The bog climax hypothesis: fossil arthropod and stratigraphic evidence in peat sections from southeast Alaska, USA

The hypothesis that bogs are climax (structurally and compositionally stable) communities has been proposed for several large regions including southeast Alaska. A logical consequence of the bog climax is the hypothesis that, where there is infrequent large‐scale physical disturbance, landscape‐level changes from early successional woodland to late successional peatland should have occurred during the Holocene. This hypothesis is tested in southeast Alaska using analyses of fossil arthropods and site stratigraphy, as well as a review of the ecological literature. Results indicate at least three major landscape types have dominated since deglaciation: deciduous woodland (about 9000 to 6000 yr BP), coniferous woodland (about 6000 to 3000 yr BP), and peatland (about 3000 yr BP to present). Other paleoecological and ecological studies from around the region provide evidence for directional changes, both past and present, from woodland to peatland. Furthermore, there is no clear evidence for peatland to woodland transitions in the absence of large‐scale disturbance. These results suggest that the bog climax hypothesis deserves a more careful examination by ecologists studying succession.