Diatoms define a novel freshwater biogeography of the Antarctic

<p><span class="fontstyle0">Terrestrial biota in the Antarctic are more globally distinct and highly structured</span><br> <span class="fontstyle0">biogeographically than previously believed, but information on biogeographic patterns</span><br> <span class="fontstyle0">and endemism in freshwater communities is largely lacking. We studied biogeographic</span><br> <span class="fontstyle0">patterns of Antarctic freshwater diatoms based on the analysis of species occurrences in a</span><br> <span class="fontstyle0">dataset of 439 lakes spread across the Antarctic realm. Highly distinct diatom floras, both</span><br> <span class="fontstyle0">in terms of composition and richness, characterize Continental Antarctica, Maritime</span><br> <span class="fontstyle0">Antarctica and the sub-Antarctic islands, with marked biogeographic provincialism in</span><br> <span class="fontstyle0">each region. A total of 44% of all species is estimated to be endemic to the Antarctic, and</span><br> <span class="fontstyle0">most of them are confined to a single biogeographic region. The level of endemism</span><br> <span class="fontstyle0">significantly increases with increasing latitude and geographic isolation. Our results have</span><br> <span class="fontstyle0">implications for conservation planning, and suggest that successful dispersal of</span><br> <span class="fontstyle0">freshwater diatoms to and within the Antarctic is limited, fostering the evolution of</span><br> <span class="fontstyle0">highly endemic diatom floras</span><br>  </p>