Unveiling population dynamics and diversity in two European brown bear (Ursus arctos) populations through non-invasive SNP genotyping

Abstract Non-invasive genetic analysis allows for monitoring and understanding population dynamics without disturbing wild animals. We present a non-invasive genetic method to identify and characterize the Cantabrian and Pyrenean (of Slovenian origin) brown bear populations. We selected an efficient panel of 61 SNPs to genotype more than 2,000 non-invasive samples from both populations. Results showed successful genotyping of 1,639 bear samples, revealing 400 different individuals. Genetic diversity was similar in both populations and differentiation between populations was highly significant. The Pyrenean population did not show genetic substructuring despite the influence of the breeding male “Pyros”. In contrast, two subpopulations are observed in the Cantabrian population. Moreover, analysis indicated a sex ratio bias in the Cantabrian population, potentially influenced by male dispersal and landscape features. Overall, the study demonstrates the utility of non-invasive genetic methods for monitoring and understanding bear populations, highlighting differences between the Pyrenean and Cantabrian populations, and providing insights into their genetic diversity, structure and demographic trends.