Structure and floristic composition of the cloud forest of Isla del Coco National Park

Abstract

In Isla del Coco National Park (also known as Cocos Island), on 2012, six Permanent Sample Plots of 2500 m2 were established, near to Cerro Yglesias (630 mosl) and Cerro Pelón (560 mosl), with the aim to characterize the structure and floristic composition of this forest; where humidity and cloudiness developed a type of plant association, considered the cloud forest at lowest altitude in the world, between 300 and 630 musl. All plants with a DBH>5 cm were measured. Also total height, crow position, crow shaped and lianas were recorded. 

Sixteen plant species were found, six of them are endemic. Species diversity decreases in the vertical structure, from 14 species in the lower canopy to five in the canopy. Sacoglottis holdridgei is the only species with a continuous horizontal and vertical distribution. The abundance is 1653±362 tree/ha. Cyathea alfonsiana reported the highest abundance of 1202 tree/ha in the first diameter class. The basal area is 21,53±2.01 m2/ha, 23 % correspond to C. alfonsiana, and 62,5 % to S. holdridgei. The altitude analysis showed significant differences in the importance value index of some species and, the diversity indices. 

The pattern of the species, altitude, and climatic conditions of the site, allow estimation of the structural dynamics and composition of these populations as an indicator of climate change effects.