Date of Graduation

12-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Biology (PhD)

Degree Level

Graduate

Department

Biological Sciences

Advisor

Douglas James

Committee Member

Steven Stephenson

Second Committee Member

Ragupathy Kannan

Third Committee Member

John Willson

Keywords

Hornbill, Large-bodied Frugivores, Large-seeded Species, Seed Dispersal, Tropical Forests, Western Ghats

Abstract

Western Ghats, the mountain chain running along the west coast of India, is one of eight global hotspots of biodiversity and is particularly notable for its endemic flora and fauna. Yet only 10% of this land enjoys the protected status. Vast forested lands exist outside the protected network of national parks and wildlife sanctuaries in the form of reserve forests, community forests, and private lands. The present study sought to understand the role of such forests in the context of ecological system involving large-seeded tree species that depend on large-bodied avian frugivores for seed dispersal. I conducted a study over two and half years in Vazhachal Reserve Forest to collect information on the fruiting phenology of large-seeded tree species consumed by sympatric hornbills, the role that hornbills play in transporting the seeds of these trees to their nest sites, and rates of encounters with the large-bodied avian frugivores in these forests: Great Hornbill (Buceros bicornis) Linnaeus, (1758), Malabar Grey Hornbills (Ocyceros griseus) Latham, (1790) and Mountain Imperial Pigeons (Ducula badia) Raffles (1822). The analysis of fruiting phenology showed that lipid-rich fruits are generally available during the peak hot and dry season that coincides with nesting period of the Great Hornbill and the Malabar Grey hornbill. A significantly higher number of seedlings-saplings belonging to large-seeded tree species were documented in front of the hornbill nests compared to behind the nests, indicating that hornbills may be helping these species by removing their seeds from host-specific seed predators and fierce resource competition beneath their parent trees. Both hornbill species showed higher encounter rates than those recorded in a 2008 survey from Vazhachal Reserve Forests. Vazhachal Reserve Forest juxtaposes with Parambikulam and Anamalai Tiger Reserves and potentially acts as a link between these habitats for long-ranging species such as the Great Hornbill and also provides food resources outside the protected area network. The data on fruiting collected during this study can be added to that collected by the hornbill nest monitoring program currently run by Kerala Forest Department and tribal community members to inform the design and implementation of local conservation policies and lay the groundwork for future long-term studies.

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