Individual behaviors dominate dynamics of an urban mountain lion population isolated by roads

This study combined GPS tracking and genetics to show how major roads isolate a mountain lion population in the Santa Monica Mountains, with freeways acting as near-total barriers to movement. The authors documented that the few crossings, and the behaviors of individual cats, dominated the population's connectivity and genetic outcomes, and that isolation was already producing signs of inbreeding. The work is widely cited for vividly demonstrating how urban infrastructure fragments large-carnivore populations and for motivating the construction of wildlife overpasses. It illustrates that habitat for wide-ranging cats is defined not just by land cover but by permeability, and that roads can functionally shrink a population's world to a fragment.