Severe fragmentation of ocean habitats is predicted to occur due to the loss or movement of a group of plants and animals that form habitat for others, called foundation species. Loss of foundation species will result in the loss of hundreds of other species, from algae to predators that depend on these structure-forming organisms for habitat, shelter, and food.1 Foundation species, such as corals, sea grasses, and kelp, form distinct habitats by providing shelter and food for numerous organisms. Corals face numerous threats including bleaching and disease due to increased temperature,2 dissolution from increasing ocean pH,3 and inundation from sea level rise. Sea grass and kelp forest habitats are faced with critical losses due to sea level rise, changes in nutrient delivery, and increased sedimentation from altered river flow.
Many important coastal habitats that provide benefits to human society and the environment alike are also highly likely to experience severe declines. Estuaries, marshes and mangroves are vital nursery habitats for many commercially important species, perform important sediment and water filtration functions and provide coastal protection from storms. The size of these habitats has already been reduced due to the expansion of human activities in the coastal zone. Further constriction of available space as a result of coastal development and increased erosion may result in the complete disappearance of these essential coastal habitats.
Finally, substantial loss of sea ice habitat in polar regions due to rising ocean temperature will negatively affect many organisms including crustaceans, fish and marine mammals.4,5 Algae, that grow on the underside of sea ice and support polar food webs, will decrease as the ice habitat shrinks. In the Arctic, loss of sea ice has already had dramatic impacts on community structure from primary producers (e.g. copepods) to top predators (e.g. polar bears).