Assessment of crop and property damage caused by Semnopithecus vetulus nestor (Bennett, 1833) (Mammalia: Primates: Cercopithecidae) in Gampaha District, Sri Lanka

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Sunil Wijethilaka
Lakshani S. Weerasekara
Saumya Bandara
Kithsiri B. Ranawana


In earlier times, human-monkey interactions were not a severe problem in Sri Lanka, but has recently intensified as a result of habitat fragmentation and urbanization.  Due to these changes, Semnopithecus vetulus nestor has been listed among the 25 most Endangered primates.  The objective of our study was to evaluate the intensity of human-S.v. nestor negative interaction by identifying the crop and property damages in villages bordering Danawkanda Forest (7.001N & 80.049E), Gampaha, Sri Lanka.  We collected data using structured questionnaires interviewing households (N= 80) bordering the Danawkanda Forest from August 2014 to January 2015.  Households were most affected by damage to fruits, leaves, and buds of commercially important trees (93%), followed by damage to roof tiles (76%), and frightful confrontations with the monkeys (43%).  Average monthly loss per household from crop and property damage was estimated at between (Sri Lankan Rupees) LKR 2,700 and LKR 1,500.  Lighting firecrackers was the most common method used by the residents (99%) to deter monkeys, where as electrified barriers were rarely used (4%).  Households in close proximity to Danawkanda Forest experienced a considerable loss to their monthly income due to crop and property damage, compared to households further away.  As an alternative, residents now grow ornamental plants and short trees, eliminating the structures that attract and facilitate damage by S.v. nestor.  Awareness and active participation of residents, authorized government, and non-governmental organizations are needed to manage unplanned construction and agriculture plot extensions into the forest.  These two factors trigger the human-wildlife negative interactions in general and are not limited just to monkeys.

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