World distribution: Ramalina dilacerata is a circumboreal species, occurring in North America, Asia, and Europe (Ahti 1964, Krog 1968, Yoshimura 1974, Ahti 1977a, Krog & James 1977). The European distribution includes Fennoscandia, the Central European mountains, and Russia (Ahlner 1948, Krog & James 1977). The main Fennoscandian occurrences of this species are in the eastern parts of Sweden, particularly along the Gulf of Bothnia, and in Finland where it is more widespread (Ahlner 1948, Krog & James 1977)
Ecology: Results. Indicated substrates (recorded at 9 localities) were Picea abies (4), Salix sp. (3), Sorbus aucuparia (3), Alnus incana (2), Salix caprea (2), Populus tremula (1), Prunus padus (1), and worked timber on an old bridge (1). Habitat (recorded at 8 localities) were Alnus forest (3), spruce forest (2), pine forest (1), birch forest (1), and mixed deciduous forest (1). The species grew near lakes or rivers in all localities, and at least four of the localities are situated in narrow canyons. Among associated lichens in the locality with highest abundance of R. dilacerata (38) were Evernia divaricata, Ramalina obtusata, and R. sinensis. Discussion. Ramalina dilacerata has similar substrate preferences in other parts of the world, being reported from deciduous trees, mainly Alnus incana, Populus tremula and Betula, as well as from twigs of conifers, mainly Picea spp., and occasionally on lignum (Ahlner 1948, Ahti 1964, Barkman 1958a, Krog & James 1977, Bird et al. 1980, Gowan & Brodo 1988, Goward & Ahti 1992). According to Ahlner (1948), the species often grows on the lowermost, dead twigs of Picea abies. The most frequent habitat in Norway is boreal, moist Alnus incana forests bordering rivers, usually in canyons. The species requires well-lit sites (Goward & Ahti 1992) near running water (Ahlner 1948, Bird et al. 1980, Gowan & Brodo 1988, Karström 1992b). Most localities seem to be fire-free refugia, and the species may be an indicator of long canopy continuity (Karström 1992a, Bredesen et al. 1993). Rare lichens like Chaenothecopsis viridialba, Cyphelium karelicum, Hypogymnia bitteri, Ramalina thrausta, and Sclerophora coniophaea are often recorded at its localities in northern Sweden (Karström 1992b). Along the shores of the Gulf of Bothnia, Ramalina dilacerata is characteristically associated with R. roesleri and Evernia mesomorpha (Räsänen 1927, Ahlner 1948). In Troms (2381), the species occurs together with several species which are rare in North Norway, e.g. Evernia prunastri and Usnea filipendula (Elvebakk 1993)
Threats: Results. Recorded threats are logging (3), hydroelectric power development (3), construction (2), pollution (1), and cultivation (1). Discussion. The populations are small in most localities. The largest population is situated within Liadalen forest reserve (38), where the species is relatively common along the river Vinstra. Elsewhere it only grows on one to five trees per locality. Logging appears to be the main threat. Since R. dilacerata grows close to running water, hydroelectric power development is a possible threat
Status: Six old localities were visited during the project. The species was found at 3 sites, apparently extinct from 2, and of uncertain status in 1. Three new localities were discovered. Three localities are situated within protected areas (36, 37, 38)
Specimens in other herbaria, litterature, etc.