Effects of disturbance intensity on seasonal dynamics of alpine meadow soil seed banks on the Tibetan Plateau
Effects of disturbance intensity on seasonal dynamics of alpine meadow soil seed banks on the Tibetan Plateau
复制标题
扰动强度对青藏高原高寒草甸土壤种子库季节动态的影响
DOI：
10.1007/s11104-012-1560-5
复制
发表时间：
2013-08-01
期刊：
影响因子：
4.9
通讯作者：
Du, Guozhen
中科院分区：
文献类型：
--
作者：
Ma, Miaojun;Zhou, Xianhui;Du, Guozhen
背景与目的土壤种子库过程的信息对了解植被动态至关重要。土壤种子库在许多生态系统中的重要性已有文献记载，但在一些敏感生境，如青藏高原高寒草甸，土壤种子库的作用尚未被充分认识。方法研究了青藏高原高寒草甸4种干扰强度下土壤种子库的季节动态以及种子大小分布与干扰强度的关系。结果随着干扰强度的增加，埋藏种子密度增大，物种丰富度和物种多样性降低。各层(0~2、2~7、7~12 cm)和整层(0~12 cm)种子密度和物种丰富度随季节变化。种子库物种组成受季节影响不大。种子大小分布没有随干扰的增加而变化的趋势。季节种子库周转率随干扰强度的增加而增加。NMDS分析结果表明，各季节种子库和植被的物种组成呈现出较一致的格局。结论虽然各季节植被和种子库的物种组成总体上表现出较低的相似度，但在受干扰最严重的生境中相似性最高。无论干扰强度大小，种子库的物种组成没有发生变化，但种子密度随干扰强度的增加而降低。高山植物群落的干扰可能会增加更新生态位的持久性。种子库的再生和营养繁殖有助于在高度干扰的生境中建立地上植被。在轻度干扰区，克隆物种在植被恢复中起着重要作用，土壤种子库对植被恢复的贡献很小。
Background and AimsInformation on soil seed bank processes is crucial for understanding vegetation dynamics. Despite the documented importance of soil seed banks in many ecosystems, their role is not fully understood in some sensitive habitats, such as the alpine meadows of the Tibetan Plateau.MethodsWe studied the seasonal dynamics of the germinable soil seed bank under four disturbance intensities in an alpine meadow on the Tibetan Plateau as well as seed size distribution relative to disturbance intensity. Composition of the seed bank was compared with that of the standing vegetation.ResultsDensity of buried seeds increased with disturbance intensity, but species richness and species diversity decreased. Seed density and species richness of the seed bank varied seasonally in all layers (0–2, 2–7, 7–12 cm) and the whole (0–12 cm). The species composition of seed bank was not significantly influenced by season. There was no trend in seed size distribution as disturbance increased. Seasonal seed bank turnover rates increased with increase in disturbance. The result of the NMDS showed that species composition of seed bank and vegetation exhibited a fairly uniform pattern in each season.ConclusionsAlthough as a whole the species composition of the vegetation and seed bank showed a relatively low degree of similarity in each season, similarity was highest in the most disturbed habitat. There was no alteration in species composition of seed bank regardless of disturbance intensity, but seed density decreased as disturbance increased. Disturbances in alpine plant communities might increase persistence of regeneration niches. Regeneration from the seed bank together with vegetative reproduction contributed to aboveground vegetation in highly disturbed habitats. Clonal species played an important role in regeneration of vegetation in slightly disturbed areas, where there was little contribution of ruderals from soil seed banks.