Assessing the Human Monkey Conflict in Bulathsinhala Divisional Secretariat in Kalutara District, Sri Lanka

Abstract

In Sri Lanka, Human Monkey Conflict (HMC) is a growing issue mainly due to habitat loss caused by urbanization, agricultural expansion and human population. This study assessed the level of impact on humans and the aggressiveness of precautionary actions taken by households in eight Grama Niladari Divisions (GND) in Bulathsinhala Divisional Secretariat (BDS). These GND were selected based on existing literature and records from the BDS office, related to HMC. Accordingly, Ihala Naragala, Bulathsinhala-South, and Kongasthenna were recorded as not-affected divisions; Polegoda-West, Molkawa, Pahala Kudaligama, Ihala Naragala-South, and Delmella GND as affected divisions. The current situation of HMC was assessed by conducting semi-structured interviews with 100 households across those GND. It underlines the presence of two species, Toque macaque (Macaca sinica) and Purple-faced langur (Semnopithecus vetulus), while Toque macaque is the most dominant species which are causing substantial damage to crop and infrastructure and translates into economic losses. The impact level of the HMC was identified as highly affected, moderately affected, less affected, and not affected based on three criteria: the frequency of monkey visits, monthly economic loss, and negative impacts on properties and lives, such as crop, food, and material loss, attack household, infrastructure and roof damage, and physical injuries to humans. The precautionary actions were categorized based on their aggressiveness: extremely aggressive (resulting in monkey deaths), very aggressive (causing severe physical injuries), moderately aggressive (causing minor physical injuries), and less aggressive (causing no physical injuries) chasing monkeys away. According to the qualitative analysis, monkeys have been visiting Kongasthenna and Bulathsinhala-South occasionally and identified as non-affected GND. Monkeys visited less affected GND such as Delmella, Ihala Naragala, and Molkawa monthly. Polegoda-west was identified as moderately affected and 30% of the interviewees experienced daily visits, 60% experienced weekly visits by monkeys and 75% households had an economic loss between Rs.5,000.00-10,000.00. The highly affected GND were Pahala Kudaligama and Ihala Naragala-South with 70% and 25% daily visits respectively while a cumulative percentage of 60% households experienced an economic loss over Rs.10,000.00. Extreme and very aggressive precautionary actions could be observed in highly and moderately affected areas. As the conflict intensifies, residents adopt more extreme measures to protect their belongings from monkeys. As mitigation measures for HMC in BDS, the use of non-lethal deterrents such as high frequency noise and visual deterrents, community awareness programs, crop alterations and habitat management plans can be proposed.

Keywords: Human-monkey Conflict, Toque macaque, Purple-faced langur, Affected levels, Aggressive levels