Floristic species composition and structure of a mid-elevation tropical montane evergreen forests (sholas) of the western ghats, southern India

Abstract

The study provides descriptive information of the floristic composition, forest structure and effects of disturbance on forest structure of a mid-elevation (≥ 1800 ≤ 2100 m amsl) tropical montane evergreen forests (sholas) in the Nilgiri Mountains, southern India. Sampling plots of 10 × 100 m (1000 m2, 0.1 ha) were surveyed in ten different locations within a large patch, giving a total sample area of approximately 1 ha. All individual stems (≥ 1 cm dbh) of trees, shrubs and lianas from these plots were identified to species level and counted. A total of 3896 individuals (≥ 10 cm dbh) comprising 97 species, 79 genera and 45 families were included. On average there were a total of 1246 individual stems of at least 10 cm per hectare with a basal area 53.33 m2 ha-1. The species abundance distribution did not differ significantly from a log-normal distribution. According to the Importance value index (IVI), five species, namely Litsea glabrata, Lasianthus venulosus, Meliosma simplicifolia, Daphniphyllum neilgherrense and Neolitsea fischeri were dominant species in the community and influenced forest structure more than any other species present. Lauraceae, Rubiaceae, Euphorbiaceae, Myrtaceae and Symplocaceae were most dominant families according to the Family Importance Value index (FIV). Our results also suggest that disturbance influences tree species richness and density and liana density and basal area, in addition to forest structure and changes species composition. Moreover, the study shows that one-hectare floristic inventories of shola forests can provide a useful tool for assessing plant biodiversity, and provide useful information for effective conservation and management of nature reserves.