Assessment of Food Plant Species of Hoolock Gibbons: Distribution and Utilization Patterns in the Marat Longri–Patradisa–Longnit Forest Complex, Assam, North-East India

Abstract

The Hoolock Gibbon (Hoolock hoolock) is the only ape species found in India and plays an important role in maintaining forest ecosystems, apart from being an indicator of forest health. Knowledge of its feeding ecology is imperative in formulating effective conservation strategies, particularly in fragmented habitats. Presently, this study deals with the seasonal feeding ecology of Hoolock Gibbons in the Marat Longri–Patradisa–Longnit Forest Complex, Karbi Anglong, Assam. A survey was conducted from September 2023 to August 2024. Data were collected through focal animal sampling methods. Altogether 34 food plant species from 17 families were recorded. Fruits were found as the most frequently consumed plant part (67.65%), followed by leaves (47.06%), seeds (17.65%), and flowers (17.65%), and a minimum use of bark (2.94%). Among vegetation types, semi-evergreen forests supported the highest proportion of food species (35.29%), followed by moist deciduous (29.41%), evergreen (17.65%), and deciduous (17.65%) types. The availability of food plants shows seasonal variation, with the greatest diversity of consumable species during winter (47.06%) and monsoon (44.12%), while only 2.94% were available year-round. Height distribution analysis showed a preference for mid- to upper-canopy trees between 21–28.9 m, with 38.24% of the species. The Anacardiaceae (14.71%) and Moraceae (11.76%) families were the most represented; emphasize their ecological importance in the diet of the gibbon. These results show that this species depends on diverse forest types as well as tall canopy trees and stress the urgent need for habitat protection, restoration, and preservation of key food plant species for the long-term survival of Hoolock Gibbons in Northeast India.