Antarctic Marine Animal Forests: Three-Dimensional Communities in Southern Ocean Ecosystems

Abstract

Both Southern Ocean and terrestrial systems contain three-dimensional biotic components that are key in shaping and defining their respective ecosystems and communities. Antarctic suspension-feeding communities, which inhabit the shelf of the Southern Ocean, resemble ``Terrestrial Vegetation Forests'' (TVF) or shrublands and support the concept of ``Antarctic Marine Animal Forests'' (AMAF). They comprise mostly sessile animals, provide microniches for an associated mobile fauna, and are fragmented and regionally mixed with other communities. On land, only high mountains and very dry regions are unsuitable for TVF, analogous to the virtual absence of AMAF from the deep sea (>1000 m). Besides fundamental differences between these systems in energy flow and other ecological drivers such as light requirements and dispersal opportunities, both ``forests'' experience similar disturbances, which impact ecosystem dynamics and diversity in similar ways. While land use affects and reduces terrestrial forests, climate change and fishing impacts are the most serious threats to the Southern Ocean ecosystem. Research priorities for a better understanding of ``Antarctic Marine Animal Forests'' demand (1) mapping biotic communities and their structural and functional diversity, especially in terms of hot and cold spots; (2) understanding ecological function, including ecosystem productivity and dynamics; (3) cross-system comparison to identify generality or uniqueness in ecosystem structure and dynamics; and (4) implication of existing and new research approaches and conservation strategies.