Kalkområdene i Snåsa og Steinkjer, Nord-Trøndelag – oaser for sjeldne karplanter, moser, lav og sopp

Abstract

The calcareous areas of Snåsa and Steinkjer municipalities have for a long time been well known for their rare vascular plants including several redlisted orchids such as Cypripedium calceolus, Epipogium aphyllum and Ophrys insectifera. However, the diversity of bryophytes, lichens and fungi in the same areas has until recently been much less known. This paper summarizes 10 years of floristic field work in calcareous coniferous forests in the Snåsa and Steinkjer municipalities. Of particular interest are the high number of mycorrhizal fungi recorded close to hotspot areas of orchids, including species of Cortinarius, Hygrophorus, Ramaria and Sarcodon. A number of crustose lichen specialists of calcareous rock were also recorded, many of which are rarely collected. Petractis clausa is a characteristic member of this group. The bryophyte flora is diverse with several nationally scarce species. Especially bryophytes of calcareous rock walls, in both spruce and pine forest, include many rare and red listed species. A mixture of phytogeographic elements are present in the area including both southern/southeastern, northern and western species. Several southern species are probably relict populations from the warmer period after the last glaciation. Some of the forest types are unique for the Scandinavian peninsula, like certain types of moist calcareous spruce forests on shallow soils.