Northern pigtailed macaques rely on old growth plantations to offset low fruit availability in a degraded forest fragment

Abstract

Space-use and foraging strategies are important facets to consider in regard to the ecology and conservation of primates. For this study, we documented movement, ranging, and foraging patterns of northern pigtailed macaques (Macaca leonina) for 14 months in a degraded habitat with old growth Acacia and Eucalyptus plantations at the Sakaerat Biosphere Reserve in northeastern Thailand. We used hidden Markov models and characteristic hull polygons to analyze these patterns in regard to fruit availability. Macaques' home range (HR) was 599 ha and spanned through a natural dry-evergreen forest (DEF), and plantation forest. Our results showed that active foraging increased with higher fruit availability in DEF. Macaques changed to a less continuous behavioral state during periods of lower fruit availability in DEF, repeatedly moving from foraging to transiting behavior, while extending their HR further into plantation forest and surrounding edge areas. Concomitantly, macaques shifted their diet from fleshy to dry fruit such as the introduced Acacia species. Our results showed that the diet and movement ecology adaptations of northern pigtailed macaques were largely dependent on availability of native fruits, and reflected a "high-cost, high-yield" foraging strategy when fresh food was scarce and dry fruit was available in plantation forest. Conversely, wild-feeding northern pigtailed macaque populations inhabiting pristine habitat approached a "low-cost, low-yield" foraging strategy. Our results outline the effects of habitat degradation on foraging strategies and show how a flexible species can cope with its nutritional requirements. K E Y W O R D Sforaging strategies, fruit availability, habitat degradation, hidden Markov models, ranging patterns

Oil palm cultivation critically affects sociality in a threatened Malaysian primate

“…Our results confirm previous research, which suggests that oil palm plantations function as foraging and feeding grounds for macaques 40 , 41 , 59 . Their motivation to range within these monocultures despite increased predation risk, indicated by rates of flight responses five to ten times higher compared to those observed in the forest, likely lies in the high abundance of food.…”

“…Their motivation to range within these monocultures despite increased predation risk, indicated by rates of flight responses five to ten times higher compared to those observed in the forest, likely lies in the high abundance of food. Previous studies suggested more frequent plantation visits and extended plantation ranges during periods of lower fruit availability in the forest 45 , 59 . Further, regular plantation visits may be triggered by the high nutritional value of available food sources, as the macaques not only feed on palm fruits but also consume a high number of plantation rats 41 .…”

Oil Palm Cultivation Critically Affects Sociality in an Endangered Malaysian Primate

“…Our results con rm previous studies, which suggest that oil palm plantations function as foraging grounds for macaques 36,37,47 . Their motivation to range within these monocultures despite increased predation risk, indicated by rates of ight responses ve to ten times higher compared to those observed in the forest, likely lies in the broad abundance of food.…”

“…Their motivation to range within these monocultures despite increased predation risk, indicated by rates of ight responses ve to ten times higher compared to those observed in the forest, likely lies in the broad abundance of food. Previous studies suggested more frequent plantation visits and extended plantation ranges during periods of lower fruit availability in the forest 47,48 . Further, regular plantation visits may be triggered by the high nutritional value of available food sources, as the macaques do not only feed on palm fruits, but also consume a high number of plantation rats 37 .…”

Ranging patterns of Japanese macaques in the coniferous forest of Yakushima: Home range shift and travel rate

“…In montane habitats, the environment changes gradually along an elevational gradient, and many species exhibit altitudinal seasonal migration (Buij, Wich, Lubis, & Sterck, 2002; Green, Boruff, Niyigaba, Ndikubwimana, & Grueter, 2020; Li et al, 2008; Tan, Guo, & Li, 2007). Human disturbance may also bring about a small‐scale spatial heterogeneity that enables seasonal habitat shift for primates (Gazagne et al, 2020; Ruppert, Holzner, See, Gisbrecht, & Beck, 2018). Quantitative assessment of how primates utilize different food resources in these different habitats is necessary to explore the factors driving habitat shift.…”