After centuries of intense persecution, several large carnivore species in Europe and North America have experienced a rebound. Today's spatial configuration of large carnivore populations has likely arisen from the interplay between their ecological traits and current environmental conditions, but also from their history of persecution and protection. Yet, due to the challenge of studying population-level phenomena, we are rarely able to disentangle and quantify the influence of past and present factors driving the spatial distribution and density of these controversial species. Using spatial capture-recapture models and a data set of 742 genetically identified wolverines Gulo gulo collected over ½ million km² across their entire range in Norway and Sweden, we identify landscape-level factors explaining the current population density of wolverines in the Scandinavian Peninsula. Distance from the relict range along the Swedish-Norwegian border, where the wolverine population survived a long history of persecution, remains a key determinant of wolverine density today. However, regional differences in management and environmental conditions also played an important role in shaping spatial patterns in present-day wolverine density. Specifically, we found evidence of slower recolonization in areas that had set lower wolverine population goals in terms of the desired number of annual reproductions. Management of transboundary large carnivore populations at biologically relevant scales may be inhibited by administrative fragmentation. Yet, as our study shows, population-level monitoring is an achievable prerequisite for a comprehensive understanding of the distribution and density of large carnivores across an increasingly anthropogenic landscape.

Details on wolverine Gulo gulo data are provided by Moqanaki, E. et al. (here and here) and additional references are given. In brief, this dataset include wolverine noninvasive genetic sampling data extracted from the Scandinavian large carnivore monitoring database (Rovbase 3.0; www.rovbase.no and www.rovbase.se). Wildlife authorities and volunteers conducted both structured searches and opportunistic sampling of putative wolverine scats and hair on snow throughout the species’ range in Norway and Sweden. The structured search tracks and locations of noninvasive samples were GPS recorded. Samples were then processed and analyzed by two dedicated DNA labs using a number of control measures to minimize genotyping errors. First, samples were analyzed with a Single Nucleotide Polymorphism (SNP)-chip with 96 markers. Second, all individuals were analyzed with 19 microsatellite markers to determine species and identity of wolverine individuals as well as their sex. The dataset contains noninvasive genetic sampling data of the wolverine collected between 1 December 2018 and 30 June 2019, which consists of individual identity, sex, collection date, and coordinates associated with each wolverine sample. More information about the additional filtering steps can be found here and here.

This dataset is extracted from the database Rovbase 3.0 at www.rovbase.no or www.rovbase.se. Please read the README file. The data and R scripts of the spatial capture-recapture analysis are also available at: https://github. com/eMoqanaki/WolverineDensitySCR