The effects of human-caused mortality on mammalian cooperative breeders: a synthesis.

Human-caused mortality can be pervasive and even highly selective for individuals in groups of cooperative breeders. Many studies of cooperative breeders, however, do not address human-caused mortality. Similarly, studies focused on the effects of human-caused mortality on wildlife populations often do not consider the ecology of cooperative breeders. We searched the literature and identified 58 studies where human-caused mortality affected a group characteristic, vital rate, or population state of a cooperative breeder. Of studies reporting population growth or decline, 80% reported a link between human-caused mortality and population declines in cooperative breeders. Such studies often did not identify the mechanism behind population declines, but 28% identified concurrent declines in adult survival and another 21% reported concurrent declines in recruitment or reproduction. There was little overlap between the cooperative breeding and human-caused mortality literatures, limiting our ability to accrue knowledge. Future work would be beneficial if it (i) identified the vital rate(s) causing population declines, (ii) leveraged management actions such as lethal removal to ask questions about the ecology of group-living in cooperative breeders, and (iii) used insights from cooperative breeding theory to inform management actions and conservation of group-living species.