Data from: Warming reduces the compositional and biomass stability of alpine meadows via declines in species richness and functional dispersion

Understanding the mechanisms that maintain grassland community composition
and biomass stability is crucial for the functions and
services provided by ecosystems under climate change, and the
development of grassland management and restoration
strategies. However, how the potential mechanisms of warming and
altered precipitation combine to affect community compositional and
biomass production stability is still not clear, especially in alpine
ecosystem. Here, we conducted a 4-year
field experiment to manipulate
warming and precipitation alteration in an alpine
meadow on the eastern Tibetan
Plateau to investigate
how climate change affects the
temporal stability of plant community composition
and biomass. We showed that warming alone decreased
community biomass stability, and it combined
with precipitation alteration decreased compositional stability,
respectively, while precipitation alteration alone had no significant
effect. The effect of warming on community
compositional and biomass stability was influenced by
precipitation change. Warming reduced community
compositional and biomass stability by decreasing functional
dispersion, while precipitation addition and reduction will
alleviate and exacerbate the negative effects of warming on community
composition and biomass stability by influencing species
richness. Moreover, biomass stability is largely determined by
asynchrony among species. Our results suggest that climate
warming and combined with precipitation alteration would reduce
alpine community compositional stability primarily by reducing
functional dispersion and species richness, and reduce the
stability of community biomass via decreasing
compositional stability. Thus, our findings provide valuable information
for the sustainable functioning of
grassland maintenance, highlighting that future
grassland conservation and management should consider
increasing species and functional diversity to mitigate
or recover the negative impacts of climate warming on alpine
plant community composition and biomass stability.

明晰维持草地群落组成与生物量稳定性的机制，对于气候变化背景下生态系统所提供的服务与功能，以及草地管理与修复策略的制定均至关重要。然而，增温与降水改变的潜在机制如何共同作用于群落组成与生物量生产稳定性，目前仍不明晰，在高山生态系统中这一问题尤为突出。本研究于青藏高原东部的高山草甸开展为期4年的野外操控实验，通过调控增温与降水处理，探究气候变化如何影响植物群落组成与生物量的时间稳定性。研究结果显示，单独增温会降低群落生物量稳定性，增温结合降水改变则会降低群落组成稳定性，而单独的降水改变未产生显著影响。增温对群落组成与生物量稳定性的影响受降水变化调控。增温通过降低功能离散度（Functional Dispersion）削弱了群落组成与生物量稳定性；而降水增加与降水减少则分别通过影响物种丰富度（Species Richness），缓解与加剧增温对群落组成与生物量稳定性的负面影响。此外，生物量稳定性在很大程度上由物种间的异步性（Species Asynchrony）所决定。本研究结果表明，气候增温及其与降水改变的组合处理，主要通过降低功能离散度与物种丰富度，削弱高山群落组成稳定性；并通过降低群落组成稳定性，进一步降低群落生物量稳定性。综上，本研究结果可为草地可持续功能的维持提供重要参考，同时指出未来草地保护与管理工作应考虑提升物种与功能多样性，以缓解或修复气候增温对高山植物群落组成与生物量稳定性造成的负面影响。