The Osmoderma species complex is here treated as five separate species (barnabita, eremita, cristinae, italicum and lassallei), following Audisio et al. (2007, 2008). Distribution limits of these different forms remain poorly resolved, but for the purpose of these assessments, we follow the approximate distribution limits outlined in Audisio et al. (2007, 2008).

There is ongoing debate as to whether or not these forms constitute valid species, but for the purpose of this assessment, we are assessing each form separately as species, following Bezděk (2016).

This obligate saproxylic species is bound to veteran hollow broad-leaved trees, mainly beeches and oaks. It is assessed as Endangered, as it has a small extent of occurrence (EOO) of about 24,300 km² and potential area of occupancy (AOO) below 500 km². The population is considered severely fragmented considering the low dispersal ability of Osmoderma italicum. Its AOO and habitat extent and quality are declining as is, in general, the number of veteran trees with hollows. Moreover, regeneration of potentially suitable trees across the species' range is very slow with a progressing age gap: once the existing veteran trees have died, there will be no replacements in most areas. 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). Even if efforts are made now to replant appropriate tree species, there may still be a gap of about a century 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 and that includes introduction of artificial habitat (nesting boxes). Surveys and monitoring for this species are highly recommended and an action plan to be developed.

This species is endemic to southern mainland Italy, from central Campania to south Calabria (Bezděk 2016). It has been recorded from more than 30 sites (Stoch 2003, Mazzei and Brandmayr 2017, Piazzini et al. 2020). The EOO is about 24,300 km², and the potential AOO is estimated to be below 500 km² considering the potential habitat. There are more than ten locations with regard to the main threat.

Osmoderma italicum is a rare species. The population has not been quantitatively estimated but is considered to be small and declining. One or few adults were observed at each locality (e.g. Piazzini et al. 2020). The species is known to have disappeared from at least one locality. The species’ distribution and the European regional population is severely fragmented, since nearly every metapopulation is isolated from others, and the habitat gaps between strongly exceed the natural dispersal abilities of Osmoderma italicum. Therefore, it is likely that the specimens and gene flow between the individual, even rather closely situated metapopulations (e.g. separated by few kilometres only) is strongly limited.

The species is completely confined to natural habitats with old-growth broad-leaved forests, which are scarce within its distribution range and mainly present at 700-1,800 m. It is dependent on decaying heartwood in large old and hollowing trees; consequently, it is restricted to mature broad-leaved forests with old trees. The species is associated with chestnut, oak and beech trees.

This species is dependent on veteran hollow broad-leaved trees which are in continuous decline, including in the southern Apennine Peninsula. The main overall threat to this species is the decline in the extent and quality of the habitat caused by forest fires and logging. The restricted area of occupancy combines a limited population size with reduced habitat availability and, often, unsuitable local forest management. The illegal collection of specimens is also an ongoing threat which is not yet been evaluated (individual specimens of Osmoderma italicum appear on sale in Europe). The decreasing number of hollow veteran trees in forest and human-managed semiopen ecosystems is usually caused by large- or small-scale commercial management or abandoning the traditional practices of land use, e.g. grazing or pollarding trees. Increasing fragmentation of old-growth forests and the lack of connection amongst the habitat trees is likely an ongoing threat. Exploitation from forestry is often the key immediate issue, but equally damaging are long-term changes in tree age structure and an age-gap. The absence of potentially suitable trees directly surrounding the known trees inhabited by the species poses a nearly imminent threat of extinction for Osmoderma italicum, since no natural habitat is available to support both potential migration to new areas and expansion of the known isolated metapopulations.

It is used for scientific research and monitoring and appears in the international trade for commercial collecting.

The species is present in several nature conservation areas across its range and is included in the Annexes II and IV of the European Habitats Directive (Trizzino et al. 2013) and Annex II of the Bern Convention, under the Osmoderma eremita complex. It is listed as Endangered B2ab(i,ii,iii) in the Italian Red List of saproxylic beetles (Carpaneto et al. 2015).

Action is urgently needed to protect and appropriately manage existing veteran trees, such as resuming traditional pollarding, as well as to ensure that suitable habitat continuity to be available in future. For this reason, the use of artificial hollows (nesting boxes) is strongly recommended, also to increase the interconnectivity between the known metapopulations and provide habitat for expansion of the known metapopulations. Surveys and monitoring, as well as developing an action plan for this species are highly recommended.