有机肥对草甸草原植物群落及物种多样性的影响

EFFECT OF ORGANIC FERTILIZER ON PLANT COMMUNITIES AND SPECIES DIVERSITY IN MEADOW STEPPE

关键词:  有机肥  草甸草原  群落特征  植物功能群  物种多样性

Key words:  organic fertilizer  meadow steppe  community characteristics  plant functional groups  species diversity

摘要:

目的 施肥措施是一项维持草原生态系统养分平衡的有效管理方式。文章通过田间试验研究了不同有机肥施用量对草地植物群落的影响，为退化草地的恢复和改良提供参考和理论依据。方法 2014—2021年立足于呼伦贝尔羊草（Leymus chinensis ）草甸草原连续多年的施肥控制试验样地，设置了4个长期施肥处理：不施肥处理（Y0）、低水平有机肥处理（Y1）、中水平有机肥处理（Y2）和高水平有机肥处理（Y3），研究植物物种重要值、功能群和群落物种多样性，并分析在不同施肥处理下的相关性关系和交互作用。结果 （1）随着施肥水平的升高羊草重要值呈抛物线函数变化趋势，且中度施有机肥处理下最高；有机肥添加后的群落以及优势种羊草植物特征数值显著高于不施肥处理；植物群落多样性指数均随着施肥水平的升高逐渐减小。（2）施有机肥处理的群落高度、密度、盖度以及地上生物量的响应比显著高于不施肥处理；植物群落物种多样性指数响应比随着施肥水平的升高而降低的趋势比较明显。（3）群落功能群分类与不同施肥水平之间的交互作用显著，禾本科、豆科和毛茛科植物的重要值在不施肥处理与施肥处理之间差异显著；禾本科的重要值与多样性指数之间呈极显著负相关，豆科、龙胆科、毛茛科、伞形科和莎草科的重要值与多样性指数之间呈极显著正相关，百合科和鸢尾科的重要值与Pielou均匀度指数呈显著正相关。结论 群落中主要的禾本科、豆科和毛茛科等功能群与施肥水平之间产生了显著的交互性以及相关性，施有机肥降低了羊草草甸草原植物群落物种多样性指数及其响应比，提高了禾本科植物优势种羊草的重要值以及草地生产力。

Abstract:

Fertilization is an effective management practice to maintain the nutrient balance of grassland ecosystems. A field study was used to study the effects of different organic fertilizer application rates on plant communities, aiming to provide reference and to reveal mechanisms for the restoration and improvement of degraded grasslands. And the study was conducted on the Leymus chinensis meadow steppe for fertilization control experiment in Hulunbuir, Inner Mongolian from 2014 to 2021. There were four fertilizer application rates for the experiment: no fertilizer application, the low level of application, the medium level of application and the high level of application correlations and interactions among plant species importance values, functional groups and community species diversity under different fertilizer application rates were analyzed. The results were listed as follows. The important value of Leymus chinensis showed a trend of the parabolic function with fertilizer application rates, reaching its highest value at the medium level; the plant characteristic values of community and Leymus chinensis after organic fertilizer addition were significantly higher than those of the non-fertilized treatment; the plant community species diversity index decreased with fertilizer application rates. The response ratios of community height, density, coverage and above-ground biomass with fertilizer amendment were significantly higher than those without fertilizer application; the tendency for the plant community species diversity index response ratio to decrease with increasing levels of fertilizer application was relatively significant. The interactions between community functional groups and fertilizer rates were significant, and the important values of Gramineae, Leguminosae and Ranunculaceae were significantly different between without and with fertilizer applications; there was a highly significant negative correlation between the important values of Gramineae and the diversity index, a highly significant positive correlation between the important values of Leguminosae, Gentianaceae, Ranunculaceae, Umbelliferae, and Cyperaceae and the diversity index, and a significantly positive correlation between the important values of Liliaceae and Iridaceae and the Pielou evenness index. In summary, there is a significant interaction and correlation between the major functional groups of Gramineae, Leguminosae and Ranunculaceae in the community and fertilizer amendment. Organic fertilizer applications resulted in reducing the species diversity index and its response ratio of the Leymus chinensis meadow steppe plant community, and increasing the important values of Gramineae and Leymus chinensis and grassland productivity.