California mountain lions are not fully protected from humans

California mountain lions continue to be threatened by human activities, despite being classified as specially protected mammals, according to a study led by the University of Nebraska-Lincoln. 

The California Wildlife Protection Act of 1990 made it illegal to hunt mountain lions, but the researchers have determined that human-caused mortality is still more common than natural mortality among these animals. The biggest threats were found to be vehicle collisions and conflict with humans over livestock.

For the investigation, experts from multiple universities, government agencies, and private organizations tracked hundreds of mountain lions across the state of California. The animals were located in many different study areas, including the Sierra Nevada Mountains and the city of Los Angeles.

“Population dynamics of large carnivores operate at large scales, making it critical for researchers to collaborate across broad geographic regions that go beyond typical study areas to better understand population processes and connectivity,” explained study co-lead author Professor John Benson.

The analysis revealed that mountain lions were at greater risk of human-caused mortality when they were closer to rural development. Mountain lions were found to be less threatened in areas where more voters favored pro-environmental initiatives.

“Ecologists believe that human tolerance is critical to conserving large carnivores in landscapes shared with humans. However, it is rare that data on tolerance are included in the models we use to understand mortality risk,” said Professor Benson. “Of course, we acknowledge that voting records on environmental issues are not a direct reflection of this tolerance, but the strength of this result suggests that human mindset may be an important driver of mortality risk for mountain lions.”

According to the experts, the new research highlights the importance of understanding interrelationships between different populations across California for long-term conservation of the species.

“Young male mountain lions often move and breed long distances from where they were born, and are largely responsible for maintaining gene flow between populations,” said study co-lead author Kyle Dougherty. “Immigration of mountain lions from adjacent or more distant populations can also help compensate for high rates of human-caused mortality and maintain population persistence through a process known as ‘source-sink’ dynamics.”

“We tend to focus on survival of adult females because of their strong influence on growth or decline of individual populations,” said study co-author Justin Dellinger. “However, young males are the ones that move between populations meaning that their mortality, combined with barriers to movement imposed by roads and development, could limit the utility of seemingly healthy populations to act as ‘sources’ of new animals and genes for small, isolated populations.”

The study is published in the journal Proceedings of the National Academy of Sciences. 

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By Chrissy Sexton, Earth.com Editor

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