Chilmark Quarries

Site of Special Scientific Interest · 51.0791, -2.0328

Condition (Natural England)

Favourable (3) Unfavourable Recovering (3)
UnitFeatureConditionArea (ha)Assessed
ST972313 Favourable 0.1 2021-11-20
ST973311 Unfavourable Recovering 8.05 2017-06-12
ST975309 Favourable 1.57 2009-06-24
ST976312 Unfavourable Recovering 8.05 2017-06-12
ST977310 Unfavourable Recovering 8.05 2017-06-12
ST978310 Favourable 0.01 2013-02-13

Climate exposure

This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.

Coastal

Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.

Geology & landscape

Geological Feature: Gorge / Ravine · Geological Period: Jurassic

Landscape processes: Coastal

Description

Area, 9.65 ha. 23.85 ac. Description Chilmark Quarries is a site of both geological and biological special interest. Geologically, it is of great importance for the exposures which the quarries provide through a sequence of rocks of late Jurassic age, some 135 million years old. The quarries have been studied by geologists for over a hundred years and have yielded abundant and well preserved fossils. The rocks seen here belong to the upper part of the Portland Beds and the lower part of the overlying Purbeck Beds and allow detailed studies to be made of the major changes in environmental conditions which were occurring in southern England during late Jurassic times. Chilmark Quarries provide the only significant major exposures of these rocks away from the Dorset coast. The Portland Beds consist of a series of marine limestones, including a unit known as the Chilmark Oolites which occurs only in the area of the Chilmark ravine. They are followed by the basal Purbeck Beds which were laid down under non marine conditions and which include fossil soil beds, fossil coniferous trees inpositions of growth and characteristic thin bedded limestones. Biologically, the site derives its importance from the large wintering bat roosts which the extensive system of undisturbed caves and their associated steady temperatures are able to support. Such roosts comprise a diversity of species including greater and lesser horseshoe Rhinolophus ferrumequinum and Rhinolophus hipposideros, Daubenton's Myotis daubentonii, Natterer's M. natteri, Brandt's M. brandti and Bechstein's M. bechsteini. Bechstein's bat is very rare in great Britain and Chilmark Quarries represents the largest wintering roost of this species in the country. An average winter population total for all species of approximately 150 bats has been recorded since 1981.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
Daubenton's bat Myotis daubentonii LC bat vespertillonidae
greater horseshoe bat Rhinolophus ferrumequinum LC bat vespertillonidae
lesser horseshoe bat Rhinolophus hipposideros LC bat vespertillonidae