Integrating demography and fire management: an example from Florida scrub

Most research analyzing nonstructural carbohydrate (NSC) concentrations on resprouter species in fire-controlled ecosystems has concentrated on how NSC concentrations recover immediately after fire. However, we know little of the effect of long periods without fire on NSC concentrations. In order to assess the effect of different periods of time-since-fire on resprouter species, we studied carbohydrate concentrations (total [NSC], soluble sugars [SS] and nonsoluble sugars [NSS]) in five resprouting species with contrasting trends of abundance across a chronosequence of time-since-fire (0.5-40 yr) in Florida. Carbohydrate concentrations were highest in species with specialized reserve organs. [SS] was mainly explained by factors related to plant size, whereas time-since-fire was the main factor explaining [NSS]. Changes in [NSS] and [NSC] were correlated with the time-since-fire abundance patterns. Variation in [NSS] carbohydrates can be related to the structural development of vegetation, with only those species capable of accessing full light able to accumulate carbohydrates, whereas subordinate plants show reductions in the [NSS] carbohydrate fractions. In areas with long intervals between fires, this carbohydrate reduction could affect subsequent postfire resprouting vigour, although this remains to be confirmed.