Threatened forest species (4.8)

Grey snail (Bulgarica cana) is an extremely endangered species in Finland.

Monitoring of threatened²⁹ species yields information about changes in forest ecosystems. It is estimated that there are about 45,000 species living in Finland, about half of which have their habitat in the forest. In the latest evaluation from 2010 21,400 species were assessed. About one tenth of them – 2,247 species – were classified as threatened. This percentage has not changed significantly from the previous evaluation.

Forest is the primary habitat for 814 threatened species (36% of the total). Of the threatened forest species, 82% live in herbrich forests and old-growth heathland forests. The taxonomic groups with the greatest number of threatened forest species are invertebrates and fungi. Changes in the forest habitat, especially the reduction in decaying wood, is the most common threat for forest species.

The Finnish evaluation of threatened species is the among of the most extensive assessments in the world. Similar evaluations have been made only in Sweden and Norway. The evaluation of 2010 made – for the second time – use of the international classification of threatened species, the IUCN classification. Based on the two consecutive, comparable evaluations carried out between a period of 10 years, comparison of development was possible for the first time.

The rate of decline of certain forest species has slowed down in Finland, or in some cases even stopped since the 1990s, although it has not been possible to halt the decline in the forest species overall. Actual taxonomic changes in the number of threatened forest species between 2000 and 2010 demonstrate that positive changes in threatened status had occurred in 81 species. About half of these are beetles, many of which have benefited from retention trees at harvesting sites, particularly aspen.

By contrast, 108 species whose primary habitat is the forest have experienced a deterioration. The trend was particularly significant for lichen. The classification of 34 species of lichen was upgraded, and none were downgraded. Similar negative trends were found among species of butterfly, beetle and hymenoptera. Factors in forest use constitute the principal cause in the decline for 606 species, or 74% of all threatened forest species. Forest management measures may have reduced the number of certain habitat types such as old-growth forests in their natural state while also weakening the quality of some forest habitats.

The number of threatened species is growing the fastest in traditional rural biotopes, of which wooded pastures and grazed forests are wooded land.

Table 4.8. Number of threatened forest and mire species

Source: Rassi, P., Hyvärinen, E., Juslén, A. & Mannerkoski, I. (eds.) 2010: The 2010 Red List of Finnish Species. Ympäristöministeriö & Suomen ympäristökeskus, Helsinki. 685 p.; Rassi, P., Alanen, A., Kanerva, T. & Mannerkoski, I. (eds.) 2001. Suomen lajien uhanalaisuus 2000. [Endangered species in Finland 2000]

Links

• The 2010 Red List of Finnish Species

29 Endangerment refers to the probability of the species becoming extinct. Anthropogenic and non-anthropogenic causes of endangerment are not distinguished in the assessment of endangerment. All threatened species are classified as critically endangered, vulnerable and endangered.