Unsecured attractants, collisions, and high mortality strain coexistence between grizzly bears and people in the Elk Valley, southeast British Columbia

Historical persecution of grizzly bears in North America reduced the species range by 55%. Today, dedicated recovery efforts and shifting societal perceptions have supported the recovery and expansion of grizzly bear populations in many areas. With increasing overlap between people and bears, conservation actions and scientific inquiry are now shifting efforts toward supporting coexistence with bears. Here, we assessed the demography and behavior of grizzly bears in a coexistence landscape in southeast British Columbia, Canada, where abundant grizzly bear populations occur among busy, human-settled valleys. Between 2016 and 2022, we captured 76 individual grizzly bears and monitored their conflict behavior, survival, and reproduction for 160 animal-years. The cause of death for 14 animals with a functioning collar was human-wildlife conflict (n = 6), road or rail collision (n = 6), unknown but human suspected (n = 1), and natural (n = 1). Subadult survival was the lowest recorded in North America, while adult survival was similar to other studies, suggesting an intense demographic filter for young animals. We estimate that human-caused mortality is underreported in government databases by 65%, or for every recorded mortality, there are similar to 2 that go unreported. Reporting was especially low for road and rail mortalities. Grizzly bear mortality in the Elk Valley due to collisions and conflicts with people is an order of magnitude greater than elsewhere in British Columbia. Combining DNA- and collar-based estimates of population growth, we show that grizzly bear abundance is stable due to source-sink dynamics, whereby similar to 7 immigrant bears per year offset the high mortality rates in the area. Grizzly bears dispersing into the valley are often young and more conflict-naive, creating a conflict spiral that can be interrupted by reducing mortality of young animals. Creating a self-sustaining population of bears in the Elk Valley that is not reliant on immigration will require targeted efforts to reduce or secure attractants on private property and strategies to minimize collisions with trains and vehicles.

Automated summary

Historical persecution greatly reduced the range of grizzly bears in North America, but recent recovery efforts and changing societal perceptions have led to their population recovery and expansion. This study focused on grizzly bears in southeast British Columbia, Canada, where their populations coexist with human settlements. The research found that human-caused mortality is significantly underreported, with road and rail collisions being particularly low in reporting. Grizzly bear mortality in the Elk Valley is much higher compared to other regions in British Columbia. To create a self-sustaining population in the Elk Valley, targeted efforts are needed to reduce attractants on private property and minimize collisions with trains and vehicles.