This is a species of the Ampedus praeustus group. A genetic analysis based on the COI sequence shows no difference between the taxa A. praeustus, A. cardinalis and A. melonii (Rougerie et al. 2015). Another DNA investigation including more specimens and more DNA sequences is consistent with this first result and could indicates a synonymy between A. praeustus and A. cardinalis. However, divergent ecological and morphological characteristics argue for two distinct species (Vuataz et al. 2019). More investigations are needed.

Global and European regional assessment: Near Threatened (NT)
EU 27 regional assessment: Near Threatened (NT)

This species is listed as Near Threatened as this species is entirely dependent upon veteran trees as it inhabits decaying heartwood. This is a very specific habitat type which is already highly fragmented and subject to continuing significant decline. Although this species has a relatively wide distribution, its area of occupancy is small (AOO = 1,960 km²) as it is only found in veteran trees which are scattered across the landscape at very low densities. It is therefore close to qualifying as Vulnerable B2ab(iii). The rate of loss of veteran trees has not been quantified, but it is significant, and it may potentially exceed 20% in the next ten years (= three generations). Moreover, there is very little regeneration of suitable habitat across the species' range. Once the existing veteran trees have died, there will be no replacements in many areas. Even if efforts are made now to re-plant appropriate tree species, there may still be a gap during which time there would be very little suitable habitat available. Action is urgently needed to protect and appropriately manage existing veteran trees, as well as to ensure that suitable habitat continues to be available in future.

This species is distributed throughout Europe, ranging north into southern Scandinavia (mostly in Sweden) and south to Greece (Laibner 2000). In Ukraine it occurs in the central part of the forest-steppe zone, in Donetzkyi mountain-ridge. In Hungary there are very few records known from the hilly and lowland areas (Németh and Merkl 2009). In Latvia, this species is very localised and rare, insufficiently known (Barševskis 2005). It has also been confirmed in Estonia in 2021 (https://elurikkus.ee/). In Denmark it is present in the south. In France it is widespread but very rare and localised (Leseigneur 1972). Specimens indicated from Corsica belong to Ampedus praeustus var. melonii (Rougerie et al. 2015, J. Delnatte and H. Bouyon pers. comm. April 2023). In Switzerland, the species appears to be confined to the far west (Geneva region) and south (Ticino) (Chittaro and Blanc 2012, InfoFauna 2023). In Italy there are very few records, mainly from central and southern areas (including Sicily). Records from Sardinia certainly refers to A. praeustus var. melonii. In Britain, there are a small number of sites across lowland England, in the south-east, and the east and west Midlands.

This is a rare species across its European range, with a very fragmented distribution.

In the UK it is a rare species with a very fragmented range and about 15 isolated subpopulations known from modern records. There is little or no suggestion of a recent decline but there area a few sites with only old records, that have not been confirmed recently (Mendel and Clarke 1996).

In Ukraine it is very rare as it is only known from four specimens.

In Hungary it is very rare and the populations are small.

In Czechia and Slovakia it occurs sporadically in lowlands and highlands across the whole territory (Laibner 2000).

In Germany it occurs sporadically in lowlands across almost the whole territory (with the exception of the north-west), with about 15-20 known localities.

In Sweden there are more than 30 sites known from recent records (since 2000) in the southern part of the country.

In Denmark it is rare and local (Martin 1989).

In Switzerland, only three localities were known until 10 years ago (Chittaro and Blanc 2012). The use of window traps in old forests has enabled this number to triple over the last decade.

This is an obligate saproxylic species. An old growth species, heartwood decay specialist, typically found in very large old trees (diameter >35 cm). The typical habitat is the deciduous forest, but wooded pastures and parks are also very important.

The larvae develop in red-rotten heartwood of mostly Quercus, but also Castanea and more rarely Alnus, Tilia and Fraxinus. It occupies large hollows and smaller boughs as well as trunks.

There is a long larval period and adult dormancy; the adults remaining in their pupal cells from September until the following April, and they may normally be found under loose bark or in hollows from May to July (Alexander 2002). The larvae are predators, necrophagous (Dolin 1988) and potentially saproxylophagous (Ehnström and Axelsson 2002).

In Italy it is found in coniferous as well as broad-leaved trees.

In Hungary virtually all known records are from red-rotten wood of very old oaks

In France and Switzerland, larvae are found in the dry powder of red-rot in large trees of Quercus or Castanea.

English sites tend to be historic parklands and the trees are ancient open-grown examples, rather than forest situations (K.N.A. Alexander pers. comm. 2009).

In Czechia and Slovakia it lives in trunks of solitary old oaks in broad-leaf or mixed forests (Laibner 2000).

This species is restricted to veteran trees, so any activities which destroy these trees (e.g. cutting down avenues) is strongly detrimental to the species. The main overall threat is likely to be degradation or loss of habitat quality, involving structural changes in the tree populations arising from changing land use affecting age structures and tree density. Exploitation from forestry is often a key immediate issue, but equally damaging can be long-term changes towards canopy closure and loss of ancient trees as a result of non- or minimum-intervention management systems which all too often exclude grazing by large herbivores. Fragmentation and increasing isolation of beetle populations are also key factors.

Saproxylic Coleoptera tend to be popular with beetle collectors although trade is rarely an issue, the only exceptions being a few larger species of more dramatic form or colour.

Generally, the most important conservation measure to be recommended is the protection of large old trees of appropriate species (especially oaks, but also others), and habitat management to ensure that there is a constant or increasing supply of such veteran trees in future.

This species is listed as Vulnerable in the British Red Data Book (Shirt 1987), and as Near Threatened in Sweden (SLU 2023).

In the UK, wood pasture and parkland are a priority habitat that is under the Government Biodiversity Action Plan. Also other conservation measures in place cover general management guidelines (K.N.A. Alexander pers. comm. 2009).

The species is present in protected areas (e.g. Hungary).