A trans‐island canopy bridge network 189


TABLE 1 List of individual vertebrate carcasses recorded on roads across Langkawi Island, Malaysia (Fig. 1), during October 2021–January 2022.


Taxon


Common long-tailed macaque Macaca fascicularis fascicularis Southeast Asian water monitor Varanus salvator macromaculatus Clouded monitor Varanus nebulosus


Tarutao Island dusky langur Trachypithecus obscurus carbo Grey-bellied squirrel Callosciurus caniceps Malaysian eared nightjar Lyncornis temminckii Masked palm civet Paguma larvata Greater slow loris Nycticebus coucang


Oriental pied hornbill Anthracoceros albirostris Reticulated python Malayopython reticulatus Total


1EN, Endangered; NT, Near Threatened; LC, Least Concern.


than data on herpetofauna roadkill collected during 2017– 2018, which recorded 131 incidents (Ayob et al., 2020). During October 2021–January 2022 we assessed verte-


brate roadkill, focusing on primates. We scanned selected transects twice per day for 15 days each month. The com- bined length of all transects scanned (without repetition) was 35.17 km. We selected these transects from across the c. 251 km-long road network of Langkawi Island (excluding roads within urban housing areas; Fig. 1). A transect here refers to a specific section of tarmac road that is part of the main road network. We scanned these transects from a moving vehicle at a speed of c. 35 km/h. The purpose of these scans was to search for animal carcasses on the road or roadside. The selection of transects was informed by per- sonal communication with knowledgeable local people (community naturalists and guides working around the is- land), who provided insight regarding where primates were known to occur at roadsides. We consulted with eight peo- ple prior to and whilst conducting the transect scans. Assuming that a higher density of primates along roadsides could result in a proportionally higher occurrence of road crossings and subsequent roadkill, this information guided the identification and prioritization of road sections where we conducted transect scans. We did not add further trans- ects to the study after the initiation of our roadkill assess- ment once we ascertained there were no other road sections where primates frequently crossed or occurred at roadsides. We identified and recorded the locations of ver- tebrate carcasses found on these transects and also oppor- tunistically elsewhere on the island. During the same period, we assessed and documented


the activity of diurnal primates (M. fascicularis fascicularis and T. obscurus carbo) at roadsides along the study trans- ects. We used a group scan sampling method (Altmann, 1974)of 2-min intervals during periods when groups were present at roadsides at any time between 8.30 and 17.30 on


observation days. The behavioural categories of scanned in- dividuals recorded were feeding (on vegetation, provisions and roadside waste), social activities (grooming and play- ing) and resting (sitting and observing). We also noted any instances of road crossing (fully or partially), road vigi- lance (hesitancy/observance) and interspecies activity (tol- erance of other primate species). We collected 160 hof behavioural observations. We recorded 65 individual animal carcasses across


Langkawi Island during the 4 months, with 38% belonging to M. fascicularis fascicularis (Table 1). We also recorded in- dividual roadkills of T. obscurus carbo (8%) and N. coucang (2%). The highest concentrations of roadkill were at road sections Jalan Teluk Datai, Jalan Teluk Yu, Jalan Pantai Kok and Jalan Ayer Hangat (Fig. 1). At each of these sites, primates forage regularly along the roadside at ground level or in the canopy. Along these four roads, M. fascicularis fascicularis spent a


mean of 4.25 h per day at ground level. Most of this time (43%) they spent feeding on roadside verge grass (21%), waste disposed at roadsides (13%) and food provided by local people and tourists (9%). The remainder of their time they spent resting (36%) and engaging in social activ- ities (21%). They frequently crossed from one roadside to the other, either to join other group members or whilst playing. Trachypithecus obscurus carbo spent a mean of 55 min per day observing road activity from the treetops before retreat- ing into the forest. Their presence at roadsides was limited and inconsistent, and we could not derive comprehensive information about their roadside behaviour through scan sampling. During the study period we recorded eight langur crossing events, six of which were at Jalan Teluk Datai. Individuals descended to the ground and quickly crossed the road without checking for vehicles. We did not observe feeding behaviour by T. obscurus carbo at roadsides, but we recorded occasional grooming between group members.


Oryx, 2024, 58(2), 187–191 © The Author(s), 2023. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605323001333


Order/Class Primates


Reptilia Reptilia Primates Rodentia Aves


Carnivora Primates Aves


Reptilia


IUCN Red List status1


EN LC NT EN LC LC LC EN LC LC


Number of individuals (% of total)


25 (38.5) 16 (24.6) 7 (10.8) 5 (7.7) 5 (7.7) 2 (3.1) 2 (3.1) 1 (1.5) 1 (1.5) 1 (1.5)


65 (100)


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