Female philopatry and unsuccessful male dispersal of a top predator in a human-modified landscape revealed by relatedness analysis

Abstract

Abstract Habitat loss and fragmentation threaten population persistence because they affect the individuals’ ability to disperse between remaining habitat patches and reduce areas of refuge for populations. In cougars (Puma concolor), males are predominantly dispersers while females tend to be philopatric. To examine cougar philopatry and dispersal ability in a human-dominated landscape in Brazil, we performed relatedness and spatial autocorrelation analyses based on genetic samples of cougars inhabiting forest fragments within a human-modified matrix, a continuous forest, and a pool of road-killed individuals. Our expectation was that females would be more related to each other and show a more positive autocorrelation than males in areas with less human disturbance because male dispersal would not be constrained. We found similarly high relatedness and a positive spatial autocorrelation at the shortest spatial scale (0-100 km) for both males and females from the forest fragments within a human-modified matrix. We also detected higher male:female ratio from roadkills, likely due to males’ higher tendency to disperse. Our results confirm female philopatry in the forest fragments. However, high relatedness and positive autocorrelation also observed for males in these fragments suggest male kin clustering, which could be a result of unsuccessful dispersal. Cougar unsuccessful dispersal has already been reported in North America in response to human-altered landscapes, but here we present the first evidence of this process in a South American cougar population. Further research is warranted to assess the specific causes of male unsuccessful dispersal and how it can affect species persistence in human-dominated landscapes.