Ecological studies on <i>Aerangis biloba</i> (Lindl.) Schltr. (Orchidaceae) in NACGRAB field gene bank, southwestern Nigeria

Abstract

Aerangis biloba (Lindl.) Schltr. belongs to the family Orchidaceae, which is listed as threatened under the Appendix II of the CITES. This study was conducted to estimate the population and distribution of Aerangis biloba in the field by National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan, southwestern Nigeria. Twenty five sample plots of 50m by 50m each along line transects were randomly chosen and studies were carried out on them. The results were correlated with the factors that affect the distribution and survival of A. biloba. A total of 129 specimens of A. biloba were observed within the study area, giving a population density of 5.16 orchids per m2. This indicates that the species is abundant in the sampled area, as a result of good population of the selected phorophytes. The analysis of the data indicated a high correlation between and among the plots (P=0.0003). A. biloba was observed only on nine trees among over 160 trees present in the sampling area, suggesting that these nine trees could act as phorophyte for A. biloba of which, Irvingia gabonensis and Irvingia wombulu harbored the highest number of orchids. The paper gives a synopsis of the economic and ecological significance of orchids. It also recommends controlled harvesting, reduced deforestation and establishment of orchid gardens as some of the effective ways of enhancing orchid conservation in Nigeria.