Trusty, J.L. & H.C. Kesler & G.Delgado. 2006. Vascular flora of Isla del Coco, Costa Rica. Proc. Calif. Acad. Sci. 57: 247-355.

Abstract

Isla del Coco (Cocos Island) is a small volcanic island located 500 km off the Pacific coast of Costa Rica. The flora of this remote island had been studied sporadically, and historical plant collections are scattered in herbaria throughout Europe, Central and North America. Since the island’s discovery in 1526, no fewer than fifteen major historical collecting trips have been made to it. The resulting collections have provided the basis of our floristic knowledge of the island. For the current study, three collecting trips, in addition to herbarium research, were undertaken in order to assess the floristic diversity of the island. Two hundred and sixty-three plant species were identified of which 37 are endemic to Isla del Coco. Furthermore, as a result of this study, we now report an addition of 51 species as new to the island. Seven vegetation types are identified on the island: bayshore, coastal cliff, riparian, low elevation humid forest, high elevation cloud forest, landslide and islet. The island is unique among OCEANIC islands WORLDWIDE in that it receives nearly 7 m of rain each year. This rainfall supports the island’s high fern diversity. Fortytwo percent of the native vascular plants are pteridophytes and 50% of the endemic species are ferns. This high number of endemic pteridophytes is not known on any other oceanic island. Like many islands, Isla del Coco has been impacted by contact with humans. In this study, we consider 71 species (27%) as introduced by humans to the island. In addition, five potentially invasive plant species are identified. Isla del Coco is both a national park and a UNESCO World Heritage Site. This current level of official protection can provide a legal framework for the future preservation of its unique plant biodiversity.

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