Impacts of extreme precipitation and seasonal changes in precipitation on plants

[摘要] The global hydrological cycle is predicted to become more intense in futureclimates, with both larger precipitation events and longer times betweenevents in some regions. Redistribution of precipitation may occur bothwithin and across seasons, and the resulting wide fluctuations in soil watercontent (SWC) may dramatically affect plants. Though these responses remainpoorly understood, recent research in this emerging field suggests theeffects of redistributed precipitation may differ from predictions based onprevious drought studies. We review available studies on both extreme precipitation(redistribution within seasons) and seasonal changes in precipitation (redistribution across seasons) ongrasslands and forests.

Extreme precipitation differentially affected above-ground net primaryproductivity (ANPP), depending on whether extreme precipitation led toincreased or decreased SWC, which differed based on thecurrent precipitation and aridity index of the site. Specifically, studiesto date reported that extreme precipitation decreased ANPP in mesic sites,but, conversely, increased ANPP in xeric sites, suggesting that plant-available water is a key factor driving responses to extreme precipitation.Similarly, the effects of seasonal changes in precipitation on ANPP,phenology, and leaf and fruit development varied with the effect on SWC.Reductions in spring or summer generally had negative effects on plants, associatedwith reduced SWC, while subsequent reductions in autumn or winter had littleeffect on SWC or plants. Similarly, increased summer precipitation had a more dramaticimpact on plants than winter increases in precipitation.

The patterns of response suggest xeric biomes may respond positively toextreme precipitation, while comparatively mesic biomes may be more likelyto be negatively affected. Moreover, seasonal changes in precipitation duringwarm or dry seasons may have larger effects than changes during cool or wetseasons. Accordingly, responses to redistributed precipitation will involvea complex interplay between plant-available water, plant functional type andresultant influences on plant phenology, growth and water relations. These results highlightthe need for experiments across a range of soil types and plant functional types,critical for predicting future vegetation responses to future climates.

[学科分类] 地球化学与岩石