<b>DATA FOR--</b><b>Negative feedback</b><b> as self-sustaining</b> <b>mechanism of grazing ecosystems: A notable but transient biotic refuge effect on community reproductive traits</b>

1. Unpalatable plants can provide biotic refuges for their neighbors, thus playing important roles in community diversity protection, especially in community restoration. However, the synergistic response of unpalatable species populations and their biotic refuge effects to grazing intensity and duration remains poorly understood.2. Here, we observed a four grazing intensity experiments for three consecutive years to examined the dynamic responses of <i>Morina kokonorica </i>population, a thorny, unpalatable species, and its biotic refuge effects to grazing intensity and duration.3. We revealed that low to moderate grazing pressures increased the frequency of adult <i>M. kokonorica</i> plants, while under high grazing pressures, the population experienced decline. <i>M. kokonorica</i> provided biotic refuges for the community structure and reproductive traits, primarily by alleviating the negative impacts of grazing on the reproductive branches of dominant Poaceae species. Communities with <i>M. kokonorica</i> exhibited 1.4 times, 5.6 times, and 4.9 times higher numbers of harvested species, reproductive branches, and seeds, respectively, compared to those without<i> M. kokonorica </i>in 2020. Notably, these refuge effects were more pronounced under heavy grazing. However, as grazing duration extended, the defense area and population of <i>M. kokonorica</i> diminished, ultimately leading to a collapse of the protective effect.4. <i>Synthesis and applications</i>. Our results underscored the importance of grazing duration alongside intensity in shaping biotic refuges effect, which will promote a reconsideration of the ecological role of unpalatable species in grazing management, especially in grassland restoration. Unpalatable plants serve as indicators of unhealthy grazing and acted as a self-sustaining mechanism for grassland ecosystems. Management based on the eradication of unpalatable herbs may not only fail to restore degraded grasslands, but may also exacerbate degradation due to the removal of refuges.1. 适口性差的植物可为其邻近物种提供生物庇护（biotic refuge），进而在群落多样性保护，尤其是群落修复中发挥重要作用。然而，适口性差物种种群及其生物庇护效应对放牧强度与放牧时长的协同响应机制仍有待阐明。 2. 本研究通过开展为期三年、涵盖四个放牧梯度的野外试验，探究了带刺适口性差物种青海刺参（Morina kokonorica）种群及其生物庇护效应对放牧强度与放牧时长的动态响应。 3. 研究结果表明：低至中度放牧压力可提升成年青海刺参的种群频率，而高强度放牧压力下其种群则呈现衰退趋势。青海刺参可通过缓解放牧对禾本科（Poaceae）优势物种生殖枝的负面影响，为群落结构与繁殖性状提供生物庇护。2020年，相较于无青海刺参分布的群落，含青海刺参的群落其可收获物种数、生殖枝数与种子数分别高出1.4倍、5.6倍与4.9倍。值得注意的是，此类庇护效应在重度放牧条件下更为显著。但随着放牧时长的增加，青海刺参的庇护范围与种群规模逐渐缩减，最终导致其保护效应崩塌。 4. 综合与应用（Synthesis and Applications）：本研究结果强调了放牧时长与放牧强度在调控生物庇护效应中的同等重要性，这将推动学界重新审视适口性差物种在放牧管理，尤其是草原修复中的生态功能。适口性差的植物可作为放牧状态失衡的指示物种，同时也是草原生态系统的自我维持机制之一。若基于根除适口性差草本植物的管理策略，不仅无法实现退化草原的修复目标，还可能因移除庇护位点而加剧草原退化。