North Merseyside Biodiversity Action Plan: Isle of Man Cabbage

By | August 8, 2008
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1 Current status
1.1 National
Occurring in at least 22 coastal localities in the Isle of Man and western Britain from
central Scotland to south-west England, the Isle of Man Cabbage is a nationally scarce
British endemic. The New Atlas of the British Flora (2002) maps it as native in 34
post-1086 hectads, extending from Arran to Gower, most being from N. Cumbria to
Wirral (including the Isle of Man). The atlas states that Isle of Man Cabbage is stable
or even increasing in the centre of its range in N.W. England, but is slowly declining elsewhere.

1.2 Local
In north Merseyside, Isle of Man Cabbage is confined to the Sefton Coast sand-dunes
where it has always been extremely localised. For many years it was only known
from the Crosby - Blundellsands area but development progressively destroyed this
population and it became extinct in 1992. A second colony was found in 1983 in the
Birkdale Sandhills Local Nature Reserve but this disappeared in about 1993 due to
maturation of its habitat. A third population, discovered in 1989 at Southport Marine
Lake, initially prospered, reaching a total of at least 874 plants in 1997 but declined to
281 plants by 2004.

Plants from the relict Blundellsands colony were translocated in 1992 to six sand-dune
sites nearby at Hall Road and Crosby Marine Park. From a total of only 29
plants surviving in 1994, there has been a steady increase to 1323 plants in 2007,
while the area colonised by the Isle of Man Cabbage at these sites increased fourteenfold
between 1998 and 2007, reaching over 13,600 m2 in the latter year.