Seed processes alleviate the negative effects of grazing on plant diversity in alpine grasslands

doi:10.1093/jpe/rtag144

J Plant Ecol ›› Advance articles DOI:10.1093/jpe/rtag144

Seed processes alleviate the negative effects of grazing on plant diversity in alpine grasslands

Qin-Yuan Zhou^1,2,3, Quan-Ming Dong^1,2,3, Yu-Zhen Liu^1,2,3, Xiao-Xia Yang^1,2,3, Wen-Ting Liu^1,2,3*

1 Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining 810016, Qinghai, China
2 Key Laboratory of Alpine Grassland Ecosystem in the Three-River-Source (Qinghai University)， Ministry of Education, Xining 810016, Qinghai, China
3 Qinghai Provincial Key Laboratory of Adaptive Management on Alpine Grassland, Xining 810016, Qinghai, China

Received:2025-12-29 Accepted:2026-06-13 Published:2026-06-23
Supported by:
This study was financially supported by the Qinghai Provincial Basic Research Program (2025-ZJ-963J), the National Natural Science Foundation of China (32160340), and the Qinghai University Graduate Education and Teaching Reform Project (qdya-2604).

种子过程缓解放牧对高寒草地植物多样性的负面作用

Abstract

Abstract: The role of soil seed banks in disturbed ecosystems, especially how mixed grazing affects the entire seed fate pathway (production, dispersal, storage) and species turnover/plant diversity, is understudied as most research focuses on single grazing intensities. We conducted a controlled mixed - grazing experiment with yaks and Tibetan sheep at moderate intensity in alpine grasslands of northeastern Qinghai - Tibetan Plateau. We quantified the full seed fate pathway (production, dispersal via seed rain and canopy seed banks, storage in soil seed banks) to explore grazings impact on seed dynamics and plant diversity. Moderate grazing had an asymmetric effect: it increased community - scale seed output but reduced seed transfer to seed rain and soil seed banks. Seed rain positively influenced the soil seed bank, showing a dynamic coupling under grazing. While grazing directly decreased plant α - diversity, the soil seed bank indirectly mitigated this by mediating species turnover. Our study uncovers the complete seed fate pathway under mixed grazing. Dynamic regulation of seed bank inputs, not static storage, is key to plant community responses to chronic disturbance. The soil seed bank acts as a dynamic biodiversity regulator, and herbivore assemblage composition, not just grazing intensity, determines its ecological function.

This study examined how moderate grazing by yaks and Tibetan sheep affects seed fate pathways and plant diversity in alpine grasslands. The results show that grazing increases seed output but reduces seed transfer into seed rain and soil seed banks, while soil seed banks partly buffer diversity loss by mediating species turnover.

Key words: Soil seed bank, Species turnover, Dynamic coupling, Seed fate, Community assembly, Grazing

摘要：
土壤种子库在受扰动生态系统中的作用仍缺乏充分研究，尤其是混合放牧如何影响完整的种子命运路径(生产、扩散、储存)以及物种周转和植物多样性，目前尚不清楚，因为大多数研究主要关注单一放牧强度。我们在青藏高原东北部高寒草地开展了牦牛和藏羊中等强度混合放牧控制实验。通过量化完整的种子命运路径(生产、通过种子雨和冠层种子库扩散、在土壤种子库中储存)，探究放牧对种子动态和植物多样性的影响。中等强度放牧产生了不对称效应：它增加了群落尺度的种子输出，但减少了种子向种子雨和土壤种子库的转移。种子雨对土壤种子库具有正向影响，表明在放牧条件下二者存在动态耦合关系。尽管放牧直接降低了植物α多样性，但土壤种子库通过介导物种周转，在一定程度上间接缓解了这种负面影响。本研究揭示了混合放牧条件下完整的种子命运路径。种子库输入的动态调控，而非静态储存，是植物群落响应长期扰动的关键。土壤种子库是一个动态的生物多样性调节器，而草食动物组合组成，而不仅仅是放牧强度，决定了其生态功能。

关键词: 土壤种子库, 物种周转, 动态耦合, 种子命运, 群落构建, 放牧

Qin-Yuan Zhou, Quan-Ming Dong, Yu-Zhen Liu, Xiao-Xia Yang, Wen-Ting Liu. Seed processes alleviate the negative effects of grazing on plant diversity in alpine grasslands[J]. J Plant Ecol, DOI: 10.1093/jpe/rtag144.

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