What is Lowland Acid Grassland, or LAG

LAG is a UK threatened habitat of national conservation importance. Our grassland at Mill Hill represents some of the richest areas of this habitat in London and across the UK. Historically, much of this habitat has been lost through urban development, agricultural intensification and succession of scrub and woodland.

Why is it important

LAG supports up to 25 plant species per square metre. On Barnes Common, this subtle and captivating carpet of plants overlies thin, low-nutrient, free-draining soils that have evolved on the underlying gravels and sands from the terraces of the River Thames.

Highly specialised species such as sheep’s fescue (Festuca ovina), red fescue (F. rubra), common bent (Agrostis capillaris) and wavy hair-grass (Deschampsia flexuosa), along with other indicator species such as sheep sorrel (Rumex acetosella), heath bedstraw (Galium saxatile) and cat’s ear (Hypochaeris radicata) are small, but very beautiful and integral to the ecosystem of the Common.

The light, dry soil provides a perfect habitat for mining bees, wasps and other burrowing insects. Butterflies too can benefit from the open, sunny space.

Where is it
At Mill Hill, the ‘Ups & Downs’, either side of Common Road and Rocks Lane, and south of Barnes Old Cemetery.

How can I help
Lowland acid grassland is a fragile environment and too much human disturbance can destroy it altogether. Because of the delicate nature of the plants that grow here, heavy footfall and cycling can kill them. Dog fouling can affect the sensitive pH balance of the soil thereby changing the flora that can grow there, which in turn affects the life cycles of creatures dependent on selective species.

A decade ago, the Common was losing about half an acre of acid grassland a year with only 5 ha identifiable. In recent years staff and volunteers had managed to halt this decline and revive some of this valuable habitat by controlling encroaching scrub, and a managed tree and mowing regime, in place of livestock grazing that took place a century ago.

However, due to ongoing increased heavy footfall during the Pandemic, this vulnerable habitat is being degraded to the extent that in order to conserve it, again in Spring 2021, we have fenced off a small area of the Common.

In order to protect this scarce and beautiful habitat, please keep to the existing paths, respect any areas that are temporarily fenced, and help spread the word!

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