Camera traps advance UM study on wildlife and urbanization

Cassidy Motahari

Christopher Hansen, a postdoctoral research associate in the Boone and Crockett Wildlife Conservation Program at the University of Montana, wanted to better understand how human development affects wild mammals in Missoula.

Hansen placed more than 170 camera traps – discrete, motion-trigged cameras used to survey wildlife with minimal disturbance – in randomly selected locations across the city and surrounding areas. The camera traps were deployed from May to October in 2019 and 2020.

According to Hansen, almost every camera trap, ranging from those in density-populated neighborhoods to Lolo National Forest and the border of the Rattlesnake Wilderness Area, recorded a wild mammal at some point during the study.

“It goes to show that there’s wildlife everywhere,” Hansen said. “And we’re living amongst it.”

The resulting study, recently published in the Journal of Mammalogy, reveals how urbanization is changing Missoula’s wildlife, including which mammal species are thriving among Missoula residents and which may be most negatively impacted by human development.

Using the data collected by the traps, Hanson, along with researchers from North Carolina State University and the North Carolina Museum of Natural Sciences, determined that the number of mammal species in a given area sharply declined as housing density increased.

The most commonly recorded species in Missoula’s urban areas included white-tailed deer, raccoons, and eastern fox squirrels. Moose, American martins, badgers and gray wolves were found to be especially sensitive to urbanization and were only recorded in areas with minimal or no human development.

These results underscore the importance of maintaining natural areas to conserve species that cannot survive in developed areas, according to the researchers.

“Assuming we maintain our national forests and our public lands, and they’re not getting built up, I think we’re in a good position for the future,” Hansen said.

With an estimated 77,000 residents in 2022, Missoula’s population has grown by about 4% since 2020, according to U.S. Census data. Rising population is one of the factors that drives increasing residential development in Missoula, according to Ben Brewer, long range planning supervisor at the city of Missoula.

“We need to anticipate, and even incentivize, growth and development to be able to make room and space for the people that are here now. Not to mention people who are going to come here in the future,” Brewer said.

861 Missoula housing units were permitted in 2022, a sharp increase from the 476 in 2020, according to a report by the city. More than 1,300 units were permitted in 2021, partly due to the approval of a large apartment complex.

Human-wildlife conflict is bound to increase as Missoula continues to grow, according to Eli Hampson, lion and bear management technician at the Montana Department of Fish, Wildlife and Parks. More people create more attractants, such as garbage, gardens and bird feeders. These attractants can lure animals, including bears, into more populated areas.

Hampson also said that urban sprawl is contributing to an increase in human-wildlife conflict in Missoula’s surrounding areas.

“Even outside of Missoula, we are seeing a lot of these new homes being built; new neighborhoods, new subdivisions,” said Hampson. “A lot of folks that have just moved out here really aren’t accustomed to living here, to living with wildlife. We’re seeing a lot of conflicts due to that as well.”

Hampson also says that education plays a significant role in reducing human-wildlife conflict. Hampson points to the website MissoulaBears.org as a resource, which provides updates on recent wildlife sightings and instructions on storing attractants to minimize the likelihood of bears becoming habituated to residential areas.