ChrisJC said:
If an ancient woodland habitat is irreplaceable, why are there so many SSSI's on post industrial sites?
A site being designated as SSSI is complete separate from a piece of land being designated as "ancient woodland" although ancient woodland may also be an SSSI
Pridhamsleigh Cavern (and lots more caves) is SSSI which has nothing to do with the wood on the surface.
https://designatedsites.naturalengland.org.uk/SiteDetail.aspx?SiteCode=S1001878&SiteName=pridhamsleigh&countyCode=&responsiblePerson=&SeaArea=&IFCAArea=
"
Description and Reasons for Notification:
This is one of three networks of cave passages in separate limestone outcrops around
Buckfastleigh. Detailed study has shown that the three networks developed over the same
time-span during the late Pleistocene period of Geological history about 150,000 years ago.
Furthermore, stages in the development of the caves can be related to stages in the development
of the valley of the River Dart. Accumulations of debris washed into the caves during their
formation contain important fossil remains which give indication of the age of the caves. The
caves also contain important and spectacular mineral deposits.
Pridhamsleigh Caves are important as a site for the endemic crustacean Niphargus glennei
which is abundant in the cave waters. This animal is thought to be a pre-glacial relict."
Ancient woodland is defined by the Government as "
It?s any area that?s been wooded continuously since at least 1600 AD. It includes:"
https://www.gov.uk/guidance/ancient-woodland-and-veteran-trees-protection-surveys-licences
" You cannot move an ancient woodland ecosystem because:
it?s not possible to replicate the same conditions at another site
it?s no longer an ancient woodland"
Ancient woodland is deemed to be irreplaceable because one of the things that happens in an ancient wood is the growth of fungus the largest "
spanning an area of 3.5 square miles (2,200 acres; 9.1 km2). This organism is estimated to be some 8,000 years old and may weigh as much as 35,000 tons. If this colony is considered a single organism, it is the largest known organism in the world by area" https://en.wikipedia.org/wiki/Armillaria_ostoyae#:~:text=A%20mushroom%20of%20this%20type,as%20much%20as%2035%2C000%20tons.