The Importance of Long-Term Studies of Ecosystem Reassembly after the Eruption of the Kasatochi Island Volcano

Abstract

Kasatochi Island is a small volcanic island in the central Aleutian Islands that erupted on 7 August 2008. An interdisciplinary team visited the island and its vicinity in the summer of 2009 to describe the immediate consequences of the eruptions on terrestrial, coastal, and benthic communities. The initial effects of the eruptions on soils, oceanic waters, benthic terrain, terrestrial plants, land birds, shore birds, nesting sea birds, arthropods, marine algae, and marine invertebrates were described. This overview summarizes the conventional understanding of mechanisms that drive the reassembly of devastated ecosystems and shows how studies of Kasatochi Island may enhance our understanding of succession. The presence of residual soils and low mortality among sea birds will hasten early recovery, but significant erosion (removal of tephra and marine sediments) must occur to permit a return to a fully functional ecosystem. Long-distance dispersal over seawater will be needed to replenish the plant communities. While scavenger arthropods survived, dispersal will be needed to generate complete insect communities. Land birds were killed and their habitats destroyed, so their re-colonization awaits vegetation development. Ecosystem recovery will be facilitated by allochthonous inputs of nutrients and by plant establishment. Monitoring how the biota returns to a new equilibrium and comparisons to adjacent islands will allow tests of assembly and biogeographic theory and further our understanding of terrestrial-marine interactions. The study of Kasatochi Island’s recovery will produce a valuable story of ecosystem reassembly.