This species was included in the subgenus Stereosa (Verdugo 2005) but more recently, it was changed to the subgenus Cypriacis (Kubáň 2006, 2016).

Global and European regional assessment: Endangered (EN)
EU 27 regional assessment: Endangered (EN)

This European endemic jewel beetle species is very rare throughout its range with isolated populations and is known or suspected to be Extinct in several countries. Buprestis splendens is assessed as Endangered (EN B2ab(i,ii,iii,v)) both globally and for the EU27 Member States in view that its area of occupancy (AOO) is below 500 km², the habitat is threatened by unfavourable forest practices and the species is considered to be severely fragmented. The species is undergoing a continuing decline in the extent and quality of habitat, AOO, extent of occurrence (EOO), habitat quality and extent, and in the number of mature individuals.

This species is endemic to the European region. The general distribution of Buprestis splendens has been summarised by Obenberger (1927, 1930, 1941), Horion (1955) and Franz (1974). According to these references, this species was once scattered across Europe ranging from Russia to central and western Europe, and from south-eastern Europe to northern Europe: Sweden, Finland, Russia, Belarus, Ukraine, Poland, Czechia, Romania, Germany, Austria, Croatia, Bosnia-Herzegovina, Greece, and Spain. In these references, it is cited as imported with timber in the United Kingdom (Horion 1955, Franz 1974) and Denmark (Horion 1955, confirmed by Bílý 1982). Aside from these countries, it has been cited from Albania (Mühle 1980, Sakalian 2000), Hungary (Dorn 1942) and Slovenia (Dovrenik and Pirnat 2003). However, given that many reports of the species are very old, the status in each country needs careful consideration. Below, an assessment of the status per country is provided.

• Albania: cited from two sites, sites in 1959 and 1961, respectively (Mühle 1980, Sakalian 2000).
• Austria: historically known from four sites (Birnbacher 1872, Redtenbacher 1874, Holdhaus and Prossen 1901, Franz 1974, compiled in Paill and Zabransky 2005), with citations from 1871 to 1954. Considered extinct since 1954, it was rediscovered from 2001 onwards in a reduced area in Carinthia (Paill and Zabransky 2005, Aurenhammer and Komposch 2013, Aurenhammer et al. 2015).
• Belarus: no confirmed findings. An old, doubtful site from Vítebsk is given by Obenbergen (1941). This species is presumed to be present in the Belarus side of the Białowieża Primeval Forest, but with no data available (Alexandrowicz and Tsinkevich 2006).
• Bosnia and Herzegovina: three findings, two undated and another from 1916 (Obenberger 1927, Horion 1955). Presence mentioned by Obenberger (1941) and Mühle (1980) but no specific data provided.
• Bulgaria: presence possible but not confirmed (Sakalian and Langourov 2007).
• Croatia: an undated finding in Velebit-Stirovaca (Kaszab 1940, Horion 1955).
• Czechia: cited from Valtice (=Feldsberg) by Horion (1955) and Franz (1974). Nevertheless, this species is considered as introduced and extinct (more than 50 years without records) (Skorpik et al. 2011).
• Denmark: only records of specimens imported with timber (Bílý 1982).
• Finland: purported presence in Finland is probably due to a mistake with the Russian locality of Terijoki, cited by Horion (1955) as Finnish.
• Germany: aside of specimens imported with timber in Berlin, and one site in Könisberg (Obenbergen 1927), only general citations from northern Germany (Schmidt, 1937), Bavaria (Horion 1955, correcting the opinion of Kuntzen, 1937) and Säschichse Schweiz (Lorenz 2010). All citations are either prior to 1900 or undated.
• Greece: five sites, all undated, in N Greece, in Pindos Mountains, Olympus Mountain, and Trikala (Mühle 1981, Bílý 1982, Mühle et al. 2000). Mühle (1981) refers to recent findings and cites three references that are not listed in his reference list (Paulus 1979, Bëuerle et al. 1980, Brandl et al. 1981; these references have not been confirmed and are not listed in this assessment).
• Hungary: cited in two sites prior to 1940 (Stiller 1930, Kaszab 1940), but probably introduced with timber in one of them (Dorn 1942).
• Italy: cited in the Pollino National Park, from 1970 onwards, with recent (2018, 2019) records (Gobbi 1973, Izzillo 1989, Curletti 2006, Piazzini et al. 2020).
• Poland: records in two sites outside Białowieża in 1847 and 1955-56 (Siebold 1847, Balazy et al. 1974). General mentions in the Galitzia region (Obenberger 1941, Horion 1955, Franz 1974) do not refer to the Polish territory (Burakowski et al. 1985). There are repeated findings in the Białowieża National Park, considered as the only remaining Polish population (1916: Gutowski and Lugowoj 2000, 1917; Bischoff 1957, 1918; Obenberger 1927, 1921; Tenenbaum 1923, Gutowski and Lugowoj 2000, 1930, 1936; Gutowski and Logowoj 2000, 1937; Horion 1955, 1961, 1991; Gutowski and Lugowoj 2000, 2011, 2018; Gutowski et al. 2019).
• Romania: historical records in Baile Herculane (Dorn 1942 [which captured several individuals in 1938, 1939 and cites previous findings in this site by Obenberger (1927)], and Kaszab (1940), Szeben (Sibiu) (Kaszab 1940), Cindrel Mountains (1887: Petri 1912 Horion 1955), and recent (2000 onwards) findings in Cerna Valley National Park (Ruicanescu 2002, Cioruta et al. 2020).
• European Russia: cited from St. Petersburg (Obenberger 1927, 1941; Horion 1955, Franz 1974, Volkovich 2013). These citations could be due to the record of Buprestis splendens from Terijoki (now Repino) in 1866 (Horion 1955) which likely was a misidentification of the American Bupretis aurulenta Linnaeus, 1767 which has been unintentionally imported to several European harbour cities in 19^th century and disappeared soon after (M. Volkovich pers. comm. 2023). Tanasiychuk (1981) does not mention this species. Volkovich (2013) indicates a potential presence in the Leningrad Region of European Russia, but with a question mark.
• Slovenia: no specific sites mentioned. Considered extinct (Drovenik and Pirnat 2003) (last records prior to 1950; Vrezec et al. 2012).
• Spain: it is known from three sites, one with sight previous to 1953 (Cobos, 1953) and two with sights in 1956 and 1973, respectively (Verdugo, 2010). However, only the site cited by Cobos (1953) seems to have suitable habitat (Verdugo, 2010). The citation of Cádiz in 1956 is from a timber storage lot, so it could be imported (Verdugo Páez 1997).
• Ukraine: aside from old (1873, 1888, 1889, 1913, 1923) and recent sites around Kyiv (Obenberger 1927, Prokhorov 2010, Prokhorov and Vasilyeva 2015), old records are given for Cherkasy and Polesia region (Obenberger 1927, Prokhorov 2010) and Volhynia region (Obenberger 1941, Franz 1974).

Summarising, although B. splendens has been cited from a total of 18 countries in Europe, in none of them does the number of sites exceed eight (mostly one or two sites) and most of the citations are very old (previous to 1900), or old (previous to 1960). Only in five countries, are there confirmed sights after 2000: Austria, Italy, Poland, Romania and Ukraine. In all these countries, presence is limited to a single site or area.

This species is very rare across its European range, and its populations are severely fragmented and declining. It might be extinct in Albania, Bosnia and Herzegovina, Croatia, Hungary, Slovenia and Spain, and it is already extinct in Germany, Russia, Sweden and Ukraine (Prokhorov and Vasilyeva 2020). At present the species occurs only in a minor part of its original range with small and widely separated relict populations (Luce 1996).

Recent findings are limited to Schütt in Austria (Aurenhammer et al. 2015), Pollino National Park in Italy (Piazzini et al. 2020), Bialoweza Primeval Forest in Poland (Gutowski et al. 2019), Cerna Valley National Park in Romania (Cioruta et al. 2020). It may still be present in some sites in Greece (Mühle et al. 2000), but further confirmation is required.

This is an obligate saproxylic species. This species lives in relict old-growth forests of several coniferous species (Bílý, 1982): Pinus leucodermis (Izillo, 1989); P. nigra (P. Istrate pers. comm. 2009), P. sylvestris, P. laricio, P. pinaster, Larix decidua (Paill and Zabransky, 2005) and Picea abies (Gutowski and Lugowoj, 2000). Larval development takes place in the dry, dead wood of large diameter trunks (above 40 cm) and in the higher portion (10 m high or more) of the tree. Host trees have to be sun-exposed. This species rarely appears outside the upper part of the host trees; only when there is very old, dry wood lying on the ground, females can be seen lying eggs (Mühle et al. 2000). Adults fly in the warmer hours of the day during July and August (Paill and Zabransky, 2005).

The main overall threat is commercial and illegal logging, affecting age structures and tree density. Several subpopulations which are not subject to this threat are endangered by slow regrowth and are therefore vulnerable to a single threatening events such as fires or disturbances (heavy snow, windstorms) causing fall or dead or dying trees. Remaining populations can be threatened by the commercial collection of specimens. In Spain, suitable habitat with pines over 500 years old has been recently issued for timber harvest (A. Escudero pers. comm. 2022).

It is used for scientific research. This species is popular with beetle collectors and is found in international trade (Lipinska and Golab 2008). This illegal sale is posing a threat.

This species is listed on Appendix II of the Bern Convention and Annex II and IV of the EU Habitats Directive. This species is possibly Extinct in many countries and it is likely to struggle unless conditions change. Monitoring of the remaining sites and action plans based on this monitoring are recommended. Known populations with recent sights are within protected areas. In Romania, the only known population is well preserved in one protected area, which is difficult to access (P. Istrate pers. comm. 2009). In Italy, one of the known localities is in a national park. The species is included in the list of relict beetle species of primary central European forests (Eckelt et al. 2017).