Dominant species rather than plant biodiversity shape grassland resistance and recovery in response to heatwaves and mowing

• Published in: The Journal of ecology
• Main Authors: Wang, Zhaozhao, Dong, Xiaobing, De Boeck, Hans J., Dong, Gang, Jiang, Shicheng, Chen, Jingyan, Hu, Yalin, Shao, Changliang, Qu, Lu‐Ping
• Format: Journal Article
• Language: English
• Published: 12.08.2025
• ISSN: 0022-0477; 1365-2745
• DOI: 10.1111/1365-2745.70138

Ongoing climate change has increased the frequency and intensity of climate extremes such as heatwaves, impacting terrestrial ecosystems. Grasslands are often shaped by human activities such as mowing, which may modulate their responses to climate extremes. However, the mechanisms underlying such responses and the factors important in stabilizing grassland functioning under environmental disturbance are currently poorly understood. In this study, we experimentally compared the effects of heatwaves and mowing on the functioning (based on CO 2 exchange) of two different grassland types, Stipa krylovii typical grassland ( Sti ‐Tpl) and Leymus chinensis meadow steppe ( Ley ‐Mdw), in Inner Mongolia. In each grassland, ecosystem CO 2 fluxes and plant community characteristics (biomass, community structure and biodiversity indices) were recorded. We specifically focused on the stability of grassland CO 2 exchange during heatwave events (resistance), the capacity to regain functionality afterwards (recovery) and the plant factors influencing these resilience metrics in both grasslands. The results indicate non‐linear temporal trajectories in carbon flux recovery, with a weak correlation between resistance and recovery. Ecosystem respiration (RE) generally exhibited greater resistance and recovery to heatwaves than gross ecosystem production (GEP); GEP reduction led to a decrease in net ecosystem production (NEP). However, local mowing practices partially mitigated these negative effects. The importance value (Iv) of dominant species and biodiversity both positively influenced NEP resistance, but their effects on NEP recovery were opposite, as Iv enhanced recovery while biodiversity reduced it. Finally, the contribution level of dominant species to grassland stability was closely related to their Iv in the plant community. Synthesis . In this study, we investigated the complex factors influencing ecosystem resistance and recovery to heatwaves and mowing in two distinct grasslands. We found that the physiology, morphology and regeneration traits of the dominant species in each grassland community explained most of the divergence of grassland function stability. Thus, to buffer ecosystems against adverse impacts of climate extremes in conjunction with land management, it can be advantageous to focus on the maintenance or selection of dominant species rather than solely on increasing species richness. 气候变化导致极端气候事件(如热浪)的频率和强度增加，并对草地生态系统的碳循环产生显著影响。同时，草地生态系统常常受到人类活动(例如刈割)的干扰，这种活动可能改变草地生态系统对极端气候事件的响应机制。本研究的重点在于揭示草地生态系统对热浪的响应机制及其生态功能的稳定性。 本研究通过人工模拟的方法，明确热浪事件下刈割对内蒙古两种不同草地类型( Stipa krylovii )典型草地( Sti ‐Tpl)和 Leymus chinensis 草甸草原( Ley ‐Mdw)碳通量的影响。评估其碳通量并阐明植物群落特征(包括生物量、群落结构和生物多样性指标)对热浪和刈割的响应，特别关注两种草地在热浪期间的二氧化碳交换稳定性(抗性，resistance)及热浪后的恢复能力(恢复力，recovery)，阐明影响两种草地稳定性指标的关键植物因素。 研究结果表明草地碳通量的恢复呈现非线性时间轨迹，抗性和恢复力之间相关性较弱。生态系统的呼吸(RE)相较于总生态系统生产力(GEP)在热浪中表现出更强的抗性和恢复力，而GEP的变化是导致净生态系统生产力(NEP)下降的主导因素。刈割措施能够减轻热浪对草地碳通量的负面影响。优势植物种的重要值(Iv)和生物多样性对NEP的抗性有正面影响，但对恢复力的影响则相反，高重要值增强恢复力而高生物多样性则削弱恢复力。优势植物种对草地稳定性的贡献程度与其在群落中的重要性密切相关 本研究探讨了影响不同草地生态系统对热浪和刈割的抗性和恢复力的关键因素。研究发现，不同草地群落中优势物种的生理、形态和再生特性是解释草地生态系统功能稳定性差异的关键因素。本研究强调在草地生态系统的管理中应综合考虑优势物种在群落中的作用，而不仅仅关注物种丰富度，由此来减缓未来极端气候事件对草地生态系统碳通量的不利影响。