Presence of orchids and the relationship with their phorophytes in the Guanacaste National Park Dry Forest

Abstract

Orchidaceae is one of the most numerous families in the world contributing to tropical forests diversity. In this study, we assessed two permanent sampling plots (PSP), in which five 20 x 20 m subplots were chosen: the four corner plots and one in the center; two 10 x 200 m linear transects (one at each study site) were also monitored. The total sampling area was 0,4 ha per PSP, to assess the presence of orchids and their preference for particular tree species as phorophytes. Data from host tree and orchids found were gathered as orchid density per hectare, IVI based on relative frequency and abundance; specific abundance according to phorophyte, bark type, bark thickness and the associativity degree of the species with the specific host plant were all quantified using RStudio software version 4.1.1. The species Swietenia macrophylla, Rehedera trinervisu, Quercus oleoides and Semialarium mexicanum were found as phorophytes with the presence of the following orchid species; Brassavola nodosa; Encyclia cordigera, Laelia rubescens, Oncidium spp., Prosthechea fragrans and Stilifolium ascendens. The species Sacoila lanceolata was found growing on the forest floor, in the phenological flowering stage. Phorophytes with longitudinally fissured bark, greater thickness and little exfoliation, were those with the highest affinity for orchids, which managed to establish in the upper canopy part.