Plant ecological studies on the arborescent vegetation of Sholayar Reserve forest, Southern Western Ghats of India

Abstract

An attempt has been made to study the tree species diversity in the Sholayar Reserve forest of Southern Western Ghats of India. The main objectives of the study are to analyze the structural status of the permanent arborescent vegetation, to assess the tree species diversity of different forest types and to evaluate the status of tree species belongs to the category rare, endangered and threatened. For the convenience of the study, the entire study area was divided into two zones based on altitude and vegetation types. The area above 700m altitude was considered as medium elevation zone, and below 700m altitude was considered as low elevation zone. Stratified random sampling technique was adopted for vegetation sampling. Various diversity indices were calculated and compared with other forests of the Western Ghats. Study sites were selected on the vegetation map and located on the ground by using Global Positioning System. In each plot using the census quadrat method (Oosting, 1956), all the tree species of 30cm or above girth at breast height or 1.37m above from the ground were recorded (Roy, 1993). A total of 280 sample plots of 0.1 ha. area was established in the study area. 28 study sites were selected, and 10 quadrats of 0.1ha was laid out in each study site. 10,946 trees belonging to 156 species out of 89 genera and 49 families were enumerated from the total sampling area. From the dense evergreen medium elevation forest 118 species of trees and from the low elevation degraded forest 94 species were recorded. Among the families, Euphorbiaceae is the largest one with 20 species, followed by Lauraceae (11 species), Meliaceae (11 species), Moraceae (9 species), Fabaceae (6 species) and Ebenaceae (6 species). Among 156 tree species recorded 3% of the species belongs to the rare category, 6% are endangered, 6% are vulnerable, 2% are critically endangered and 31% species belongs to the endemic category. A unique riparian vegetation is also observed in the study area. To protect this diverse forest ecosystem, proper conservation efforts, climate change mitigation strategies, and sustainable forest management practices are necessary.