Plant litter loss exacerbates drought influences on grasslands

Plant litter is known to affect soil, community, and ecosystem properties. However, we know little about the capacity of litter to modulate grassland responses to climate change. Using a 7-year litter removal experiment in a semiarid grassland, here we examined how litter removal interacts with consecutive droughts to affect soil environments, plant community composition, and ecosystem function. Litter loss exacerbates the negative impacts of drought on grasslands. Litter removal increased soil temperature but reduced soil moisture and nitrogen mineralization, which substantially increased the negative impacts of drought on primary productivity and the abundance of perennial rhizomatous graminoids. Moreover, complete litter removal shifted plant community composition from grass-dominated to forb-dominated, and reduced species and functional group asynchrony, resulting in lower ecosystem temporal stability. Our results suggest that ecological processes that lead to reduction in litter, s...

植物枯落物（plant litter）已知会对土壤、群落及生态系统特性产生影响。然而，目前我们对枯落物调节草地响应气候变化的能力仍知之甚少。本研究依托半干旱草地为期7年的枯落物移除实验，探究了枯落物移除与连续干旱的交互作用如何影响土壤环境、植物群落组成及生态系统功能。枯落物流失会加剧干旱对草地的负面影响。枯落物移除可提升土壤温度，但降低土壤含水量与氮矿化作用（nitrogen mineralization），进而大幅加剧干旱对草地初级生产力及多年生根茎状禾草（perennial rhizomatous graminoids）丰度的负面影响。此外，完全移除枯落物会使植物群落组成从禾草主导转变为杂类草主导，并降低物种与功能群的异步性，最终导致生态系统时间稳定性下降。本研究结果表明，导致枯落物减少的生态过程……