Grazing disturbance increases transient but decreases persistent soil seed bank
Grazing disturbance increases transient but decreases persistent soil seed bank
复制标题
放牧干扰增加了瞬时性但减少了持久性土壤种子库
DOI：
10.1002/eap.1706
复制
发表时间：
2018
影响因子：
5
通讯作者：
Guozhen Du
中科院分区：
文献类型：
--
作者：
Miaojun Ma;Jeffrey L. Walck;Zhen Ma;Lipei Wang;Guozhen Du
很少有研究探讨放牧干扰对土壤种子库的影响是直接发生的，还是通过地上植被和土壤性质间接发生的。种子库在高山湿地恢复中的潜在作用也是未知的。利用结构方程模型（SEM）探讨了放牧干扰对种子库的直接影响以及通过地上植被和土壤性质对种子库的间接影响。我们还研究了种子库在不同放牧强度下对湿地恢复潜力的作用：低（围栏，仅冬季放牧），中等（季节性放牧）和高（全年放牧）。在春季和夏季，各深度（0-5，5-10，10-15 cm）和整个深度（0-15 cm）的种子库物种丰富度和密度在不同放牧强度下均无显著差异。春季和夏季放牧干扰对种子库的丰富度和密度没有直接影响，也没有通过直接影响植被丰富度和丰富度而间接影响种子库。放牧干扰通过对土壤水分和全氮的直接影响（负相关）和对植被丰富度的间接影响，间接增加了春季种子库密度，降低了夏季种子库密度。植被的物种组成随放牧制度的变化而变化，但种子库的物种组成没有变化。随着放牧干扰的增加，种子库与地上植被的相似性在浅层和全层都有增加的趋势，但仅在春季有增加的趋势。虽然种子库的大小与放牧强度几乎没有变化，但放牧干扰增加了瞬时种子的数量，但减少了持久性种子。在土壤中储存的持久性种子在植被再生和退化湿地生态系统的恢复中可发挥关键作用。种子库应该是高山湿地恢复计划的一个组成部分。
Very few studies have examined whether the impacts of grazing disturbance on soil seed banks occur directly or indirectly through aboveground vegetation and soil properties. The potential role of the seed bank in alpine wetland restoration is also unknown. We used SEM (structural equation modeling) to explore the direct effect of grazing disturbance on the seed bank and the indirect effect through aboveground vegetation and soil properties. We also studied the role of the seed bank on the restoration potential in wetlands with various grazing intensities: low (fenced, winter grazed only), medium (seasonally grazed), and high (whole‐year grazed). For the seed bank, species richness and density per plot showed no difference among grazing intensities for each depth (0–5, 5–10, 10–15 cm) and for the whole depth (0–15 cm) in spring and summer. There was no direct effect of grazing disturbance on seed bank richness and density both in spring and summer, and also no indirect effect on the seed bank through its direct effect on vegetation richness and abundance. Grazing disturbance indirectly increased spring seed bank density but decreased summer seed bank density through its direct effect (negative correlation) on soil moisture and total nitrogen and its indirect effect on vegetation abundance. Species composition of the vegetation changed with grazing regime, but that of the seed bank did not. An increased trend of similarity between the seed bank and aboveground vegetation with increased grazing disturbance was found in the shallow depth and in the whole depth only in spring. Although there was almost no change in seed bank size with grazing intensities, grazing disturbance increased the quantity of transient seeds but decreased persistent seeds. Persistent seeds stored in the soil could play a crucial role in vegetation regeneration and in restoration of degraded wetland ecosystems. The seed bank should be an integral part of alpine wetland restoration programs.