长期施肥对黄土高原典型草原群落稳定性的影响及机制研究
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引用本文:刘 晶,杨 雪,张 博,晏昕辉,温仲明,李 伟.长期施肥对黄土高原典型草原群落稳定性的影响及机制研究[J].西北植物学报,2021,41(2):310~316
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作者单位
刘 晶1,2,杨 雪1,2,张 博3,晏昕辉1,温仲明1,2,3,李 伟2,3* (1 西北农林科技大学 草业与草原学院陕西杨陵 7121002 西北农林科技大学 水土保持研究所 陕西杨陵 7121003 中国科学院水利部水土保持研究所陕西杨陵 712100) 
基金项目:国家自然科学基金(41601586,41671289);
中文摘要:施肥是当前草地生态系统最常见的人为干扰方式之一,可导致草地生物多样性和生态系统稳定性发生显著变化。该研究以黄土高原典型草原为研究对象,通过连续8年的氮肥(尿素)野外添加试验,分析不同氮肥处理(分别为0、5、10、20、40和80 g·m-2)对草地群落稳定性的影响,并分析检验可能影响群落稳定性的四个潜在机制(物种多样性、物种同步性、投资组合效应和优势度),以明确施肥对群落稳定性的影响及其潜在机制,为黄土高原恢复草地的合理利用提供理论依据。结果表明:(1)随着施肥水平的增加,群落稳定性(S)降低,并在施肥处理为 20 g·m-2时开始极显著下降(P<0.01)。(2)施肥极显著降低了物种的丰富度(R)和优势度指数(D)(P<0.01),但物种同步性(B)和均值 方差的比例指数(z)并没有发生显著变化(P>0.05)。(3)物种丰富度(R)与群落稳定性(S)之间呈正相关关系,而优势度指数(D)与群落稳定性(S)不相关。研究认为,在人为施肥干扰下,黄土高原典型草原的物种丰富度下降导致群落稳定性下降,表明物种多样性对维持草地群落稳定具有重要作用。
中文关键词:草地生态系统  施肥  稳定性  物种多样性
 
Effect of Long term Fertilization on Community Stability of Typical Steppe and the Underlying Mechanisms on the Loess Plateau
Abstract:Fertilization is one of the most common ways of human disturbance in the current grassland ecosystems, which can lead to changes in grassland biodiversity and ecosystem stability. At present, a few studies, however, have explored the effect of fertilization on community stability and the underlying mechanisms, but there are many controversies. For this reason, we took the typical steppe of the Loess Plateau as the research object, and through 8 consecutive years of field experiment of adding nitrogen fertilizer (urea), we studied different nitrogen fertilizer treatments (respectively 0, 5, 10, 20, 40, 80 g·m-2) influence on the stability of the grassland ecosystem, and tested four underlying mechanisms (species diversity, species synchrony, portfolio effect, dominance) that may affect the stability of community, to clarify the impact of fertilization on community stability and its underlying mechanism thus providing a theoretical basis for the rational use of grassland restoration on the Loess Plateau. The results showed that: (1) as the fertilization level increased, the community stability (S) decreased, and it began to decrease significantly when the fertilization treatment was 20 g·m-2 (P<0.01). (2) Fertilization significantly reduced the species richness (R) and dominance index (D) (P<0.01). However, the species synchrony (B) and the mean variance ratio index (z) did not change significantly (P>0.05). (3) There was a positive correlation between species richness (R) and community stability (S), while dominance index (D) was not correlated with community stability (S). Studies suggested that under the disturbance of fertilization, the decline in species richness of typical steppe on the Loess Plateau led to a decline in community stability, indicating that species diversity plays an important role in maintaining the stability of grassland ecosystem.
keywords:grassland ecosystem  fertilization  stability  species diversity
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