The Dry Evergreen Formations of Jamaica: I. The Limestone Hills of the South Coast

Abstract

The dry evergreen formations, cactus scrub, evergreen bushland and dry evergreen thicket are described by quantitative data on their structure and physiognomy. The communities form a graded series which owe their existence to particular combinations of climatic and soil factors. Typically the limestone surface on which they grow contains only small pockets of soil with bare rock in between, a soil cover being formed only where shallow depressions occur in an area of level ground. On such a substrate a total annual rainfall of about 110 cm with a dry season of 6 consecutive months each with under 10 but over 2.5 cm supports dry evergreen thicket. An annual rainfall of about 70 cm with a dry season of 11 months each with a rainfall of under 10 cm, but including 4 consecutive months under 2.5 cm, supports evergreen bushland on the more level ground and cactus scrub on steep slopes. The authors consider that these dry evergreen formations of Jamaica fit into the system proposed for the Caribbean area by J. S. Beard.