The taxonomy of this species was long contentious, however Stümpel et al. (2016) determined that European populations from Thrace and those from western Anatolia relate to M. xanthina, whereas populations from central and eastern Anatolia and the Levant relate to Montivipera bornmuelleri, M. bulgardaghica-albizona and M. wagneri (the latter two sometimes treated as subspecies of M. bornmuelleri) (Geniez 2018, Freitas et al. 2020, Mebert et al. 2020, Ahmad et al. 2021).

Morphological and molecular variation suggests that M. xanthina is a complex of three to four taxa but data are presently insufficient to warrant taxonomic changes at the species level (Stümpel et al. 2016). Nonetheless, four new subspecies have been described for European populations based on morphological data: M. x. occidentalis from the Evros region in Greece (Cattaneo 2017); and M. x. nilsoni on the Aegean island of Chios with where the largest specimens known for this species are found; and M. x. dianae from the island of Leros Island (Cattaneo 2014); and M. x. varoli Afsar, Yakin, Çiçek & Ayaz, 2019.

European regional assessment: Least Concern (LC)
EU 27 regional assessment: Least Concern (LC)

The Ottoman Viper is assessed as Least Concern in view of its wide distribution, large population, and because it is unlikely to be declining fast enough to qualify for listing in a threatened category. Although it has a restricted area of occupancy as presently understood, the major human impacts on its population are concentrated in the Aegean islands that represent a little less than a third of the area of occupancy, and it can persist at the margins of agricultural land and it does not occur in fewer than ten threat-defined locations, or as a severely fragmented population.

In Europe, this species is restricted primarily to southern areas of Thrace, extending at least from the riparian slopes of Kompastos River north of Poliantho (G. Kreiner pers. comm.) east across the Rhodopes and Eyros regions (Greece) and through Turkish Thrace to Istanbul and south into the Gallipoli Peninsula. Preliminary data suggest that its range boundary in the north (which is further south than previously believed, as a number of records further north included in an earlier Red List assessment - Böhme et al. 2009 - were in error) is defined by a combination of dense forest, a reduced area of rocky habitats, and the presence of the nose-horned viper (Vipera ammodytes) north of the Ottoman viper's range. In Turkish Thrace there is a range disjunction of up to 100 km between the Yildiz/Istranca Mountains to the coastal hills and mountains along the Aegean Sea (Werner 1914, Joger and Nilson 2005, Kurnaz et al. 2018). This is a flat area of extensive agricultural land, but there are a number of wooded, grassy or rocky patches that may support small viper subpopulations.

It also occurs on a number of associated islands: from north to south Samothrace, Imbros, Lesbos, Chios, Inousses/Oenousses, Samos, Patmos, Lipsi, Leros, Kalymnos, Kos and Symi (Speybroeck et al. 2021). It has been reported from the islet of Kalolimnos (Papakonstantinou et al. 1995). The species was reported from Chalki in the Rhodes Archipelago by E. v. Oertzen in Boettger (1988), however subsequent work has not confirmed its occurrence on this island (Cattaneo 2009), and it is possible that this report may reflect confusion with the coin-marked snake (Hemmorhois nummifer) (Joger and Nilsson 2005), or that it was taken elsewhere in the Rhodes Archipelago (e.g. Alimia) on an island where the species has not yet been detected (Grano et al. 2015). A juvenile snake superficially resembling this viper has been observed on Tilos Island (Broggi 2006), but may correspond to a known species from that island rather than the Ottoman viper (Cattaneo 2009, M. Broggi pers. comm.). Further work on Tilos has failed to record this species, and there are no known reports of venomous snakebites on the island (S. Roussos and Isailovic, pers. comms.), and the species is not considered to be part of the Tilos fauna pending confirmation of its extant or former occurrence on this island (Grano et al. 2018). It is largely restricted to coastal hills in its European range (Speybroeck et al. 2016), but has been recorded to at least 600 m asl. on Chios (I. Strachinis pers. obs.).

Outside the European region, the species occurs only in Türkiye, where it is known only from western, southern and central Anatolia, and the islands Imbros (Yakin et al. 2018) and Kiz (Bruno 1985). It ranges from sea level up to more than 2,000 m asl in Asian Türkiye (Speybroeck et al. 2016, Geniez 2018).

The species can be common in upland areas and on islands, although it is localised or occurs thinly in lowland landscapes characterised by intensive agriculture. Although a number of large subpopulations occur in mainland Greece only six records are known from Turkish Thrace. On Aegean islands it can be either extremely rare or locally abundant, and further research is needed across its range to better understand spatial variation in population densities.

This species is found in Mediterranean scrubland (maquis) and mountain steppe habitats. It can be found in rural gardens, cultivated land, olive groves and among ruins. The females give birth to up to 20 live young (Dimaki 2021, Speybroeck et al. 2016). Subpopulations from Thracian lowlands seem to exhibit a particular association with ecotones (hedges, forest edges, riparian structures) within or adjacent to agricultural areas, where these provide sufficient microhabitat complexity for shelter and prey (Cattaneo and Cattaneo 2014).

On the Eastern Aegean and Dodecanese islands of Greece the snake occupies a range of habitats as the islands differ drastically in size, biodiversity, water availability, and age. On the smaller islands that are more dry and less diverse, the species inhabits the more mesic areas. Where vegetation is more dense (providing more cover, prey and sites for thermoregulation) it is often found in valleys, flat agricultural areas, gardens, stone walls and terraced fields. On larger islands it can inhabit a broader range of habitats where these remain diverse.

Hibernation can last up to five months at higher elevations, but is much shorter in lowland areas (Geniez et al. 2018, Stümpel et al. 2019). Females give birth to up to 20 live young (Speybroeck et al. 2016).

The most relevant threats in Europe are those related to ongoing habitat degradation, primarily through a replacement of habitat by intense agricultural and urban development and roads, but also use of pesticides and wildfires. A low rate of collection for the international pet trade or other purposes may be ongoing, along with local persecution on touristed Aegean islands, but any impacts are negligible in comparison to habitat loss (Mebert et al. 2020).

On many larger Aegean islands heavy urban development and habitat modification for agriculture has both reduced habitat diversity and increased pressure on water qu ality, and invasive predators such as cats may also exert pressure on island snake subpopulations. This development also increases the snake's exposure to both persecution and road mortality. Overgrazing by goats is also a threat to habitat quality on a number of islands.

This species is collected for the international pet trade, with animals apparently sourced mainly from Türkiye. Greek villagers have killed animals and extracted its heart, claiming to obtain its vital force this way (Cattaneo and Cattaneo 2013)

This species is listed on Annex II of the Bern Convention and on Annex IV of the EU Habitats Directive. It is present in many protected areas in both European Türkiye and Greece. Research is recommended in the flatlands of Turkish Thrace where small viper subpopulations may occur in remnant vegetation patches or areas unsuitable for agriculture.