Primates bark-stripping trees in forest plantations – A review

Abstract

Primates bark-strip trees in forest plantations worldwide, producing large economic losses. The primate and tree species involved, the spatial and temporal patterns of this problem, the effectiveness of the methods used to mitigate damage and the causes of this behavior are not yet understood. I conducted a literature review of this topic, focusing on documents reporting primates bark-stripping trees in forest plantations and forests. The data set consisted of 51 documents of which 46 corresponded to bark-stripping of trees in forest plantations and five in managed forests. Thirteen non-human primate species have been recorded bark stripping trees of commercial value worldwide. Three of these, the chacma baboon (Papio ursinus), the black capuchin monkey (Sapajus nigritus) and Sykes´s monkey (Cercopithecus albogularis), are responsible for most of the damage reported in large scale plantations, affecting mostly pine (Pinus sp.) plantations in five African and two South American countries. With fewer reports, orangutans (Pongo pygmaeus) affect large scale Acacia mangium plantations in Indonesia, and yellow baboons (Papio cynocephalus) and vervets (Chlorocebus aethiops) pine plantations in Malawi and Zimbabwe respectively. The Barbary macaque (Macaca sylvanus) bark-strips Atlas cedars (Cedrus atlantica) in Moroccan forests. Eucalyptus sp. plantations, both small and large-scale, are less frequently affected by gorillas, two colobine monkeys, howler monkeys, capuchins, baboons and chimpanzees. Actions to mitigate this problem, including the massive killing of primates, had proven ineffective in the long term. Bark-stripping of pines tends to be more seasonal than that of Eucalyptus, and their damage of higher incidence and intensity. The most frequently cited hypothesis for why primates bark-strip trees in plantations is that they consume soft bark when or where their natural food is scarce. However, this hypothesis is not generally supported by empirical evidence. Eucalyptus bark may be sought after for its high sodium content. Pines are apparently bark-stripped to consume the sugary phloem during their growing season, when bark is presumably more easily peeled off. If this hypothesis were correct, a management method based on diversionary feeding could alleviate the damage produced by primates to coniferous trees of commercial value.