Relict forest species (categories 1 and 2) are defined as species that meet the following criteria in Central Europe.

• they are closely linked to the continuity of old stands and habitat traditions,
• they have high requirements for the quality and quantity of dead wood,
• current populations in cultivated forests in Central Europe are declining or becoming extinct.

Within this group, we distinguish between relict species of old-growth forests sensu stricto (= category 1) and sensu lato (= category 2). Category 1 species are now limited to a few remnants of natural forests and require additional conditions, resources and structures, such as extensive forest landscapes, rare wood-dwelling fungi, large-sized dead wood, high tree age, heliophilous conditions, long-term maintenance and late succession stages of dead wood in stands. Category 1 species are therefore extremely rare. Category 2 species meet the same defined criteria but may also occur in production forests if their specific habitat requirements are met.

The International Union for Conservation of Nature (IUCN) Red List of Threatened Species is also known as the IUCN Red List or Red Book.

IUCN threat levels:

• Extinct (EX): there is no doubt that the species no longer exists. A species is classified in this category if no living representative has been found in the area for more than 50 years (but the species was previously known to occur there).
• Extinct in the wild (EW): the species survives only in captivity, cultivation and/or outside its original range, as assumed after exhaustive surveys. A species is classified in this category if no living representative has been found in the area for more than 50 years (but the species was previously known to occur there).
• Critically endangered (CR): species facing imminent extinction, surviving only in a few locations with a small number of individuals. The species meets any of the criteria A to E for critically endangered and is presumed to face an extremely high risk of extinction in the wild.
• Endangered (EN): a species that is relatively numerous but whose numbers have been declining recently. The species meets any of the criteria A to E for endangered and is considered to be facing a very high risk of extinction in the wild.
• Vulnerable (VU): a species facing an increased risk of extinction in the medium term if conditions do not change. The species meets any of the criteria A to E for vulnerable and is believed to face a high risk of extinction in the wild.
• Near Threatened (NT): A species that may be threatened with extinction in the near future but does not yet meet the criteria for Vulnerable, Endangered or Critically Endangered.
• Least Concern (LC): a species for which there is very little or no concern about its risk of extinction.
• Data Deficient (DD): a species is classified as "data deficient" if there is insufficient information available to make a direct or indirect assessment of its risk of extinction based on its distribution and/or population status.
  
  

• f - Fresh wood inhabitants
  Fresh wood colonisers: vivixylophagous and zoophagous colonisers of living wood parts. Depending on the moisture content of the wood, colonisation of the substrate takes place up to approximately one year after the wood has died.
• a - inhabitants of old wood
  Old wood colonisers: saproxylic and zoophagous colonisers of wood that died a long time ago (old wood, decaying wood, wood humus).
• m - inhabitants of mulm cavities
  Colonisers of mulm cavities: xylodetritophages and zoophages colonising wood material decomposed into mulm inside still solid wood structures (mulm cavities, heart rot, etc. in broken and dead trees).
• p - wood-decaying fungi
  Wood fungus colonisers: mycetophagous colonisers of mouldy parts of wood or exclusively on fruiting bodies of fungi growing on wood.
• s - xylophagous special biological systems
  Xylobiont specialised organisms: succulent, necrophagous, coprophagous, saprophagous, nidicolous, pollenophagous, etc. Colonisers of wood structures (animals feeding on tree sap, commensals, parasites, animals feeding on chitin, carcasses and droppings in the nests and tunnels of other wood-destroying insects, etc.), colonisers of tree phytoteloms, etc.
   

Indicates whether the taxon occurs in the Czech Republic. The data corresponds to the status as of January 2026.
 

The table of primeval forest relics on this page is primarily based on the publication by A. Eclekt et al: "Primeval forest relict beetles" of Central Europe: a set of 168 umbrella species for the protection of primeval forest remnants, Journal of Insect Conservation, 2017. Data from the original table has been supplemented with data from other sources:

• European Red List of Saproxylic Beetles 2018
• European IUCN Red List (January 2025)
• J. Schmidl: Ökologische Gilden xylobionter Käfer Deutschlands, Naturschutz und Landschaftsplanung 36, (7), 2004.
• Zumr V., Remeš J.:Saproxyličtí brouci jako indikátor biodiverzity lesů a vliv lesnického managementu na jejich rozhodující životní atributy: review, 2020