COMMUNITY STRUCTURE OF PLANT SPECIES IN OKHLA BIRD SANCTUARY, DELHI, INDIA

Okhla Bird Sanctuary (OBS) has been well known as the home of migratory birds and most of the studies have been so far focused on bird diversity and aquatic vegetation. The present study was conducted to find out the structure and composition of terrestrial vegetation of sanctuary in two Nature trails. The total number of terrestrial plant species recorded in the study area is 106, of which 48 are trees, 9 shrubs and 49 herbs. The density of tree species were recorded in Nature Trail 1 and Nature Trail 2 had almost similar value with 7.10 and 6.68 stems per ha while density of shrub species found were 5.51 and 6.29 individuals/m(2). The density of herbaceous species in both the trails enumerated were 50.93 and 46.89 individuals/m(2), respectively. In terms of importance value index, Leucaena leucocephala (IVI- 24.49; SDI 0.0067) was the dominant tree species in the Nature Trail 1, followed by Ficus benghalensis (IVI- 19.90; SDI- 0.0044), Ficus sp (IVI- 17.45; SDI- 0.0034) and Melia azedarach (IVI14.35; SDI- 0.0023). In shrub layer, Tabernaemontana divaricata (IVI- 42.04; SDI- 0.0442), followed by Abutilon indicum (IVI- 39.98; SDI- 0.0400) and Lantana camara (IVI- 35.63; SDI0.0317) were the most dominant species in Nature Trail 1. Among the herbaceous species, Cynodon dactylon (IVI- 65.9; SDI- 0.1087) was found to dominate the entire stretch of Nature trail 1, followed by Cannabis sativum (IVI- 20.8; SDI- 0.0108), Oxalis corniculata (IVI- 14.6; SDI- 0.0053) and Chenopodium album (IVI- 10.3; SDI- 0.0026). In case of basal area Nature Trail 2 was significantly higher (6.13 m(2)ha(-1)) than Nature Trail 1 (6.03 m(2)ha(-1)).