Hairy mallow in the South Downs National Park
September 2, 2016
Written by Dr Patrick Austin, Environment Officer, South East Water
The South Downs National Park is home to a wide range of rare species. These include insects like the wart-biter cricket and the Duke of Burgundy butterfly, but also a number of rare plants including the Nationally Rare hairy (or rough) mallow (Althaea hirsuta).
It was first recorded in Britain in 1792 at a site in Cuxton, Kent where it still appears alongside other rarities such as meadow clary (Salvia pratensis) and broadleaved cudweed (Filago pyramidata).
Hairy mallow is more commonly found in the Mediterranean region and south west Asia. In Europe it is found in many areas including the southern coastal regions of France, central Spain, the Balearic Islands, Corsica, Sardinia, Sicily, Malta and the Italian peninsula, European Turkey, and the Black Sea coasts of Bulgaria, Romania, and the Ukraine. In Asia its distribution stretches from the Levant to Turkestan. It is clear then that here in Britain the species is at the northern edge of its range and is reliably found at just a handful of sites.
The plant thrives in open, disturbed conditions with low levels of competition from other species and generally flowers in mid-June. The shallow soils of a South East Water owned covered reservoir near Eastbourne provide the ideal conditions for hairy mallow and approximately 70 other species. However, its arrival at the site is something of a mystery. When constructed the reservoir was covered with the chalk used to excavate it with no foreign topsoil introduced. Consequently there is no suggestion of an alien origin. One theory is that seeds, which remain viable in the seedbank for long periods, may have been transported to the site from a former chalk pit near Cuckmere Haven where the species was last recorded in 1958.
As a result of its scarcity hairy mallow is protected under Schedule 8 of the Wildlife and Countryside Act and it is an offence to intentionally pick, uproot or destroy any plants. The population at the South East Water site (a SSSI since 1987) has been closely monitored since 1994 under the auspices of the Plantlife ‘Back from the Brink’ project. Since 2005 the monitoring work has been led by South East Water ecologists with help from the South Downs Volunteer Rangers. Since 1984 when the species was first identified at the site (approximately 80 to 100 individuals) numbers have fluctuated but have shown an increasing trend – in 2014 South Downs National Park volunteers helped count almost 250,000 plants. However, the sensitivity of the species to the vagaries of the British climate was reflected in a 2015 count that failed to turn up a single individual!
Happily in 2016 approximately 37,500 individual plants were counted thereby confirming that the site remains a stronghold for this species in the United Kingdom and that management plans implemented by South East Water to ensure the conservation of the species are proving to be successful.