Colorado State Researchers Study Impact of Habitat Fragmentation on Disease Transmission Among Wild Big Cats

The National Science Foundation awarded Colorado State University scientists a $2.3 million grant to study how habitat fragmentation in parts of the United States influences the transmission of diseases among bobcats, pumas and domestic cats. This work will ultimately help scientists in the future identify how urbanization influences the dynamics of infectious disease among wildlife populations and domestic pets.  

Kevin Crooks, associate professor in the Department of Fish, Wildlife and Conservation Biology, and Sue VandeWoude, associate professor in the Department of Microbiology, Immunology and Pathology, will study the three different cat species in divergent habitats in Colorado, Florida and California as part of a National Science Foundation Ecology of Infectious Diseases research program.     

Bobcats and pumas share overlapping habitats in these regions, are susceptible to many of the same diseases and are at risk of infection with some domestic cat pathogens. Hundreds of outdoor domestic cats roam around urban edges with some access to adjacent natural areas, potentially coming into contact with wild cats. Scientists will study to what extent disease agents in puma and bobcat populations are found in domestic cats. Some of these diseases, such as toxoplasmosis and bartonella, or cat scratch disease, can also infect humans.

"We’re interested in discovering how ‘pile-up’ or restriction of the home ranges of these species along urban edges affect the transmission of diseases relative to incidence in more rural areas. We suspect that the spectrum of pathogens and the rate of infection changes as habitat fragmentation forces those species to live in closer proximity," said VandeWoude, principal investigator on the study.

The scientists will look for a trend between disease dynamics and urban fragmentation among feline species in high density places such as Los Angeles and the Colorado Front Range compared to more rural areas. Ultimately, they hope to understand the relationship between urbanization and the prevalence of cross-species disease transmission.

VandeWoude’s lab specializes in the study of a common feline disease, feline immunodeficiency virus, or FIV, which creates a lifelong infection and can be fatal to infected animals. Bobcats, pumas and domestic cats each have its own specific FIV strain. VandeWoude and Crooks will study how the strains are similar across species and locations, providing insight into connectivity within and among populations.

Preliminary studies have shown that large wild cats share FIV strains in California and Florida in restricted habitats, demonstrating rare cross-species virus transmission.

Habitat fragmentation has been targeted as one of the most serious threats to biological diversity worldwide; urbanization is a leading agent of fragmentation and cause of species endangerment. Landscape-level connectivity is essential to natural processes for animals and plants. Where connectivity is not retained across developing landscapes, many plant and animal populations may eventually disappear.

Both pumas and bobcats are sensitive to urban fragmentation and require connectivity for mere existence. Rapidly expanding human development is increasingly encroaching on remaining natural habitat for both species. Rural areas are growing at a rate faster than urban areas in the West, creating rural sprawl in many areas.

Crooks, VandeWoude and collaborators use GPS collars to track the movement of bobcats and puma movements through urban and rural areas. The tracking data will offer insight to scientists as to how urbanization influences movement patterns, contact rates and disease transmission between bobcats, pumas and domestic cats.

The researchers also will collect blood samples from wild cats and from domestic cats that may have been feral that are brought to area shelters to research disease cross-species transmission.

For more than a decade, Crooks has conducted intensive studies in southern California tracking carnivore movements in urbanized landscapes using radio collars, remotely-triggered cameras and track surveys.

Fellow collaborators on this project include Drs. Michael Lappin and Mo Salman at Colorado State, and colleagues at the Colorado Division of Wildlife, U.S. Geological Survey, National Park Service, National Institutes of Health, University of California Davis and the University of Florida.