Source-sink dynamics promote wolf persistence in human-modified landscapes: Insights from long-term monitoring

Abstract Long-term monitoring studies assessing wolf population dynamics are scarce, particularly in human-dominated landscapes of southern Europe. In this work, we estimate wolf demographic parameters in northwest Portugal based on a multi-methodological approach over 20 years split into two periods (period A: 1996–2005; period B: 2007–2016). Period B takes advantage of methodological upgrades in wolf surveys, as GPS telemetry and the use of genetic noninvasive samples, to report dispersal events and identify core and sink packs. The average annual population size was 27.0 ± 2.1 (SE; range 13–43) individuals, with 2 to 6 annual packs and an average density of 1.7 ± 0.1 wolves/100km2. The population showed a growth rate of 4.2 ± 7.6%, with a decreasing trend (period A, −8 ± 9%) followed by a recovery (period B, 16 ± 11%), mainly due to local extinction and reestablishment of sink packs. The average pack size was 6.2 ± 0.3 individuals, with a maximum of 16 individuals, the highest reported value for Iberian wolves. During period B, the percentage of dispersers detected in this population was 11% and the average dispersal distance was 24.8 ± 1.2 km. Core packs showed higher group persistence, breeding success, and average pack sizes compared with sink packs. Results suggest a source-sink dynamics in this population, with few core packs promoting the maintenance and recovery of sink packs through a stepping-stone process. Our findings provide a comprehensive overview of wolf population dynamics in human-dominated landscapes and reinforce that wolf management and conservation planning should take into consideration population trends based on long-term studies, and spatial dynamics of demographic traits across packs.