Anthropogenic mortality in mammals increases with the human footprint

Over the Earth's terrestrial surface, wildlife species are adversely affected by an increasing number of anthropogenic impacts to the landscape, collectively termed the human footprint. However, there is limited understanding of how the human footprint influences cause-specific mortality in wildlife. We conducted a synthesis of cause-specific mortality of North American terrestrial mammals, compiling 247 studies that as a group determined the cause of death of 6607 adult mammals among 19,910 individuals monitored. Species lifespan as well as the interaction between lifespan and the human footprint were positively associated with the proportion of mortality attributed to anthropogenic sources. Our results indicate that anthropogenic mortality in mammals increases with increasing human-associated impacts on the landscape, and that longer-lived species are affected more than their shorter-lived counterparts. This pattern likely accounts for the extirpation of longer-lived, larger-bodied mammals from many human-dominated areas. We also found that as the human footprint increased in magnitude, harvest mortality declined while vehicle mortality increased. These shifts in mortality can have substantial implications for understanding wildlife population dynamics and managing wildlife populations across landscapes impacted by anthropogenic activities.