Coeloglossum viride subsp. islandicum in Norway - distribution, ecology and present situation.
Coeloglossum viride subsp. islandicum is known from the British Isles, The Faroe Islands and Iceland. In Norway, the distribution is restricted to Rogaland county, in the southwest. The taxon has been known in Norway for about ten years but is still not very well understood. The systematic status of the taxon is still discussed, but in any case this is an isolated group of populations being phenotypically clearly deviant and growing in an unusual habitat, which justifies it being viewed as a separate unit for protection and management purposes. The present study monitored the subspecies during a period of five years. Three metapopulations in Rogaland are known but only one is known to be still present. Distinct variations in the number of plants and the local distribution seems to be typical patterns. During the five years of monitoring the number of plants in the present metapopulation varied between c. 300 and 2000. Changing number of above-ground plants is considered to be part of the natural variation, which can partly be due to variations in weather from one year to another, partly also an aggregate effect of each plant's and population's life cycles. Seed production is often abundant and periods of above-ground no-show may represent the two or three years immediately following germination, while seedlings are still in the leafless subterranean stage of their life cycle. The populations are threatened by expanding alien tree species and shrubs.