XVI International Botanical Congess

During a recent survey for non-indigenous species in Port Valdez, 113 species of seaweeds, seagrasses, and marine lichens were found to occur in the heavily trafficked fjord. A biogeographic analysis of the species revealed few obvious introductions. Instead, half of the species were found to be limited to the North Pacific and native to this region while the other half were more widely distributed and cryptic in origin. Of the cryptogenic forms, 23 occurred circumboreally and 33 had ranges ex- tending into the Southern Hemisphere. The more narrowly distributed species consisted primarily of red algae while the widespread cryptogenic species were dominated by green and then brown algae. These distribution patterns appear to reflect the dispersal capabilities of the species, the taxonomic resolution of the algal groups, and the young age of the Port Valdez flora.