Data from: Interactions between demography, genetics, and landscape connectivity increase extinction probability for a small population of large carnivores in a major metropolitan area

The extinction vortex is a theoretical model describing the process by
which extinction risk is elevated in small, isolated populations owing to
interactions between environmental, demographic, and genetic factors.
However, empirical demonstrations of these interactions have been elusive.
We modelled the dynamics of a small mountain lion population isolated by
anthropogenic barriers in greater Los Angeles, California, to evaluate the
influence of demographic, genetic, and landscape factors on extinction
probability. The population exhibited strong survival and reproduction,
and the model predicted stable median population growth and a 15%
probability of extinction over 50 years in the absence of inbreeding
depression. However, our model also predicted the population will lose
40–57% of its heterozygosity in 50 years. When we reduced demographic
parameters proportional to reductions documented in another wild
population of mountain lions that experienced inbreeding depression,
extinction probability rose to 99.7%. Simulating greater landscape
connectivity by increasing immigration to greater than or equal to one
migrant per generation appears sufficient to largely maintain genetic
diversity and reduce extinction probability. We provide empirical support
for the central tenet of the extinction vortex as interactions between
genetics and demography greatly increased extinction probability relative
to the risk from demographic and environmental stochasticity alone. Our
modelling approach realistically integrates demographic and genetic data
to provide a comprehensive assessment of factors threatening small
populations.