Effect of experimentally induced climate change on the seed bank of a Mediterranean shrubland

Abstract

AbstractQuestionsWe studied the soil seed bank under field‐simulated climate change conditions and addressed the following questions: Is the effect of climate change on seed banks more evident in areas without vegetation? Are short‐lived species more sensitive to this directional climate change than long‐lived species?LocationA Mediterranean shrubland in the Garraf Natural Park, NE Spain.MethodsDirectional climate change was induced through manipulating temperature and rainfall over almost 9 yr. Soil seed banks were assessed using the seedling emergence method.ResultsUnder drought and warming treatments, the total number of germinating seeds decreased by 47% and 43%, respectively, in non‐vegetated areas. In contrast, no effect was found for areas with vegetation cover. Reduced seed bank density was particularly pronounced for short‐lived species (therophytes plus hemicryptophytes), which dropped by 60% and 69%, respectively, in the drought and warming treatments in open areas, while no significant changes were observed under vegetation. In non‐vegetated areas, the reduction in seed bank density was similar in all species. In contrast, a shift in the relative abundance of seed bank species was apparent under shrub canopies.ConclusionsAs experimental climatic manipulations of Mediterranean shrublands demonstrate a trend towards an increase in open areas under drought conditions, a decrease in the seed bank of short‐lived species in these areas may potentially result in a positive feedback that would accentuate the loss of vegetation cover under predicted future climate conditions.