Calcareous fen vegetation and ecology and the disjunct Betula glandulosa in Southeastern Alaska

Abstract

Calcareous fens are rare within southeastern Alaska due to their unique geochemical setting, as are the plant communities produced by these environs. On a global scale these wetland types have been identified as valuable for their biodiversity and have received special protection. The first objective of this research was to characterize the floristics and hydrogeochemistry of a subset of calcareous fens on Chichagof Island in the northern Alexander Archipelago through intensive sampling within each site. Multivariate analyses were used to describe these wetland systems. The second objective of this study included investigating whether or not the disjunct Betula glandulosa (dwarf birch) population was restricted to its current site. B. glandulosa is a habitat generalist in its known range; however, it is found in only one location within the Alexander Archipelago. Germination and seedling transplant experiments were conducted that tested for the effects of site, competition, and the interaction between site and competition. In this manner a subset of calcareous fens in the region was described and abiotic parameters associated with B. glandulosa evaluated. Obtaining baseline information and understanding mechanisms behind these sources of regional biodiversity are important for monitoring purposes and detecting disturbance effects