A modeling lens on landscapes-of-peril and other ecological drivers of zoonoses

Wayne Marcus Getz , Kathleen A Alexander, Richard Salter, Joel S Brown, Chadi Saad-Roy

Ecological systems are driven by a complex suite of environmental conditions, interactions among individuals, and reciprocal behavioral and biological responses of organisms to the ecosystems they inhabit. Individuals may, in turn, reshape those systems, generating feedback that alters the ecological drivers influencing subsequent system dynamics. Extractive and competitive processes are embedded within responses to
predation and infection risk, shaped by perceived hazard together with
resource value and individual state. Peril need not be perceived, however,
to bear on fitness and pathogen transmission. Exposure arises from the intersection of a pathogen landscape that is a property of place with what animals do there, and infection from the state that determines susceptibility to a
given dose. These interdependent dynamics can scale upward to influence
successional, ecological, and evolutionary processes over time. An emerging framework for incorporating fear and disgust as ecological drivers is the landscape of peril (LOP), which integrates predation and infection risks across heterogeneous environments. LOPs provide a means of characterizing when and where individuals move, how they allocate time among resource patches, and the activities in which they engage at a location in response to spatially and temporally varying hazards. These state-dependent decisions can influence pathogen-transmission dynamics by altering contact between susceptible and infected individuals, the structure of contact networks, opportunities for exposure, host susceptibility, and pathogen shedding. Humans now exert a transformative influence on ecological systems and are major drivers of global environmental change. Humans may also experience ecosystem-dependent landscapes of peril of their own. Their responses to these perceived risks can shape land use, resource distributions, infrastructure, waste, wildlife management, human behaviors associated with tolerance, exclusion, and persecution, thereby engineering the environmental conditions and spatial gradients of risk encountered by other species. Wildlife responses may subsequently feedback to alter human perceptions and actions, although the strength and direction of this feedback will vary with communities and human populations. In this chapter, we develop a framework for identifying the ecological, environmental, anthropogenic, and state-dependent drivers of zoonotic processes that are most salient for agent-based modeling. We explicitly consider the role of human landscapes of peril and the mechanisms through which human perceptions and actions influence the landscapes of peril experienced by wildlife. We propose that future studies incorporate these processes within a modeling framework that we term PEARLS: Peril, Environmental, Anthropogenic, and Resource Landscapes and States. We illustrate the application of this framework using enzootic tuberculosis caused by Mycobacterium mungi, a member of the M.~tuberculosis complex, in a population of banded mongoose (Mungos mungo) occurring across a human–wildlife continuum in Northern Botswana.