Belowground starch consumption after recurrent severe disturbance in three resprouter species of the genusErica

Abstract

It is generally assumed that belowground starch reserves are consumed partially and gradually after successive resprouting events in resprouter woody plants. We have explored the aboveground (biomass) and belowground (root starch) response of three species of Erica, Erica australis L., Erica scoparia L., and Erica arborea L., after different histories of disturbance intensity to test the existence of a gradual decrease in (i) the final biomass of the aboveground regrowth and (ii) the relative amount of root starch across increasing levels of disturbance frequency. Increasing clipping frequency produced a progressive reduction in the final regrowth in the three species. By contrast, root starch levels dropped markedly in plants of all clipping treatments when compared with root starch of unclipped plants, but significant differences were not detected among clipping frequencies. This pattern was consistent across the three species of Erica. This study highlights a crucial role of belowground (root) starch reserves for postdisturbance regrowth in resprouter species of Erica. It also shows a consistent pattern of rapid, not conservative, consumption of starch reserves after the complete removal of the aboveground part, nearly irrespective of the previous history of disturbance frequency.