Electrocution from power infrastructure threatens many primate species, yet knowledge of effective evidence-based mitigation strategies is limited. Mitigation planning requires an understanding of the spatial distribution of electrocutions to prioritize high-risk areas. In Diani, a coastal Kenyan town, electrocution is an important cause of death for five primate species. In this study we aim to describe the spatial patterns of electrocutions and electric shock incidents (collectively referred to as electrocutions hereafter) and identify electrocution hotspots to guide an effective primate conservation approach in Diani. Colobus Conservation, a not-for-profit organization, has recorded electrocutions and annual primate census data since 1998. We georeferenced 329 electrocution data points and analyzed them using QGIS. We identified and compared hotspots across species, seasons, and time using kernel density estimation and Getis-Ord-Gi*. We employed spatial regression models to test whether primate population density and power line density predicted the location of electrocution hotspots. Electrocutions occurred in hotspots that showed little variation in location between species and seasons. The limited variation in hotspot location over time likely occurred as a result of new building development in Diani and variability in primate detection rates by community members. Primate density and power line density were significant predictors of electrocution density for Angolan black-and-white colobus (Colobus angolensis palliatus) and Sykes monkeys (Cercopithecus mitis albogularis), but the relationship was weak, suggesting the presence of additional risk factors. This study provides a framework for systematic spatial prioritization of power lines that can be used to reduce primate electrocutions in Diani, and can be adopted in other areas of the world where primates are at risk from electrocution.

As road infrastructure networks rapidly expand globally, especially in the tropics, previously continuous habitats are being fragmented, resulting in more frequent wildlife–vehicle collisions (WVC). Primates are widespread throughout many sub-/tropical countries, and as their habitats are fragmented, they are increasingly at risk of WVC. We created the Global Primate Roadkill Database (GPRD), the largest available standardized database of primate roadkill incidents. We obtained data from published papers, un-published and citizen science databases, anecdotal reports, news reports, and social media posts. Here, we describe the collection methods for the GPRD and present the most up-to-date version of the database in full. For each primate roadkill incident, we recorded the species killed, the exact location, and the year and month the roadkill was observed. At the time of publication, the GPRD includes 2862 individual primate roadkill records from 41 countries. As primates range in more than twice as many countries, the absence of data from these countries is not necessarily indicative of a lack of primate vehicular collisions. Given the value of these data for addressing both local and global research questions, we encourage conservationists and citizen scientists to contribute to the GPRD so that, together, we can better understand the impact road infrastructure has on primates and evaluate measures which may help mitigate risk-prone areas or species.

For primates, canopy bridges can reduce the road barrier effect. Yet little information exists to predict species bridge use. We examined bridge use across a 9 km suburban road in Diani, Kenya, in three survey years ( N _bridges : 21 = 2004, 27 = 2011, 29 = 2020) by four sympatric species of monkeys. The asphalt road is 6 m wide with a 50 km/h speed limit. Roadside observers recorded ground ( ) and bridge ( ) crossings, crossing direction, and traffic volume. Colobus ( Colobus angolensis palliatus ), Sykes’ monkeys ( Cercopithecus mitis albogularis ), and vervets ( Chlorocebus pygerythrus hilgerti ) used the bridges while baboons ( Papio cynocephalus cynocephalus ) rarely did. Crossing rates (Sykes’>vervet>colobus>baboon) did not fit our predictions based on species’ attributes of stratum preference (arboreal>terrestrial) or body mass (small>large), while the interaction between these attributes was more informative. Crossings were bidirectional. Colobus crossed bridges during higher traffic volumes than on the ground, whereas we found the opposite for vervets. Sykes’ monkeys crossed at similar traffic volumes on the ground and bridges. The mean annual bridge cost was USD 157, deriving a cost per crossing as < USD 0.10, though it undervalues the savings in ecosystem services, tourism benefits, and contributions to protecting colobus, a vulnerable species. While we consider this highly economical, funders and road engineers will ultimately determine if it is so.