Barbara Boljte, Marjeta Konec, Elena Pazhenkova, Teresa Berezowska-Cnota, Tashi Dhendup, Trishna Dutta, Patrizia Giangregorio, Djuro Huber, Velichka Kardjeva, Ruben Iosif, Nadia Mucci, Barbara Promberger, Pierre-Yves Quenette, Bipan Chand Rathore, Shyamala Ratnayeke, Slaven Reljić, Nuria Selva, Sandeep Sharma, Radoslav Stanchev, Jon Swenson, Terence Kok Ju Wei, Siew Te Wong, Tomaž Skrbinšek, Tomasz Zwijacz-Kozic

Standardized monitoring methods are essential for obtaining accurate and reliable information on wildlife population status, trends, and viability, which underpin effective management and conservation. Genetic approaches based on individual genotyping are widely used for population monitoring, including for bears. However, genetic monitoring of ursids has long suffered from a lack of methodological standardization, resulting in fragmented datasets generated with different genetic markers that are not directly comparable or interoperable, even within the same population. This limits the value of genetic data for transboundary and long-term studies, as well as for direct comparisons of genetic diversity across populations.
In 2014, a new standardized approach for bear genotyping based on high-throughput sequencing of microsatellites (short tandem repeats, STRs) was presented at the International Bear Association conference in Thessaloniki, Greece. With this approach, multilocus genotypes are determined bioinformatically by analyzing directly the allele sequences, allowing genotypes generated in different laboratories and with different platforms to be shared without the need for allele size calibration. Since then, we have successfully applied this method using two co-amplifying STR panels (43 loci in total) for individual identification from invasive and non-invasive samples in seven European brown bear populations (Alpine, Apennine, Carpathian, Dinaric–Pindos, Eastern Balkan, Pyrenean, Scandinavian), one Himalayan brown bear population from India, Asiatic black bears from Bhutan, sloth bears from India and from European zoos, and sun bears from Borneo and European zoos. Here, we present results on the cross-population and cross-species performance of this method and discuss its implications for standardized genetic monitoring of bear populations and for the development of shared, interoperable bear genetic databases.