Borders of Biodiversity: Life at the Edge of the World's Large Lakes

Abstract

The great lakes of the world represent a global heritage of surface freshwater and aquatic biodiversity. Species lists for 14 of the world's largest lakes reveal that 15% of the global biodiversity (the total number of species) of freshwater fishes, 9% of noninsect freshwater invertebrate biodiversity, and 2% of aquatic insect biodiversity live in this handful of lakes. The vast majority (more than 93%) of species inhabit the shallow, nearshore littoral zone, and 72% are completely restricted to the littoral zone, even though littoral habitats are a small fraction of total lake areas. Most fish species exploit benthic resources, which increases food web complexity. Moreover, littoral zones are both more negatively affected by human activity and less intensively studied than offshore waters. Conservation of the remarkable biodiversity and biotic integrity of large lakes will require better integration of littoral zones into our understanding of lake ecosystem functioning and focused efforts to alleviate human impacts along the shoreline.