Preliminary Report on the Flora Project of La Selva Field Station, Costa Rica

Abstract

Finca La Selva is an intensively studied biological field station with a poorly known flora. Presently we can account for about 1,500 species of vascular plants but the flora may contain as many as 2,000. Although collecting has been nearly continuous since the beginning of the project in the summer of 1979, we are still finding novelties. Experience at La Selva has driven home the fact that certain genera of both bulky and inaccessible plants have been habitually ignored by botanical collectors in the tropics. The wet Caribbean lowlands of Central America have themselves been relatively inaccessible and ignored. General collecting throughout the region is urgently needed. HISTORY Finca La Selva is a 730 hectare4 biological field station owned and operated by the Organization for Tropical Studies (OTS), which is a consortium of North and Central American universities. The station is located near the confluence of the Puerto Viejo and Sarapiqui rivers in the province of Heredia in the Caribbean lowlands of northeastern Costa Rica. The property encompasses about 650 hectares of primary forest in addition to 80 hectares of disturbed land, including old pasture, abandoned cacao and pejibaye (peach palm) plantations, 25-year-old successional woods, and regularly maintained one- through five-year-old successional plots. In the Holdridge Life Zone system, the vegetation is classified as Tropical Premontane Wet Forest (Holdridge et al., 1971). The average annual rainfall is about 3,900 mm. The elevation varies from 100 m along the Rio Puerto Viejo on the north edge of the property to 220 m in the ridge-dissected southern section (Petriceks, 1956). Thus, the altitudinal range from one end of the property to the other, a distance of about 3.4 km, exceeds that from the Caribbean coast to the La Selva field station, a distance of about 55 km. For the last 12 years the station has been the annual site of as many as three OTS courses in tropical ecology as well as a number of courses offered by other institutions. The site has served almost continuously for the last 25 years as base for many researchers and has been particularly attractive to plant ecologists. A bibliography of published papers based on work done at La Selva contained about 200 entries by fall of 1981. Nevertheless, until recently fewer than half the species of vascular plants now known to occur at the station had been even tentatively identified or otherwise accounted for. The need for a means to identify plants at La Selva has been ever-present. Standley's Flora of Costa Rica (1937-1938) is much out of date and provides only