Giraffe (Giraffa camelopardalis) social networks in areas of contrasting human activity and lion density

Abstract

The adaptive value of close social bonds and social networks has been demonstrated in a variety of vertebrate taxa. While the effect of predators on populations is well established, disturbance by humans is increasingly being identified as affecting the behaviour and reproductive success of animals and can have significant impacts on their survival. We used a concurrent analysis of two adjacent giraffe Giraffa camelopardalis populations in Kenya to determine whether human activities and high predation affected their social networks. One study site was a premier tourist destination with a high volume of human activity in the form of tourist traffic and lodge infrastructure, alongside a high density of lions which preferentially prey on giraffe calves; the other was a private wildlife conservancy with minimal human activity and no lion population. Giraffes in both networks showed preferred associations and avoidances of other individuals, which were independent of space use. Bond strength was lower in the population exposed to high levels of human activity and lions, and the network had lower density and clustering, and shorter path lengths, suggesting that it was more fragmented. We suggest that human activity and predator density may influence the patterns of social interactions in giraffes and highlight the importance of understanding the impact of tourism and management on the survival and success of wild animal populations.

Proximity to humans affects local social structure in a giraffe metapopulation

“…Hyenas living in areas of a national park with higher levels of human activity had less dense social networks, indicating animals interacted less with other clan members (Belton et al., 2018). Giraffes in a population with high levels of tourism and a high density of lions appeared to have weaker associations and more exclusive relationships than in a population without lions and few tourists (Muller et al., 2019). The results of that study, while remaining unclear due to a lack of statistical support, do align with our theory‐driven prediction, and our statistically significant findings, that disturbances can disrupt social structure.…”

“…Disruption to social systems also may be a contributing factor in population declines, but, to date, anthropogenic effects on social structure of giraffes remain unclear. One recent study by Muller, Cuthill, and Harris (2019) reported differences in network metrics across two separated, small, enclosed populations of Rothschild's giraffes in Kenya.…”

“…Disruption to social systems also may be a contributing factor in population declines, but, to date, anthropogenic effects on social structure of giraffes remain unclear. One recent study by Muller, Cuthill, and Harris (2019) reported differences in network metrics across two separated, small, enclosed populations of Rothschild's giraffes in Kenya. They found that relationships were weaker and more exclusive in a population inhabiting an area with a high volume of tourists and lions, compared to another population inhabiting an area with no lions and a low volume of tourists.…”

“…However, Muller et al. (2019) did not statistically compare the network characteristics of the two populations, and the effects of natural predation and human disturbance from tourism could not be discriminated due to the lack of replication beyond the two populations. In our study area, overlapping (i.e.…”

Simulated poaching affects global connectivity and efficiency in social networks of African savanna elephants - an exemplar of how human disturbance impacts group-living species

“…Although our focus was on improving the understanding of elephant social behavior in areas where poaching is an ongoing threat, our work may be of use to translocation practitioners working with other vulnerable species (Mengak, 2018; Muller et al, 2019). In the past, translocation specialists put their efforts into the optimization of the demographic (Miller et al, 1999) and genetic (Weeks et al, 2011) properties of target populations, as well as attributes of habitats intended for translocation (McCoy et al, 2014).…”