College of Geography and Environment Science, Northwest Normal University, Lanzhou, China.
Key Laboratory of Resource Environment and Sustainable Development of Oasis, Northwest Normal University, Lanzhou, Gansu Province, China.
Plant Biol (Stuttg). 2024 Apr;26(3):378-389. doi: 10.1111/plb.13622. Epub 2024 Mar 5.
Precipitation pattern changes may affect plant biodiversity, which could impact ecosystem stability. However, the effects of changes in precipitation regime on ecosystem stability and their potential mechanisms are still unclear. We conducted a 3-year field manipulation experiment with five precipitation treatments (-40%, -20%, 0% (CK), +20% and +40% of ambient growing season precipitation) in a semi-arid desert grassland to examine the effects of precipitation alterations on functional group stability, species asynchrony, and diversity, and the underlying mchanisms of ecosystem stability using structural equation modelling. Alterations in precipitation had different effects on community biomass and functional group biomass. Moreover, ecosystem stability was mainly driven by forb stability (path coefficient = 0.79). Changes in precipitation had significant effects on soil dissolved inorganic N (P < 0.01) further affecting ecosystem stability through species asynchrony (path coefficient = 0.25). Dwarf shrubs had a stabilizing effect on ecosystem stability (path coefficient = 0.32), mainly via deep roots. Ecosystem stability tended to be lower in the -40% (4.72) and +40% (2.74) precipitation treatments. The common reduction in species asynchrony and stability of forb and dwarf shrub functional groups resulted in lower ecosystem stability under the -40% treatment. The lower stability under the +40% treatment might be ascribed to unimproved dwarf shrub stability. Higher dwarf shrub and forb stability contributed to higher ecosystem stability under normal precipitation changes (±20% treatments) and CK. Species diversity was not a crucial driver of ecosystem stability. Our results indicate that precipitation alteration can regulate ecosystem stability via functional group stability (e.g. forb stability, dwarf shrub stability) and species asynchrony in a semiarid desert grassland.
降水格局的变化可能会影响植物生物多样性，从而影响生态系统的稳定性。然而，降水格局变化对生态系统稳定性的影响及其潜在机制仍不清楚。我们在半干旱荒漠草原进行了为期 3 年的野外控制实验，设置了 5 种降水处理（-40%、-20%、0%（对照）、+20%和+40%的生长季降水），以探讨降水变化对功能群稳定性、物种非同步性和多样性的影响，以及利用结构方程模型探讨生态系统稳定性的潜在机制。降水的改变对群落生物量和功能群生物量有不同的影响。此外，生态系统稳定性主要由草本植物的稳定性驱动（路径系数=0.79）。降水的变化对土壤溶解无机氮有显著影响（P<0.01），进一步通过物种非同步性影响生态系统稳定性（路径系数=0.25）。矮灌木对生态系统稳定性有稳定作用（路径系数=0.32），主要通过深根。生态系统稳定性在-40%（4.72）和+40%（2.74）降水处理中往往较低。在-40%处理下，物种非同步性和草本植物及矮灌木功能群稳定性的普遍降低导致生态系统稳定性降低。在+40%处理下，生态系统稳定性较低可能是由于矮灌木稳定性没有提高。在正常降水变化（±20%处理）和对照条件下，较高的矮灌木和草本植物稳定性有助于提高生态系统稳定性。物种多样性不是生态系统稳定性的关键驱动因素。我们的研究结果表明，降水变化可以通过功能群稳定性（如草本植物稳定性、矮灌木稳定性）和半干旱荒漠草原的物种非同步性来调节生态系统的稳定性。
