​​New model sheds light on wildlife disease transmission in urbanizing landscapes

As urbanization continues to expand globally, wild animals like foxes, coyotes, Anolis lizards and many songbirds are increasingly found in urban areas. Changes in the behavior of individual animals that allow them to thrive in cities and suburbs can result in habitat specialization, where some individuals almost exclusively use urban habitats while others use mostly natural areas. Since habitat specialization alters where and how often animals cross paths, as well as how they move across the landscape, this can affect the transmission and spread of infectious diseases, including pathogens that are shared between wildlife and people. 

CEID’s PhD graduate Dr. Claire Teitelbaum, along with professor Sonia Altizer and assistant professor Richard Hall, developed mathematical models to understand how pathogen transmission in wildlife populations is altered by urbanization. They specifically focused on animal movements and habitat specialization, which might occur when animals differ in their use of resources at a given site.

 These models examined wildlife movement across a landscape composed of patches that were classified as either natural or urban. Natural sites had fluctuating food availability while urban sites provided stable food sources, mimicking what happens when people intentionally feed wildlife or unintentionally make resources available to animals. To disentangle the influences of urbanization and specialization on wildlife population and infection dynamics, these models varied in the number of urban sites available as well as the proportion of animals specializing. 

The research team found that when no habitat specialization occurs, infection prevalence and mortality rates in wildlife were highest in natural and partially urban landscapes. This pattern is a result of higher levels of movement associated with tracking fluctuating resources in natural sites in combination with resource-stable urban sites having higher densities of individuals, promoting transmission.

When specialization occurs and animals tend to visit the same site type, the models revealed that animals have higher survival rates and lower infection prevalence because of reduced movement between natural and urban patches. Overall, these findings indicate that habitat specialization can benefit wildlife facing urban intrusion by lowering disease transmission across landscapes. It is important to note that reduced connectivity between urban and natural patches might also carry downsides, including reduced gene flow.

“The work is important for the field of movement ecology because it provides insight into the consequences of changes in animal movements in response to land-use change, both for urban landscapes and other human-dominated areas,” said lead author Teitelbaum. “These results also have implications for the management of emerging and zoonotic diseases in wildlife in human-modified landscapes.”

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by Amanda Budd