Complementary analyses of geneticMinimum Viable Population size ofScandinavian bears (Ursus arctos)

This short report presents the results of analyses and assessment of genetic Minimum Viable Population size of Scandinavian bears (Ursus arctos) that complement the population viability analyses already performed by Torbjörn Nilsson (2013). This is one of the scientific reports underpinning the Swedish Environmental Protection Agency’s Article-17 reporting in 2013 of Favourable Reference Population size for the brown bear in Sweden. It presents complementary population viability analyses of the Scandinavian population with the VORTEX software to quantify minimum viable population size (MVP) estimates in relation to two criteria for genetic viability. The analyses were based on simulations without immigration and mutation, and using the same demographic data from empirical studies of the Scandinavian population as were used in a previous SEPA report (6549), except for the updated data on the reproductive success of males. The genetic MVP corresponding to < 5% loss of genetic variability (i.e. heterozygosity) in 100 years was estimated at > 380 bears when effects of catastrophes were not simulated, and at > 400 bears when effects of rare catastrophes were included. The genetic MVP corresponding to an effective population size (Ne) of > 500 was estimated at > 2250 bears when effects of catastrophes were not simulated, and at > 2350 bears when rare catastrophes were included. The study approach and results are discussed, for example, in relation to the two MVP criteria, FRP, and to the degree of genetic differentiation and isolation of the Scandinavian bear population