Data from: Monitoring the effective population size of a brown bear (Ursus arctos) population using new single-sample approaches

The effective population size (Ne) could be the ideal parameter for
monitoring populations of conservation concern as it conveniently
summarizes both the evolutionary potential of the population and its
sensitivity to genetic stochasticity. However, tracing its change through
time is difficult in natural populations. We applied four new methods for
estimating Ne from a single sample of genotypes to trace temporal change
in Ne for bears in the Northern Dinaric Mountains. We genotyped 510 bears
using 20 microsatellite loci, and determined their age. The samples were
organized into cohorts with regard to the year when the animals were born
and yearly samples with age categories for every year when they were
alive. We used the Estimator by Parentage Assignment (EPA) to directly
estimate both Ne and generation interval for each yearly sample. For
cohorts, we estimated the effective number of breeders (Nb) using Linkage
Disequilibrium, Sibship Assignment and Approximate Bayesian Computation
methods, and extrapolated these estimates to Ne using the generation
interval. The Ne estimate by EPA is 276 (183-350 95% CI), meeting the
inbreeding-avoidance criterion of Ne > 50 but short of the
long-term minimum viable population goal of Ne > 500. The results
obtained by the other methods are highly consistent with this result, and
all indicate a rapid increase in Ne probably in the late 1990s and early
2000s. The new single-sample approaches to estimation of Ne provide
efficient means for including Ne in monitoring frameworks, and will be of
great importance for future management and conservation.