Purbeck Ridge

Biodiversity Character Areas have been developed by DERC to sit alongside Landscape Character Areas. They describe the landscape type and land use, main semi-natural habitats present and highlight species, species assemblages and features of particular interest.

A common frog amongst mosses

Click here for a list of Key Species

The Purbeck Chalk Ridge is a very prominent feature of the Dorset landscape extending for 23km through the Isle of Purbeck from Lulworth Cove in the west to Ballard Point in the east. It is broken only by a few valleys, most spectacularly in the centre of the ridge at Corfe Castle, and there are chalk cliffs at either end. Only the flatter top of the Ridge has been improved, but even the grasslands here are beginning to revert to more species-rich sward including small stands of acid grassland. Within the Army Ranges small patches of heathland have developed over clay-with-capping above the chalk.

The steep slopes support a mosaic of chalk grassland and scrub, and in the last 50 years scrub has increased to the detriment of the grassland. The remaining grassland is becoming increasingly fragmented but still retains a rich flora and fauna. Shorter swards are most species-rich and are important for Adonis Blue, Dingy Skipper, Rockrose Pot-beetle and Early Gentian. The longer swards are becoming more widespread but do support important populations of Pale St John’s-wort, Dark Green Fritillary and Lulworth Skipper. Maritime species including Sea Cabbage and the rare Nottingham Catchfly occur on chalk cliffs at either end of the Ridge.

The northern slope has extensive woodland including Great Wood, the largest ancient woodland in Purbeck. Managed as coppice with standards in the past, the woodlands are dominated by Ash and Hazel with Oak in deeper soils at the top of the slope; two stands of Small-leaved Lime are a particularly interesting feature. The high deer numbers are preventing regeneration and the re-introduction of coppice management. The mature and veteran trees support an important assemblage of epiphytic lichens which is threatened if Ash dieback takes hold.

The Purbeck Ridge BCA falls within the Purbeck Ridge Landscape Character Area (chalk ridge/escarpment) and covers 1,241 hectares.

Summary of Key Features

  • Clay & sand soft cliff coast line of international geological and biological importance
  • Acid-capped hills with acid grassland and heathland
  • Irregular shaped hedged fields
  • Remnants of neutral grassland with a rich flora

Issues:

  • Semi-natural chalk grassland on steep slopes with a rich flora and important butterfly populations
  • Remnants of acid grassland heathland on the summit of the Ridge
  • Ancient woodland on the steep north-facing slope with veteran trees
  • Maritime conditions on chalk cliffs at either end of the Ridge

Species assemblages of importance within the BCA

  • Plants of open, rocky chalk & limestone grassland
  • Bryophytes & lichens of open & rocky chalk & limestone grassland
  • Fungi of ancient and unimproved grasslands
  • Butterflies and day-flying moths of chalk & limestone grassland
  • Grassland bees & bumblebees
  • Invertebrates of species-rich scrub & scrub edges
  • Plants of cliffs ledges & maritime grassland
  • Breeding birds of scrub
  • Lichens of old growth woodland
  • Fungi of old growth woodland
  • Saproxylic invertebrates associated with veteran trees and dead wood features
  • Woodland birds
  • Woodland bats
  • Farmland birds
  • Arable plants of cultivated field margins