The Mosor rock lizard, Dinarolacerta mosorensis (Kolombatović, 1886), is an understudied lacertid species. It is geographically isolated within the Dinaric Alps and is categorized as Near Threatened on the IUCN Red List. Historical and newly collected records were evaluated to assess the distribution, range, and conservation status of the Mosor rock lizard. Our results show that most range localities and suitable habitats are found in Bosnia and Herzegovina and Montenegro, whereas Croatia comprises less than 2% of the total global range. We extended the species’ range further north and reconfirmed its presence west of the Neretva River. In total, we identified 33 localities—encompassing mountains, canyons, and plateaus—of which nine are new. The maximum elevation at which the species has been documented is 2,031 m a.s.l., with 91% of records occurring above 1,000 m a.s.l. The Area of Occupancy (AOO), calculated using 2 × 2 km grids, is 528 km², whereas the Extent of Occurrence (EOO) is estimated at 18,725.34 km². Despite significant variation in protected area coverage among countries, 44% of the species’ known AOO is within protected areas. Given that global climate change is the main threat to this species, there is an urgent need for targeted data collection and improved management strategies to ensure its long-term protection.

Area of Occupancy, Dinaric Alps, endemic species, Extent of Occurrence, petrophilous, protected areas, threats

The Dinaric Alps are home to numerous endemic and stenoendemic species, shaped by complex biogeographical processes and glacial periods. These mechanisms have contributed to the fragmented distribution patterns observed across multiple taxa (Đurović et al. 2021). One such species is the Mosor rock lizard, Dinarolacerta mosorensis (Kolombatović, 1886), a cold-adapted stenoendemic reptile with a fragmented distribution across mountainous regions of Croatia, Bosnia and Herzegovina, and Montenegro (Džukić 1989; Ljubisavljević et al. 2016). This species is one of two in the genus Dinarolacerta, the other being D. montenegrina Ljubisavljević, Arribas, Džukić & Carranza, 2007, found in Montenegro and Albania (Petrov 2006; Ljubisavljević et al. 2007a, 2016).

The Mosor rock lizard is primarily associated with rocky montane terrains and is usually found on limestone outcrops above the tree line or within open forest (Džukić 1991; Arnold and Ovenden 2004; Speybroeck et al. 2016). The species thrives at higher elevations (1,100–1,900 m), being present at lower elevations only in canyons and along mountain slopes in the Adriatic hinterland (Ljubisavljević et al. 2024). According to the literature, the lowest documented occurrence is at 270 m a.s.l. in the Mrtvica River Canyon (Montenegro), which is likely relictual (Ljubisavljević et al. 2016). The highest confirmed record is at Lomno Ždrijelo on Mt. Durmitor (Montenegro), at 1,900 m a.s.l. (Džukić 1991; Ljubisavljević et al. 2016). Literature records below 1,000 m a.s.l. remain rare. In Montenegro, examples include Herceg Novi – Kameno Brdo (450 m a.s.l.; Džukić 1989), and in Bosnia and Herzegovina, Mt. Baba, Ključ Valley (960 m a.s.l.; Arnold 1987). Other records from Croatia include Mt. Kozjak (580 m a.s.l.; Hunt 1957), Mt. Biokovo (Krljava, 700–800 m a.s.l.; Džukić 1989), and Mt. Mosor (750 m a.s.l.; Mekinić 2010; 900–1,000 m a.s.l.; Džukić 1989).

A phylogeographical study suggests that the species’ fragmented distribution is a remnant of a formerly wider and continuous range during colder periods and that it now occupies interglacial refugia (Podnar et al. 2014). Despite its restricted range and specific ecological requirements, detailed distributional data remain scarce. Most known localities were recorded in the late 19^th and early 20^th centuries. The first distributional overview was compiled by Bischoff (1984), and the most comprehensive review was conducted by Džukić (1989, 1991). Since then, the species’ known range in Croatia and Bosnia and Herzegovina has remained largely unchanged, with the exception of a record from Mt. Prenj in Bosnia and Herzegovina, which represents the species’ northernmost known occurrence (Šunje et al. 2014). A distribution update for Montenegro was published nine years ago (Ljubisavljević et al. 2016). Literature records west of the Neretva River are scarce. For a long time, the only confirmed localities were Mt. Mosor and Mt. Biokovo, along with one reported finding (De Luca, pers. comm.) that lacked a specific location (Džukić 1991; Ljubisavljević et al. 2007a).

The species is listed in Annex III of the Bern Convention (Council of Europe 1979) and in Annexes II and IV of the EU Habitats Directive (92/43/EEC) (Council of the European Union 2013). It is strictly protected under the Law on Nature Protection (NN 80/13, 15/18, 14/19, 127/19) in Croatia. In Montenegro, it is protected under the Decision on the Protection of Rare, Declining, Endemic, and Endangered Plant and Animal Species (Official Gazette of the Republic of Montenegro 2006). However, in Bosnia and Herzegovina, protection is partial. Under the Regulation on Strictly Protected and Protected Wild Species (Official Gazette of the Republic of Srpska No. 65/20), D. mosorensis is classified as a protected wild species. In contrast, the species is not protected in the Federation of Bosnia and Herzegovina (Federalno ministarstvo okoliša i turizma 2020; Government of the Republic of Srpska 2020).

The species is classified as “Near Threatened” in the current IUCN Red List assessment for Europe, which covers its entire range, and as “Endangered” within the EU27, which includes only Croatia (Crnobrnja Isailović et al. 2024). The primary reasons for this classification in Europe are the species’ extent of occurrence being below 16,000 km² and a continuing decline in habitat quality in at least part of its range (Crnobrnja Isailović et al. 2024). However, it remains unclear whether the population is severely fragmented or whether habitat decline is extensive enough to justify the recognition of ten or fewer locations (Crnobrnja Isailović et al. 2024).

For the EU27 (Croatia), the identified threats include diverse human-related impacts at three known locations, along with ongoing habitat degradation and loss. These factors contribute to a continued decline in habitat quality and extent and, by inference, in the number of mature individuals (Crnobrnja Isailović et al. 2024). The species’ range in Croatia is estimated at 1,528 km², representing 10% of its European distribution (Crnobrnja Isailović et al. 2024).

The national Red Lists of Croatia, the Federation of Bosnia and Herzegovina, and Montenegro classify the species as “Vulnerable” (Đug et al. 2013; Jelić et al. 2015, 2023; Lelo et al. 2016). However, the species has not been assessed in the Republic of Srpska (the other entity in Bosnia and Herzegovina) (Vlada Republike Srpske 2012).

This article aims to present unpublished data and summarize existing published records to update the known range and distribution of this endemic and relict species. Specifically, we present (1) a new distribution map, (2) a range analysis with polygon-defined localities, (3) a conservation status review based on Red List criteria, including Extent of Occurrence (EOO) and Area of Occupancy (AOO), and (4) an assessment of protected area coverage across the species’ range.

Global and European conservation status overview

Our results indicate a larger EOO (18,725.34 km²) and AOO (528 km²) compared to the last IUCN assessment (Crnobrnja Isailović et al. 2024). This increase is likely the result of additional findings in the north and west of Bosnia and Herzegovina and will likely increase further with continued mapping efforts.

The last IUCN assessment questioned whether the species was severely fragmented or restricted to 10 locations. Based on current distribution data, we tend to consider that the species occurs at more than 10 locations. There is evidence of fragmentation in the species’ distribution, with some localities (Mt. Mosor, Mt. Biokovo, Mt. Orjen, and Mt. Lovćen) forming different subpopulations due to lack of a connection. Despite the lack of major geographic barriers, the Mt. Biokovo and Mt. Mosor populations show evidence of prolonged separation (Podnar et al. 2014). Connectivity between populations on the west and east sides of the Neretva River is also questionable (Bischoff 1984; Džukić 1991). The Neretva River represents a significant barrier to gene flow for many species, including P. melisellensis (Podnar 2004; Podnar et al. 2014) and Dynaromis bogdanovi (Krystufek et al. 2007). Fragmentation across the rest of the species’ range is unclear. Considering altitude (< 1,000 m a.s.l.), populations from Mt. Prenj and Mt. Bjelašnica in Bosnia and Herzegovina to Mt. Durmitor and Mt. Prekornica in Montenegro may be connected (Fig. 2).

To date, only two phylogenetic studies have been conducted, analyzing specimens primarily from Montenegro (Ljubisavljević et al. 2007a; Podnar et al. 2014). Until future genetic or distribution studies indicate otherwise, each range locality from this study should be considered as a separate subpopulation or location according to IUCN criteria (IUCN Standards and Petitions Committee 2024).

We argue that climate change and its repercussions are the main threat to D. mosorensis. This is a cold-adapted species returning to its interglacial refugia (Podnar et al. 2014), which today are mostly higher elevations on mountaintops. Manes et al. (2021) predicted that mountain and island endemics face 84%–100% extinction risk by 2100. Montane lacertids are considered particularly vulnerable to rising temperatures, increasing aridity, and intensified competition from species better adapted to new thermal and hydric conditions (Garcia-Porta et al. 2019). Threats identified in the IUCN assessment have an unknown or minimal scope and severity (Crnobrnja Isailović et al. 2024). They appear to be local or country-specific and will be addressed below.

Although our estimates of EOO and AOO, derived using IUCN methodology, differ slightly from those in the latest IUCN assessment, this difference does not impact the species’ Near Threatened classification at either the global or European level: NT B1ab(iii).

Country-specific conservation status overview

Croatia

The last national IUCN assessment in Croatia was conducted ten years ago (Jelić et al. 2015), and an update is recommended. Our data analysis reveals that Croatia accounts for < 2% of the global range, based on range localities polygons, which differs from the 10% reported in the IUCN assessment (Crnobrnja Isailović et al. 2024).

The estimated EOO is 143.45 km², and the AOO is 84 km². The IUCN assessment for Croatia suggests three locations for this species (Crnobrnja Isailović et al. 2024); however, our data considers only two: Mt. Mosor and Mt. Biokovo. We confirm a continuing decline in the quality and extent of the species’ habitat, mainly due to the impacts of climate change. Differences in altitudinal distribution were observed on Mt. Mosor, where the species was found at lower altitudes merely 15 years ago (Mekinić 2010) but has not been observed there in several recent surveys. All of this confirms that the species’ status in Croatia is EN B1ab(iii)+B2ab(iii), as assessed for the EU 27 (which includes only Croatia) (Crnobrnja Isailović et al. 2024).

There are several other discrepancies between our observations and the IUCN threats listed for Croatia (Crnobrnja Isailović et al. 2024). Over the past seven years, we found that human activity does not significantly impact D. mosorensis habitats and populations in Croatia. On Mt. Mosor, the only human presence in the species’ habitats consists of mountaineers, as these are hard-to-reach areas. The road to the highest point on Mt. Biokovo attracts more visitors, but no roadkill was recorded. People on mountain trails are rare and do not seem to affect the species. Furthermore, since Mt. Mosor and Mt. Biokovo are part of the Natura 2000 ecological network, there are currently no plans for building large tourist resorts or establishing wind farms in areas inhabited by the species, as mentioned in the IUCN assessment. There is currently one wind farm on Mt. Mosor, but it is located at lower altitudes where the species is not present. If illegal construction of houses for tourism or personal use is taking place, it occurs at lower elevations unsuitable for the species. According to the IUCN assessment, wildfires reduce habitat quality (Crnobrnja Isailović et al. 2024), and fire-driven reptile declines have been documented (Santos et al. 2022). However, we did not observe direct mortality or changes in abundance during the 2017 wildfire on Mt. Biokovo. The affected high-altitude habitat consists of rocky grasslands, which may offer some resilience to fire. Additionally, we observed that the grassland recovered quickly and individuals were still present on the rocks. These findings highlight the need for targeted research to provide science-based evidence on the impact of wildfires on D. mosorensis. Additional studies on habitat selection are also recommended to inform appropriate conservation management (Ljubisavljević et al. 2017).

Bosnia and Herzegovina

In Bosnia and Herzegovina, there is no national Red List for D. mosorensis; however, the Federation of Bosnia and Herzegovina has assessed the species as Vulnerable (Lelo et al. 2016). The calculated EOO is 5,773.34 km², while the AOO is 136 km². There are 16 known range localities, or separate locations, each with their own short-term threats. A decline in the quality and extent of its habitat due to climate change impacts is probably ongoing. In conclusion, we argue that the species should be considered Near Threatened (NT) B1ab(iii) in Bosnia and Herzegovina. While its EOO is less than 20,000 km² (the threshold for Vulnerable under criterion B1), and habitat quality is declining, the population is not severely fragmented, there are more than 10 locations, and subpopulations do not exhibit extreme fluctuations.

In Bosnia and Herzegovina, intensive grazing in mountain areas has been identified as a threat, as it may increase predation risk (Lelo and Vesnić 2011; Crnobrnja Isailović et al. 2024). However, during our surveys, no cattle were observed in D. mosorensis habitats, though they were present nearby. While grazing can have a negative impact on reptiles (Pafilis et al. 2013), its effect on petrophilous species remains largely unexplored. The impact depends on co-evolutionary adaptations between native reptiles and introduced species, as well as an ecosystem’s area, fragility, isolation, and resilience (Pafilis et al. 2013).

Montenegro

The most recent national Red List assessment in Montenegro was conducted in 2023, categorizing D. mosorensis as Vulnerable VU B2ab(iii, v) (Jelić et al. 2023), though a detailed explanation is not available. The estimated EOO is 4,727.92 km², and the AOO is 308 km². There are 15 known range localities, or separate locations with their individual short-term threats. There is probably an ongoing decline in the quality and extent of its habitat due to climate change impacts. Therefore, although the national assessment was conducted recently, according to new IUCN guidelines available since 2024 (IUCN Standards and Petitions Committee 2024), we suggest that the species be considered Near Threatened NT under criteria B1ab(iii) + B2ab(iii). The justification for this is that while the EOO (B1) is less than 20,000 km² and the AOO (B2) is less than 500 km² (the threshold for category Vulnerable), the other conditions are not fully met. Specifically, although habitat quality is declining, the population is not severely fragmented, exists at more than 10 locations, and subpopulations do not exhibit extreme fluctuations. For Montenegro, we have no additional comments regarding the threats listed in the IUCN assessment (Crnobrnja Isailović et al. 2024).

Sympatric lizard species

It has been stated that D. mosorensis may be a weak competitor, as its occurrence is negatively correlated with the presence of all other lizards (D. Jelić pers. comm. 2023; as cited in Crnobrnja Isailović et al. 2024). Furthermore, it has been suggested that in Croatia, it seems to be restricted to higher areas without Podarcis species or Dalmatolacerta oxycephala (Jelić et al. in prep., as cited in Crnobrnja Isailović et al. 2024). This statement directly conflicts with literature and our field observations.

Sympatry between D. mosorensis and D. oxycephala was first observed on the Korito Plateau in the late 19^th century (Tomasini 1889, 1894; Werner 1907; Arnold 1987) and later on Mt. Baba, Mt. Velež (Nevesinje), and Mt. Zelengora (our observation). Although sympatry between these two species was documented long ago, no research has studied their possible syntopy. Some data reveal differences in rock height and preference for more humid areas (Arnold 1987), suggesting differences in microhabitat use. In Croatia, we also observed differences in microhabitat use between P. melisellensis/P. muralis and D. mosorensis at sites where these species occur together in the same habitat. However, these are only observations and need to be studied further. Regarding P. siculus, the species has not yet been verified in Bosnia and Herzegovina, and we have never observed it occurring in syntopy with D. mosorensis in Croatia or Montenegro.

During our research, D. mosorensis was found syntopically with three lizard species on Mt. Mosor (D. oxycephala, Algyroides nigropunctatus, and P. melisellensis), two on Mt. Biokovo (P. melisellensis and P. muralis), and two on Mt. Orjen and Mt. Lovćen (D. oxycephala and P. muralis). On Mt. Prekornica, Mt. Moračke Planine, Mt. Bioč, Mt. Maglić, Mt. Volujak, and the Sutjeska canyons, it is found sharing habitat only with P. muralis. Also notable is that D. oxycephala is present on Mt. Biokovo and Mt. Prekornica but has never been detected syntopically with D. mosorensis. It was reported that D. oxycephala is distributed up to 1,050 m on Mt. Biokovo, while D. mosorensis is found above 1,200 m a.s.l. (Schmidtler 1999). Still, our highest new recorded observations for D. oxycephala at Mt. Biokovo are at 1,230 m a.s.l., without D. mosorensis present. On Mt. Prekornica, D. oxycephala occurs below 1,150 m a.s.l.

Although some species are expected to shift to higher altitudes (Garcia-Porta et al. 2019), using only species occurrence datasets may provide false impressions. Further research is needed to determine interspecific interactions in syntopy between small Lacertidae species and D. mosorensis.

Protected areas important for species conservation

Protected areas (PAs) are fundamental to biodiversity protection. Globally, between 88.1% and 91.8% of amphibian and reptile species have less than 30% of their range within strictly protected areas, both currently and under future projections (Mi et al. 2023). The EU Biodiversity Strategy for 2030 acknowledges that the current PA network, including strictly protected areas, is insufficient to safeguard Europe’s biodiversity in the face of multiple stressors (European Commission 2020). In Europe, while the Natura 2000 network and national protected areas (NPAs) protect many amphibians and reptiles, they often underrepresent narrow-range endemics, such as those found in the Balkan Peninsula and Mediterranean islands (Abellán and Sánchez-Fernández 2015).

Climate models project declining suitability of European PAs for many species during the 21^st century. The Natura 2000 network is particularly vulnerable due to its flatland areas, where larger range losses are expected. In contrast, NPAs may offer more effective protection, partly because they are often situated in mountainous regions, which can act as climate refugia (Araújo et al. 2011). Already confined to its interglacial refugia (Podnar et al. 2014), D. mosorensis is particularly vulnerable to such future habitat shifts.

The existing PAs cover 44% of the known AOO of D. mosorensis, but the coverage varies by country. Bosnia and Herzegovina has the lowest coverage, with only 26% of occupancy grid cells protected, followed by Montenegro with 39%. In contrast, Croatia has 100% of its AOO grid cells within PAs. While all known range localities in Croatia are included in PAs, only 37.5% and 53% are included in Bosnia and Herzegovina and Montenegro, respectively. With more targeted research, the percentage of protected localities for D. mosorensis in Bosnia and Herzegovina, as well as in Montenegro, is likely to change.

According to the EU Habitats Directive, proposed Natura 2000 sites should cover 20% to 60% of a species’ total population in a given biogeographical region. Protecting 60% should generally ensure Favorable Conservation Status (FCS) (The European Topic Center on Biological Diversity n.d.). As EU candidate countries, Bosnia and Herzegovina and Montenegro are expected to develop a Natura 2000 network in the future. Since the distribution of D. mosorensis in both countries lies within the Mediterranean and Alpine biogeographical regions, aiming for the highest possible percentage of protection in each region is strongly recommended.

This study significantly expands the known distribution of D. mosorensis by identifying nine new range localities. The newly discovered sites include Mt. Čvrsnica, Mt. Visočica, Mt. Bjelašnica, Mt. Treskavica, Mt. Romanija, Mt. Bioč, Mt. Moračke planine, and the Rakitnica and Sutjeska Canyons. Additionally, we reconfirm the species’ presence on two mountains, Mt. Volujak and Mt. Čabulja, which were not included in previous distribution reviews. Our discoveries in canyons substantiate the notion that studies should encompass not just suitable habitats at high elevations but also potential refuge habitats in gorges and canyons at lower elevations. We extended the species’ range further north and west of the Neretva River and identified distribution gaps in Bosnia and Herzegovina and Montenegro where D. mosorensis may be present. The highest recorded species occurrence is now at a new maximum of 2,031 m a.s.l. on Mt. Volujak.

Our findings support previous observations that D. mosorensis thrives at higher elevations (1,100–1,900 m), with its presence at lower elevations restricted to canyons and mountain slopes in the Adriatic hinterland. We argue that the range localities should be considered as separate locations according to IUCN criteria, as their connectivity remains uncertain. We are confident that the populations on Mt. Mosor and Mt. Biokovo, as well as Mt. Orjen and Mt. Lovćen, represent distinct and unconnected subpopulations.

We emphasize the necessity for further comprehensive investigation into the species’ presence at lower elevations. Continuous monitoring is essential to determine if, and how quickly, the species is retreating from these areas, as our findings on Mt. Mosor suggest. It is critical to revisit all lower-altitude sites with historical records of the species’ presence, like the Korito Plateau, Kameno Brdo, etc., as these are the initial areas where the species’ survival is jeopardized due to climate change.

Establishing new protected areas (PAs) is fundamental for the conservation of this species, particularly in Bosnia and Herzegovina. However, it is equally crucial to intensify research efforts focused on this species. The Mosor Rock Lizard remains inadequately studied, with few exceptions in Montenegro. Climate change and related threats, along with scientists’ predictions, do not suggest a positive future for this endemic and relict Dinaric species. Future research should focus on species distribution modeling, genetic studies, and ecological investigations to better understand population and habitat structures, fragmentation, interactions, potential threats, and interspecific relationships. These efforts will be crucial for developing effective, evidence-based conservation strategies to protect the species.

We express our gratitude to our families, colleagues, and friends who contributed to the fieldwork or shared their data with us: M. Blažić, V. Lazić, Đ. Majetić, T. Koren, M. Zadravec, B. Horvatić, S. Mekinić, A. Džukić, and A. Zimić. We are also grateful to G. Gassner and S. Schweiger from the NHMW for providing data and to the staff of NP Biokovo, with special thanks to I. Gabrić for her technical and expert support over the years.

Data collection in Croatia was partially supported by the public institution “Biokovo Nature Park” (2018–2021) and the Croatian Ministry of Economy and Sustainable Development through the project Development of monitoring programs for herpetofauna with capacity building for stakeholders involved in monitoring and reporting, Group 9 (OPKK project, 2021–2023).

All necessary research permits were obtained from the relevant authorities. In Croatia, permits were issued by the Ministry of Environmental Protection and Green Transition (permit nos. UP/I-612-07/18-48/54, UP/I-612-07/19-48/45, UP/I-612-07/20-48/38, UP/I-352-04/22-08/75, UP/I-352-04/24-08/87). In Bosnia and Herzegovina, permits were granted by the Federal Ministry of Environment and Tourism (no. 04-19-366/21-16) and the Republic Institute for the Protection of Cultural, Historical, and Natural Heritage of the Republic of Srpska (nos. 30/625-484/18, 30/625-435/19, 30/625-573/21, 30/625-304/22, 30/625-385/23). In Montenegro, data were collected under the NATURA 2000 project by the Environmental Protection Agency of Montenegro, from which we obtained consent for data use.