Phenological mismatches between above- and belowground plant responses to climate warming

Abstract

Climate warming is changing the aboveground phenology of plants around the world. However, the effects of warming on the belowground phenology of plants remain relatively under-investigated, even though roots play a vital role in carbon cycling. Here we synthesize 88 published studies to show a phenological mismatch between above- and belowground plant responses to climate warming. For herbaceous plants, warming advanced both the start and end of aboveground growing season, resulting in an unchanged growing season length. In contrast, belowground phenophases (the start, end and length of the growing season) of herbaceous plants remained unchanged. For woody plants, climate warming did not affect any aboveground phenophases but extended their belowground growing season. Mismatches between above- and belowground phenology will strongly influence biomass allocation in plants, implying that terrestrial carbon cycling models based exclusively on aboveground responses are inaccurate. The work highlights an urgent need for future research of under-represented belowground phenological changes.