Shifts in the demographics and behavior of bearded pigs (Sus barbatus) across a land‐use gradient

Abstract

Beyond broad‐scale investigations of species diversity and abundance, there is little information on how land conversion in the tropics is affecting the behavior and demographics of surviving species. To fill these knowledge gaps, we explored the effects of land‐use change on the ecologically important and threatened bearded pig (Sus barbatus) over seven years in Borneo. Random placement of camera traps across a land‐use gradient of primary forest, logged forest, and oil palm plantations (32,542 trap nights) resulted in 2,303 independent capture events. Land‐use was associated with changes in the age structure and activity patterns of photographed individuals, alongside large changes in abundance shown previously. The proportion of adults recorded declined from 92% in primary forests to 76% in logged forests, and 67% in plantations, likely indicating increased fecundity in secondary forests. Activity level (capture rate) did not vary, but activity patterns changed markedly, from diurnal in primary forests, crepuscular in logged forests, to nocturnal in plantations. These changes corresponded with avoidance of diurnal human activity and may also protect bearded pigs from increased thermal stress in warmer degraded forests. The percentage of adult captures that were groups rather than individuals increased five‐fold from primary forests (4%) to logged forests (20%), possibly due to increased mating or in response to perceived threats from indirect human disturbance. We recommend further investigation of the demographic and behavioral effects of land‐use change on keystone species as altered population structure, activity patterns, and social behavior may have knock‐on effects for entire ecosystems.

A Research Agenda for Microclimate Ecology in Human-Modified Tropical Forests

“…Related to this, we need to understand what physiological and behavioral strategies species adopt to cope with or evade unfavorable microclimates. For instance, mobile species might shift from diurnal to nocturnal activity to escape warmer temperatures (Davison et al, 2019;Levy et al, 2019), while sessile organisms such as plants can thermoregulate by increasing transpiration and adjusting leaf angles (Fauset et al, 2017). Alternatively, some species may be able to rapidly acclimate and/or adapt to novel microclimates, as was recently shown for a poison frog in Costa Rica that exhibits higher preferred body temperatures in forests that have been logged (Rivera-Ordonez et al, 2019).…”

Transformation and endurance of Indigenous hunting: Kadazandusun-Murut bearded pig hunting practices amidst oil palm expansion and urbanization in Sabah, Malaysia

“…Recent ecological evidence from Sabah suggests substantial rates of bearded pig crop raiding in oil palm plantations (Love et al 2018, Davison et al 2019, which was widely reported amongst our respondent pool as well. We therefore hypothesize that bearded pigs in many parts of Sabah are employing a "high risk, high reward" strategy of feeding on cross-border oil palm fruit subsidies, providing access to high-fat food resources but also elevating risk due to human hunting in oil palm plantations, potentially causing elevated flight responses in pigs.…”

“…increasing the proportion of young pigs in plantations), and changing activity patterns (e.g. shifting pigs to nocturnal activity patterns in plantations) (Love et al 2018, Davison et al 2019. Research has also shown how bearded pigs benefit from crop-raiding in oil palm plantations (Love et al 2018, Davison et al 2019, and has hypothesized that this behavior could potentially increase their populations near oil palm plantations (Luskin et al 2017, Love et al 2018, Davison et al 2019.…”

Transformation and endurance of Indigenous hunting: Kadazandusun‐Murut bearded pig hunting practices amidst oil palm expansion and urbanization in Sabah, Malaysia

“…increasing the proportion of young pigs in plantations) and changing activity patterns (e.g. shifting pigs to nocturnal activity patterns in plantations) (Davison et al, 2019;Love et al, 2018). Bearded pigs also receive food subsidies from crop-raiding within oil palm plantations (Davison et al, 2019;Love et al, 2018), and it has been hypothesized that this behaviour could potentially increase wild pig populations near oil palm (Davison et al, 2019;Love et al, 2018;Luskin, Brashares, et al, 2017).…”