Seed banks trigger ecological resilience in subalpine meadows abandoned after arable farming on the Tibetan Plateau
Seed banks trigger ecological resilience in subalpine meadows abandoned after arable farming on the Tibetan Plateau
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种子库激发了青藏高原耕种后废弃的亚高山草甸的生态恢复力
DOI：
10.1002/eap.1959
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发表时间：
2019
影响因子：
5
通讯作者：
Guozhen Du
中科院分区：
文献类型：
--
作者：
Miaojun Ma;Carol C. Baskin;Wenjin Li;Yunpeng Zhao;Yin Zhao;Liang Zhao;Ning Chen;Guozhen Du
虽然长期的农业活动经常会减少生物多样性，但目前尚不清楚这种生物多样性的丧失是否容易逆转。种子库的重要生态功能是生态记忆，这一点毋庸置疑，但目前还没有研究者探讨种子库在草地生态系统恢复力和阈值理论中的作用。我们使用了空间换时间的代位求偿法天然草地（从未耕种，但用于适度凝视）和草地耕种30年，然后放弃了1，10和20年，以确定是否可以逆转到自然植被状态的亚高山草甸的生物多样性/生态系统，并调查土壤种子银行在草地生态系统恢复和弹性的作用。经过20年的天然更新，地上植被组成和性质已恢复到天然草甸状态，这表明没有越过临界阈值。种子库的组成和结构几乎没有变化，农业干扰几十年。持久性种子库对1年撂荒地植被更新的贡献最大，其种子密度最高。种子库与地上植被的相似性和种子密度随弃耕年限的增加而降低。由于种子库仍然反映了所需的状态，系统具有固有的弹性，并且没有超过过渡阈值。因此，高多样性的持久种子库是该生态系统高弹性的重要指标。早期废弃田地中的种子库和植被之间的高度相似性可能表明生态恢复力已经被触发，并且是需要干预以避免状态转变的警告信号。在应用交替稳定态理论进行生态恢复时，应重视土壤种子库的研究。
Although long‐term agricultural activity frequently decreases biodiversity, it remains unclear whether such biodiversity losses are readily reversible. There is no doubt that the important ecological function of seed bank is ecological memory, but few researchers have explored the role of seed banks in grassland ecosystem resilience and threshold theory. We used a space‐for‐time subrogation method, i.e., a natural meadow (never farmed but used for moderate gazing) and meadows farmed for 30 yr and then abandoned for 1, 10, and 20 yr, to determine if the biodiversity/ecosystem of subalpine meadows could be reversed to the natural vegetation state and to investigate the role of soil seed banks in grassland ecosystem restoration and resilience. After 20 yr of natural regeneration, aboveground vegetation composition and properties had recovered to the natural meadow state, suggesting that critical thresholds were not crossed. Seed bank composition and structure exhibited almost no change after agricultural disturbance for decades. The persistent seed bank had the highest contribution to vegetation regeneration in the 1‐yr abandoned field, which had the highest seed density. Similarity between the seed bank and aboveground vegetation and seed density decreased with years since abandonment. Since the seed bank still reflected the desired state, the system had inherent resilience and had not have crossed the transition threshold. Thus, high‐diversity persistent seed banks are an important indicator of high resilience of this ecosystem. High similarity between the seed bank and vegetation in early‐abandoned fields may indicate that ecological resilience is triggered and be a warning signal that interventions are needed to avoid a state transition. In applying alternative stable state theory to ecological restoration, much attention should be given to the soil seed bank.