Primate crop-raiding: A study of local perceptions in four villages in North Sumatra, Indonesia

Abstract

The main threat to the survival of primates in Sumatra is habitat destruction, but there is also an increasing problem of conflict with local people due to crop-raiding. This study characterizes the perceived impacts of primate crop-raiding in four villages in North Sumatra. Ninety-eight semi-structured interviews were conducted to collect data on (i) crop species, (ii) which vertebrates are thought to damage crops, (iii) the perceived extent to which each vertebrate species damages crops, and (iv) the preventive measures taken in the four villages. Farmers reported an average of 16 different crop species; 85.7% had rubber plantations. Crop-raiding by wildlife was reported by 94.9% of the interviewees as the single most important determinant of crop yields. Thirteen vertebrates were reported causing damage to cultivars; most important were squirrels, porcupines, pigs, deer, elephants and primates. However, primates were perceived as damaging crops differently from the other vertebrate species. Long-tailed macaques (Macaca fascicularis) and Thomas' leaf monkeys (Presbytis thomasi) were considered to be the most destructive cropraiders in all locations. Contrary to what was expected, only a small proportion of farmers complained about the Sumatran orangutan (Pongo abelii). The interviewees reported twenty different crop protection techniques. Shouting was the most common.