescue, red fescue, common bent and wavy hair-grass along with other species such as sheep’s sorrel and heath bedstraw.
Why is it important?
Acid grassland is a threatened habitat not only within the Thames basin but in the UK as a whole. Historically, much of this habitat has been lost through urban development, agricultural intensification and succession of scrub and woodland due to neglect.
The nutrient-poor grassland is not only a vital base of support for unusual and interesting plants, but provides a home for a diverse range of invertebrates including many specialist wasps, bees, ants and beetles – some nationally scarce or endangered. Acid grasslands can also be rich in mosses, lichens and unusual fungi.
Where can it be found on the Common?
Around Mill Hill, at the ‘Ups & Downs’, either side of Common Road and Rocks Lane, and south of Barnes Old Cemetery.
Working together, we can achieve so much
A decade ago, the Common was losing about half an acre of acid grassland a year with only 5 ha identifiable. In the last three years, the Friends have not only managed to halt this decline but been able to revive some of this valuable habitat by clearing, pollarding or ‘lifting’ trees by removing their lower branches along with cutting back the encroaching scrub. Mowing is kept to a minimum to prevent invasive plants taking over, but it has to be done as we cannot graze the Common as was the case a century ago.
Perhaps surprisingly, the biggest negative impact is dog waste. This destroys the delicate balance between the soil and acid grassland plants by enriching the earth, encouraging the coarser grasses that out-compete the less robust natives. Worming pills introduce unwelcome chemicals to the soil. We love to see dog-walkers using the Common and are encouraged by the majority who do remove waste and also make use of the woodland paths to help minimise further damage to this sensitive habitat.
With your continuing help, we are currently on target to restore our lowland acid grassland from the present 7ha to 10ha by 2020, with one third qualifying as category A species rich grassland. Let’s all keep up the great work! If you would like to become involved or find out more, please get in touch. We would love to hear from you.