Threatened Plant, Animal, and Fungus Species in Swedish Forests: Distribution and Habitat Associations

Swedish forestry is among the most technically developed in the world; a large part of all forest is used for commercial forestry, which has had a large impact on the structure and function of forest ecosystems. We have compiled present knowledge on the distribution and habitat associations of 1487 threatened forest species in Sweden, made an attempt to identify structures and elements that are critical for their occurrence and suggest guidelines for the maintenance of threatened forest species. Habitat associations and distribution patterns of the threatened species were roughly the same for all organism groups. A significantly higher proportion of the 1487 species in all organism groups (cryptogams, vascular plants, invertebrates, and vertebrates) were found in the south (temperate/hemiboreal region) than in the north (hemiarctic/boreal region) of Sweden. For each organism group, the southern deciduous forest contained the most threatened species. Coniferous forests and other deciduous forests were also relatively species‐rich, while deforested areas and scrub areas were the least species‐rich habitats for the studied species. Most groups were dependent on specific elements in the habitat, which all were characteristic of old forests. Old living trees (especially deciduous trees) were critical for vertebrates, invertebrates, and cryptogams. Logs were critical for invertebrates and cryptogams. Snags were especially important for invertebrates and to some extent for vertebrates and cryptogams. Vascular plants were more dependent on abiotic factors and stand/site‐related factors, such as forest density and forest age, than were the other groups. All groups, however, were largely dependent on old forests or habitat elements associated with old forests. The threatened populations of forest species of international importance (supposed endemics to Scandinavia or with more than 10% of the European population in Sweden) were found to a relatively large extent in coniferous forests in the north of Sweden, while the other threatened species were more restricted to deciduous forests in the south.