Behaviour 2019
Dynamic changes in social network cohesion in response to anthropogenic and natural disturbances
Gabriella E. C. Gall1, Julian C. Evans2, Matthew J. Silk 3, Chelsea Ortiz-Jimenez4, Jennnifer E. Smith1. 1Biology Department, Mills College, Oakland, California, United States; 2Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, , Switzerland; 3Centre for Ecology and Conservation, University of Exeter, Exeter, , United Kingdom; 4Department of Environmental Science and Policy, University of California, Davies, California, United States

Humans have altered nearly every habitat on earth, yet the degree to which anthropogenic disturbances relative to natural threats alter group dynamics in social animals remains poorly understood. Here we apply a social network framework to examine the potential for social resilience in California ground squirrels (Otospermophilus beecheyi). We examined changes in the assortativity and connectivity of affiliative networks (e.g., proximity maintenance, group foraging, greeting, and play behaviors) in response to disturbances by: humans, domestic dogs, or coyotes. Overall, juveniles were more socially-connected than adults. Although affiliation networks were generally more connected after than before disturbances, the directional effects of disturbances varied by disturbance types. Human presence reduced connectivity whereas dogs and coyotes had a neutral or slight positive effect. We also found consistent individual differences in social resilience to disturbances, particularly for adults, whereby some individuals were consistently more reactive than others. These findings suggest that even species living in an anthropogenic environment still continually adjust to human disturbances.