Quantifying the road‐effect zone for a critically endangered primate

The global road network is expanding at an unprecedented rate, threatening the persistence of many species. Yet, even for most endangered wildlife, crucial information on distance up to which roads impact species abundance lacking. Here we use ecological threshold analysis quantify road-effect zone (REZ) critically western chimpanzee (Pan troglodytes verus). We found: (1) REZ extends 5.4 km (95% CI [4.9–5.8 km]) from minor and 17.2 [15.8–18.6]) major roads, latter being more than three times wider a previous estimate average mammals; (2) only 4.3% chimpanzees’ range not impacted by existing roads. These findings reveal high sensitivity susceptibility nonhuman primates across West Africa, region undergoing rapid development, can inform implementation effective guidelines mitigate impacts.