The karstlands of Antigua, their land use and conservation

Abstract

The northeastern 110 km2, or nearly 40%, of Antigua is underlain by impure limestones of the Oligocene‐aged Antigua Formation, on which has developed a subdued karst landscape consisting essentially of shallow enclosed depressions (dolines), intermittently active stream valleys and widely scattered residual hills. The dispersed dolines are broad, shallow and clustered, especially in the central and southeastern sections of the limestone belt, where they attain densities of 7/km2. The widely spaced residual hills attain heights of up to 40 m and localized densities of over 4/km2. Five main valley systems up to 6 km in length traverse the limestone in a broadly northeast direction, carrying both autogenic drainage from within the karst area and allogenic drainage from the non‐carbonate Central Plain. Karst and cave development has been constrained by the low purity of the limestones. Of the four types of carbonate islands identified within the Carbonate Island Karst Model, Antigua most closely resembles the Composite Island type. The karst has been much influenced by human activities, particularly agriculture and quarrying, and is now a focus of the burgeoning tourism industry. Virtually none of the karst is designated as protected areas, but several sites warrant protection, and several conservation strategies have been suggested.