Fruit Removal, Seed Dispersal and Demography of Emblica officinalis at Rajaji National Park, Uttaranchal

Abstract

Plant-frugivore interactions determine the structure and composition of plant and frugivore communities and consequently the understanding of these interactions may help in defining the management protocol for the conservation of these systems (Howe 1993). E.officinalis fruit are an important non-timber forest produce from Indian deciduous forests. In this study I have looked at fruit removal and seed dispersal patterns of E. officinalis in the context of its use by humans. Fruit removal patterns were followed for 19 E. officinalis trees with a range of fruit crops (from 73 ± 59 X 103 fruit to less than 100 fruit) at Dhaulkand, Rajaji NP. 11 of these trees were monitored to ensure that there was no human removal of the fruit. For each tree, all fruit on the ground in the fruit fall area and all fruit on 5 -7 marked branches were counted thrice every ten days in 12-hour intervals, till less than 5% of the initial number of fruits remained on the .marked branches, to arrive at nocturnal and diurnal removal patterns for fruit. Factors affecting fruit persistence (number of days fruit persisted. on the marked branches) were extraction of fruit by people and fruit crop size. In the fruit-fall area, factors affecting nocturnal and diurnal fruit removal rates were clustering of fruiting trees and human induced factors. A range of direct and indirect methods - tree watches, track plots and camera trapping were used to determine the identity of the fruit removers and to observe the mode of fruit handling by these removers. Langur (Semnopithecus entellus), ungulates such as chital (Axis axis) and barking deer (Muntiacus muntjac) were observed feeding on E. officinalis fruit. There was also evidence that the gerbil, Tatera indica, scatter hoards the fruit. Retention In ungulate rumens reduced germination success of E. officinalis seeds. Demography of E. officinalis and regeneration status of woody plant species at Rajaji was assessed along 6 one Ian transects' across a gradient of human use intensity, 3 each in hill and plain mixed forests. The E. officinalis population at Rajaji was found to have very few trees below 30 cm GBH. E. officinalis seedlings were found only in areas almost completely free from human use. Regeneration for tree species at Rajaji was dominated by species that are not lopped for fodder.