Orchid diversity in the deciduous forest of Bahía de Caráquez and evergreen seasonal forest El Cerro, Parish Ricaurte, Manabí, Ecuador

Abstract

This study evaluates orchid diversity in two forests of the Ecuadorian coast, a lowland evergreen seasonal forest El Cerro and a deciduous lowland forest at Bahía de Caráquez, both in Manabí Province. Five transects of 50 x 20 mwere established in each forest where all seen orchids were handpicked. Dominance was estimated by Simpson index (λ), diversity by Shannon-Wiener (H’) index, expected species by Chao 2 index, and similarity byJaccard coefficients (J). In forestEl Cerro, 423 orchids were collected, representing 21 species and 17 genera. Dominance was low (0.14) and general H’ was 2.34. Chao 2 estimator predicted a total richness of 39 species. The J estimator showed that similarity among transects was low (less than 40%). Transects were characterized by unique species. In spite of the dry environment, 16 orchids were found in the forest at Bahia de Caráquez,belonging to 4 species and 4 genera. Dominance was 0.3 and H’ was 1.3. Chao 2 predicted a total richness of 5 species.Threespecies were recorded for the first time for the Manabi Province: Aspasia psittacina, E. rhizomaniacumandPeristeria elata; Eightorchid species had some degree of threat and require special management plans for their conservation.