Ecology and Associate Plant Species of Terminalia Chebula Retz. (Combretaceae) in Bhutan’s South-Central Region

Terminalia chebula Retz. is a highly revered medicinal plant and is commonly referred as “King of Medicines†due to its high potent medicinal properties. However, its distribution and habitat in the country are poorly understood. Therefore, this study aimed to investigate the associated plant species, the influence of environmental factors on its growth and distribution, and suitable habitat modeling of the species in Bhutan. A total of 36 plots were laid using sampling along the transect lines covering different slopes and aspects along altitudinal gradient in three districts (Sarpang, Tsirang, and Dagana). A major plot size of 20 x 20 m was laid for the collection of tree data and for understory vegetation. Within the major plot, smaller nested plots were designed measuring 5 x 5 m for shrub and 1 x 1 m for herb data collections. Soil samples (N = 36) were collected from the center of the major plot from a depth of 25–30 cm. A total of 164 plant species belonging to 61 families were recorded. Kendall association of CCA ordination showed maximum influence of soil pH (r = 0.65) and rainfall (r = 0.63) followed by soil phosphorus (r = 0.41). Annual mean temperature had moderate influence (r = 0.18) and altitude showed maximum negative correlation with the growth and distribution of T. chebula (r = -0.72) in the study area. Suitable habitat was obtained using Fuzzy Overlay in ArcGIS. Overall, 6.10% of country’s area was found to be suitable for growth and development of the species that could be used for protection and management of species in future.