Human interference with wildlife surveys 803


FIG. 1 Locations of camera traps installed in bridge underpasses, and of protected areas, in the Osa Peninsula, Costa Rica. (Readers of the printed journal are referred to the online article for a colour version of this figure.)


Gates, 2012; Denneboom et al., 2021; Monge-Velázquez & Saenz, 2022). Studies that have included bridges have been concentrated in North America (Warnock-Juteau et al., 2022) and Australia (Goldingay et al., 2022). The Osa Peninsula is hometo the largest remnant tract of


Pacific lowland wet forest inMesoamerica (Holdridge, 1967) and contains four protected areas (Fig. 1;Weissenhofer et al., 2001). The region is traversed by a network of unpaved roads and two paved highways: National Route 245 (7–8 m wide and stretching 77 km from Puerto Jimenez to Chacarita, overpassing 15 substantial rivers) and Inter-American Highway 2 (7–10 m wide and stretching 57 km from


Sierpe to Rio Claro, overpassing 13 substantial rivers). A region-wide camera-trap study in 2018 verified the pres- ence of wide-ranging megafauna species and documented 23 wild terrestrial mammal species (Vargas et al., 2022). The wildlife community is recovering throughout the region, with many species that were once restricted to Corcovado National Park now widespread across the landscape (Carrillo et al., 2000; Vargas et al., 2022). This confirms the presence of a mammal community that could utilize and benefit from safe road crossings for further dispersal. We installed single camera-trap monitoring stations (Bushnell Trophy Cam HD Aggressor, Bushnell, USA; set


PLATE 1 Camera trapping with theft protection. (a) A camera trap from the study with a metal case, lock and laminated sign. (b) Close-up of the sign in (a), which explains the project in Spanish and English, with visual representations and a contact number (blacked out).


Oryx, 2024, 58(6), 802–805 © The Author(s), 2025. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605324000097


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