Effects of tourism exposure on habitat use and foraging support selection by Indri ( Indri indri ) in Eastern Madagascar

Abstract Background : As tourism interest in Madagascar's unique biodiversity continues to grow, understanding its potential impacts on wildlife behavior and habitat use becomes increasingly vital. Specifically, the effects of tourism exposure on the habitat utilization and foraging support selection of the critically endangered lemur Indri ( Indri indri ) remain underexplored. Objectives : This study aims to examine how different levels of tourism exposure influence the foraging preferences and support use of Indri indri populations in both a restored National Park and a previously degraded Forest Station of Analamazaotra. Methods : By using scan sampling methods, we observed six Indri groups during 117 h and 10 min of fieldwork. These groups were categorized into three supergroups based on their level of tourism exposure: non-tourist (NT), which were completely isolated from tourist presence; tourist (T), which are aware of and may interact with tourists; and intermediate (INT), which might hear tourists but lacked direct visual contact. We recorded the frequency of foraging activities, along with the diameter at breast height (DBH) and height of supports used during foraging. We obtained a total of 816 scan samples with 359 foraging cases. Results : Indri primarily foraged on trees rather than shrubs. Groups with limited or auditory-only exposure to tourists (INT) used supports with larger DBH, indicating reduced stress and more natural foraging behavior. Conversely, NT and T groups foraged at lower heights, possibly due to habitat degradation. Variations in support height appeared linked to habitat quality, disturbance levels, and behavioral adaptations, with some groups in degraded areas adjusting their foraging strategies to resource scarcity. Conclusions : This research highlights the importance of integrating behavioral studies with habitat management to support Indri populations amid increasing tourism pressures. It emphasizes the need for further investigation into behavioral responses to auditory and visual disturbances and their ecological implications, ensuring the conservation of this critically endangered species.