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Species range expansions and (re)colonization of landscapes variously dominated by humans occur on a global scale. Understanding such range enlargements and subsequent changes in the composition of ecological communities is important for conservation management, and the golden jackal (Canis aureus) can be considered a model species for regional and continental range expansion. Although this mesopredator has been known from the Adriatic Coast of southeastern Europe for over 500 years, the species is a recent arrival further north, including in Slovenia where jackals were first confirmed in the 1950s. Research from eastern Italy found jackals with ancestry from the Dalmatian region on the Adriatic Coast and the Pannonian region further east. We predicted similar ancestry for Slovenian jackals, and examined samples from Croatia, including Dalmatia and interior regions, Serbia, Hungary, and Slovenia with 25 microsatellite markers to determine population genetic structure. We detected two distinct genetic clusters, representing the Dalmatian and Balkan-Pannonian (Pannonian) jackal populations (F$_{ST}$ = 0.157, 95% CI: 0.112–0.209). Contrary to expectations, only few individuals in Slovenia exhibited signs of Dalmatian ancestry, and none appeared to be direct immigrants. Some results suggested a third cluster centered in northern Hungary. These divergent profiles might indicate immigration from outside the study area, and samples from regions further east are required for additional resolution. Based on our results, we hypothesize that Dalmatia has not been a substantial source for recent range expansion of the species, which has likely occurred from the east. Further investigation can help resolve the ancestry and current distribution of the Dalmatian and Pannonian populations, and the ecological relationships resulting from progressively overlapping distributions of canid species. Finally, genomic research could illuminate whether genetic variants from eastern areas might have facilitated jackal expansion into regions characterized by a colder climate, the presence of snow, and extensive forest cover habitats seemingly avoided by the jackals occupying the Adriatic Coast and surrounding areas in southeastern Europe.

Regular assessments of species’ status are an essential component of conservation planning and adaptive management. They allow the progress of past or ongoing conservation actions to be evaluated and can be used to redirect and prioritize future conservation actions. Most countries perform periodic assessments for their own national adaptive management procedures or national red lists. Furthermore, the countries of the European Union have to report on the status of all species listed on the directives of the Habitats Directive every 6 years as part of their obligations under Article 17. However, these national level assessments are often made using non-standardized procedures and do not always adequately reflect the biological units (i.e., the populations) which are needed for ecologically meaningful assessments. Since the early 2000’s the Large Carnivore Initiative for Europe (a Specialist Group of the IUCN’s Species Survival Commission) has been coordinating periodic surveys of the status of large carnivores across Europe (e.g., von Arx et al. 2004; Salvatori & Linnell 2005, Kaczensky et al. 2013). These have covered the Eurasian lynx (Lynx lynx), the wolf (Canis lupus), the brown bear (Ursus arctos) and the wolverine (Gulo gulo). The golden jackal (Canis aureus) has been added to the LCIE prerogatives in 2014. The species is rapidly expanding in Europe (Trouwborst et al. 2015; Männil & Ranc 2022), a large-scale phenomenon that resembles that of the other large carnivores. Golden jackals are thriving in human-dominated landscapes (Ćirović et al. 2016; Lanszki et al. 2018; Fenton et al. 2021), where they are often functioning as the top predators, despite having smaller body size that is typical for large carnivores. The expansion of the species triggers many questions among scientists, stakeholders, and policy makers (Trouwborst et al. 2015; Hatlauf et al. 2021), that are closely connected to those raised by the other large carnivores (e.g., potential conflicts with livestock or hunting). In this context, monitoring the species’ expansion, delineating populations, assessing the species' legal and protection status, and addressing the concerns raised by this rapidly expanding carnivore requires a high level of coordination among regional experts. These surveys involve the contributions of the best available experts and sources of information. While the underlying data quality and field methodology varies widely across Europe, these coordinated assessments do their best to integrate the diverse data in a comparable manner and make the differences transparent. They also endeavor to conduct the assessments on the most important scales. This includes the continental scale (all countries except for Russia, Belarus, Moldova and the parts of Ukraine outside the Carpathian Mountain range), the scale of the EU 28 (where the Habitats Directive operates) and of the biological populations which reflect the scale at which ecological processes occur (Linnell et al. 2008). In this way, the independent LCIE assessments provide a valuable complement to the ongoing national processes. Our last assessments covered the period 2006-2011 (Kaczensky et al. 2013; Chapron et al. 2014) but, at the time, did not include golden jackals. The current assessment is based on the period 2012-2016 and broadly follows the same methodology. Explicit distinctions are made between classification based on empirical data and expert opinion. The population definitions used in this report follow those proposed in (Ranc et al. 2018); areas whose presence category was defined by expert opinion were not assigned to a specific population, though.

Additional file 1. Table S1. List of DLA-DQA1 Canid alleles downloaded from the IPD-MHC database.