Holocene comment and reply

McClymont et al. ( The Holocene 18 (2008) 991—1002) present data on several environmental proxies to explore the disappearance of Sphagnum imbricatum from a peat bog in northern England, Wales and Ireland, respectively. McClymont et al. used their results to argue that a combination of rapid water-table rise and increased aeolian nutrient input from surrounding (agricultural) areas may have caused the disappearance of S. imbricatum from European raised bogs. The paper contributes to a growing body of literature focusing on the ‘abrupt’ decline of S. imbricatum (S. austinii) AD 1000—1700. From the literature it becomes apparent that determining the exact mechanism for the decline of S. imbricatum ( S. austinii) is difficult. Hence, many potential mechanisms have been suggested, amongst which increased wetness, increased interspecific competition, local burning and increased nutrient input are just a few examples. Although we do not comment on the quality of the science, there are a few things to be considered in order to get a complete picture.