Lichens from the Hudson Bay Lowlands: northeastern coastal regions of Wapusk National Park in Manitoba

Abstract

Lichens are an important component of most terrestrial ecosystems including the subarctic tundra. A narrow band of raised calcareous beach ridges on the Hudson Bay Lowlands supports subarctic tundra alternating with incipient wetlands. This is the first extensive study of lichens on these beach ridges providing valuable noteworthy additions to the flora of Manitoba and baseline data for a developing national park. This study reports 134 species of lichens and seven habitats containing lichen communities; three of the lichens are new reports for Manitoba. Trends in the data were explored among 932 specimens (134 species) and three characters, method of reproduction, growth form, and substratum. The sexually reproducing crustose lichens were found mainly in exposed microenvironments such as on rocks and driftwood. The vegetatively reproducing fruticose lichens grew in the more stable microenvironments such as among moss on the ground. The sexually and vegetatively reproducing foliose lichens, occurring in a wide range of microenvironments and substrata, were more suited to the exposed beach ridge habitats than were either the crustose or fruticose lichens alone. Genetically and symbiotically diverse populations of both algal and fungal partners, resulting from sexual reproduction, would be better equipped than vegetative populations to adapt to changing environments in these exposed habitats.Key words: distribution, floristic survey, growth form, life history strategies, raised beach ridge, reproduction.