World distribution: Pannaria ignobilis is a mainly European species with a Mediterranean-Atlantic distribution; it is also known from a few localities in NW Africa (Jørgensen 1978). Its distribution ranges from Greece to Portugal in the Mediterranean area, further north it is known from some scattered localities in the central Highlands of Scotland and from coastal parts of Norway
Ecology: Results. Indicated substrates include Populus tremula (37 records), Sorbus aucuparia (23), Fraxinus excelsior (9), Salix caprea (5), Quercus spp. (5), Ulmus glabra (4), Acer spp. (1) and, Tilia cordata (1). Habitats are recorded at 54 localities, and include shady spruce forest (26), broadleaved deciduous forest (9), coastal pine forest with Populus tremula (7), mixed deciduous forest with Betula sp., Populus tremula, and Sorbus aucuparia (6), oak forest (3), an old meadow with pollarded Fraxinus excelsior (1), a Picea plantation with Populus tremula and Sorbus aucuparia (1), a and mixed coniferous/deciduous forest (1). Discussion. According to Jørgensen (1978), Pannaria ignobilis is an exclusively corticolous species which is mentioned as a member of the 'Lobarion'. However, it is often found in more open and drier habitats than other Pannaria species, e.g. on solitary trees. In the southernmost part of its Norwegian distribution area it seems to prefer Quercus spp. in sheltered habitats. In western Norway, it prefers Fraxinus excelsior and Populus tremula, often in rather open habitats. Further north P. tremula is the main substrate, but in central Norway there is a change in ecology towards more shady habitats, often Sorbus aucuparia in dark spruce forests. The most strongly shaded habitats are avoided, however
Threats: Results. Recorded threats were forestry (35), lack of substrate due to grazing by elk (4), air pollution (1), and road construction (1). Discussion. Even if logging is considered the most serious threat to this species, it seems that P. ignobilis is able to tolerate some selective logging, at least in humid areas when sufficient substrate is available. It seems important that extreme shading from new forest generations is prevented. Over parts of Trøndelag young Sorbus aucuparia and other suitable host trees are almost completely lacking due to heavy elk grazing
Status: Twenty-two old localities have been investigated. The species was found in 7, apparently extinct in 9, and of uncertain status in 6. Thirty-eight new localities were discovered, including some large, vital populations. Four localities (1348, 1461, 1650, 1653) are within nature reserves, but all of these contain small populations