Linear infrastructure and associated wildlife accidents create an ecological trap for an apex predator and scavenger

Abstract

Animals may fall into an 'ecological trap' when they select seemingly attractive habitats at the expense of their fitness. This maladaptive behavior is often the result of rapid, human-induced changes in their natal environment, such as the construction of energy and transportation infrastructure. We tested the ecological trap hypothesis regarding human-created linear infrastructure on a widely distributed apex predator and scavenger-the Golden Eagle (Aquila chrysaetos), whose range spans the entire Northern Hemisphere. Roads and railways offer novel and attractive feeding opportunities through traffic-induced mortality of other species, while powerline areas provide perching or nesting sites and scavenging opportunities from electrocuted or collision-killed birds. These conditions may have negative demographic consequences for eagles if these apparent opportunities turn into traps. Using step selection functions, we analyzed habitat selection of 74 GPS-tracked Golden Eagles (37 adults and 37 immatures) during eleven years in Fennoscandia. To assess habitat attractiveness, we used wildlife traffic accident statistics for dominant wild species, and to evaluate demographic consequences, we used mortality data from the GPS-tagged eagles. Our analysis revealed that eagles selected linear features such as roads, railways and powerlines at both the population and individual levels. Both adult and immature eagles consistently selected these features, and the strength of selection for linear features increased with age in immature eagles. The linear features however had 5.5 times higher mortality risk for eagles than other selected habitats indicating the presence of an ecological trap. We discuss the implications of these findings for the conservation and population ecology of apex predators and scavengers, as well as their potential demographic consequences. To mitigate this issue, we urgently recommend the removal of carcasses from roads and tracks to prevent ecological traps for raptors and scavenger species worldwide. Additionally, we advocate for the development of methods and strategies to reduce wildlife traffic accidents.

Keywords: Animal behavior; Animal ecology; Animal movement; Fitness; HIREC; Habitat selection; Integrated step selection function; Maladaptive behavior; Wildlife traffic accidents.