Social networks: a tool for assessing the impact of perturbations on wildlife behaviour and implications for pathogen transmission

Abstract

Wildlife are increasingly subject to perturbations, which can impact pathogen transmission and lead to disease emergence. While a myriad of factors influence disease dynamics in wildlife, behaviour is emerging as a major influence. In this review, we examine how perturbations alter the behaviour of individuals and how, in turn, disease transmission may be impacted, with a focus on the use of network models as a powerful tool. There are emerging hypotheses as to how networks respond to different types of perturbations. The broad effects of perturbations make predicting potential outcomes and identifying mitigation opportunities for disease emergence critical; yet, the current paucity of data makes identification of underlying trends difficult. Social network analysis facilitates a mechanistic approach to how perturbation-induced behavioural changes result in shifts in pathogen transmission. However, the field is still developing, and future work should strive to address current deficits. There is particular need for empirical data to support modelling predictions and increased inclusion of pathogen monitoring in network studies.

Impacts of human disturbance in marine mammals: Do behavioral changes translate to disease consequences? Full methods and Analysis

“…Contact networks provide a versatile and intuitive tool to examine how behavioral changes induced by environmental perturbations can shift disease dynamics [9]. Contact networks are one of the only tools that allow for researchers to incorporate the heterogeneity of individual contacts, and the potential changes to them.…”

“…Contact networks are one of the only tools that allow for researchers to incorporate the heterogeneity of individual contacts, and the potential changes to them. Examples of the impact of environmental perturbations on disease spread that have been successfully modeled using contact networks include (as discussed in [9]): simulations of potential pathogen spread through translocated tortoise [131] and guppy [132] populations, simulated pathogen spread in targeted removals of individuals African buffalo populations when their networks have been impacted by drought [133], and simulated pathogen spread through a mouse network when infected individuals exhibit sickness behaviors [134]. Here, networks were perturbed to reflect behavioral and immunological changes caused by human disturbances in the marine environment, to model the effect of these perturbations on pathogen spread in different marine species.…”

“…For example, human activity decreases home range size for many terrestrial mammals [3], and exacerbates spatial and temporal avoidance of humans (e.g., caribous [4]; cheetahs [5]; [6], coyotes and bobcats [7]; leopards [8]). Importantly, these behavioral changes are known to impact pathogen transmission among terrestrial wildlife [9,10], but critical gaps remain, particularly for marine fauna. Most of the marine environment is currently being altered by human associated disturbances (approximately 66%) [1], and marine wildlife disease has markedly increased over the past 40 years [11]; recent reports suggest the true magnitude of marine disease is grossly underestimated [12].…”

“…host ability to both transmit and be infected by a pathogen based on their immune system's resistance and tolerance of parasites) [32]. Human disturbances influence both components of host competence in wildlife species [27,9]. For example, increased ocean temperatures can suppress diverse immune responses in corals and sea crabs, thus increasing their likelihood of infection [27].…”

“…For example, altering network connectivity to account for changes in wildlife population densities due to urbanization, translocation, or sickness behaviors (e.g. lethargy, decreased mating activity) influences pathogen transmission in terrestrial wildlife species [9].…”