Distribution and ecology of myxomycetes in high-latitude regions of the Northern Hemisphere

Aim The objective of this study was to analyse the data represented by 1976 specimens of myxomycetes collected in high-latitude regions of the Norther n Hemisphere to obtain information on the biogeographical relationships and patterns of occurrence of these organisms. The question of what factors li mit myxomycete distribution in high-latitude and cold-dominated regions was also addressed. Location Specimens of myxomycetes considered herein were collected from twe lve study areas in Iceland, northern Russia and Alaska, and Greenland. The vast majority of specimens were collected during the period of 1989-98. Methods Nine hundred and thirty-three specimens were recorded as field coll ections. In addition, 1043 specimens originated from moist chamber cultures prepared with 1453 substratum samples collected in the various study areas . From a database recording the type of substratum (wood, bark of living tr ees, litter or dung) for each specimen, patterns of substratum occurrence f or particular species of myxomycetes in high-latitude regions were determin ed. Results From the 150 species recorded for the twelve study areas, thirty-th ree were found to be widely distributed (recorded from at least five study areas), and only forty-one had a frequency of occurrence higher than 1% eit her in moist chambers or as field collections. These data were examined in an effort to identify possible factors limiting the distribution of myxomyc etes in high-latitude regions. Main conclusions Upon first inspection, the arctic and subArctic myxomycete biota seems to be a depauperate version of that of temperate and boreal re gions. However, a few species elsewhere recorded as rare but found to be fa irly common in this study indicate that a certain degree of distinctiveness exists in Arctic and subArctic myxomycetes.