Fungal assemblages in moss & lichen mats of boreal Manitoba
Robertson, Jason Scott
Fungal assemblages in mats of Cladonia mitis, C. rangferina, and Pleurozium schreberi in Manitoba were isolated and compared in July and September. Temporal changes in these fungal assemblages were seen over the two sampling periods. The fungal assemblages of C. mitis and C. rangiferina were significantly diffirent from those found in P. schreberi during both sampling periods. Isolation of fungi from C. mitis and C. rangiferina involved subsampling the lichens into upper and lower strata, which were also compared, revealing significant differences between the upper canopies and the lower bases of the lichen mats. Alternaria, Cladosporium, and Epicoccum) common epiphytes, were found to be associated with the upper canopies of C. mitis and C. rangiferina, while Mucor and Trichoderma, common soil fungi, were found associated with the bases of C. mitis and C. rangiferina. Soil litter sampling beneath mats of C. mitis and C. rangiferina revealed 11 fungal taxa found in the lichen mats that were not in the soil, 6 fungal taxa common to both lichen mats and soil litter beneath them, and 5 fungal taxa present only in the soil litter layers. Fungi isolated from C. amaurocraea, C. arbuscula, C. rangiferina, C. stellaris, C. uncialis, Evernia mesomorpha, Vulpicida pinastri, Stereocaulon alpinum, and Peltigera spp., revealed significant differences in fungal assemblages across the various lichens. Microhabitat determines fungal assemblages present on lichens. The most important factor of microhabitat seen was moisture. Amplification of a portion of nuclear small subunit ribosomal DNA (SSU rDNA) from the fungal partner of C. arbuscula revealed fragments of two different size classes in one region. One size class was suspended to contain an intron, while the other had no intron. Amplification of a separate region of SSU rDNA from the fungal partner of C. arbuscula revealed fingerprint banding patterns. Variation in banding patterns, as well as the presence or absence of the intron, was examined among samples both within and among 10 transects laid out on islands and lake shores over a 2 km area. Cluster analysis revealed no difference in variation within and among transects, indicating efficient gene flow over the area.