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Artificial substrata colonized by freshwater lichens

2005; Cambridge University Press; Volume: 37; Issue: 4 Linguagem: Inglês

10.1017/s0024282905014672

1096-1135

Christine Keller,

Biocrusts and Microbial Ecology

Small clay cubes, fired at different temperatures and mounted with nylon touch and close fastener (Velcro ® ) on acrylic glass plates, were used in an experimental design to study colonization of artificial substrata by lichens. The cubes were exposed in alpine streams for either 5–7 y at five different sites in the Swiss Alps: Flüelatal (three sites) and Brigels (Canton of Graubünden), and Eggerberg (Canton of Valais). Only a few cubes were lost, except at two sites, where complete plates were lost – due to the strong water current and, probably, trampling by cattle. After 3 y, freshwater lichens had grown at three sites. At the most elevated site, colonization was observed after 4 y; at one site no lichen growth was recorded. The first colonizers of the new substrata were the locally most common species. Freshwater lichens preferred the surfaces of clay cubes fired at lower temperature, whereas exposed pieces of local rocks were less frequently colonized. Improvements in the experimental design are suggested.