兰州大学机构库 >生命科学学院
禾草优势种丧失对亚高寒草甸植物生理生态特征和群落结构的影响
Alternative TitleEffect of dominant grass loss on plant eco-physiological characteristics and community structure in Subalpine Meadows on the Tibetan Plateau
张如兰
Thesis Advisor李金花 ; 李文金
2018-05-25
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword去除实验 禾草优势种 生理生态特征 植物功能群 相互作用
Abstract

全球气候变化和人类活动的影响,导致了生物多样性严重丧失。在不同的生态类型和生态过程中,物种丧失对生态系统的影响也不相同。本文通过一个7年连续去除实验,即去除青藏高原亚高寒草甸的禾草优势种垂穗鹅观草(Roegneria kamoji)、垂穗披碱草(Elymus dahuricus)和赖草(Leymus secalinus)的组合研究优势种丧失对常见物种甘青蒿(Artemisia tangutica)、老鹳草(Geranium wilfordii)、莓叶委陵菜(Potentilla fragarioides)、圆叶堇菜(Viola striatella)和紫花苜蓿(Medicago sativa)的生理生态特征,以及植物多样性和生产力的影响。

主要结果如下:1.禾草优势种组合连续去除三个生长季后对常见种的净光合速率没有显著的影响;显著降低了莓叶委陵菜的气孔导度,甘青蒿和圆叶堇菜的水分利用效率和老鹳草的胞间二氧化碳浓度;显著增加了甘青蒿的蒸腾速率和地上生物量。总体而言,保留的常见种对优势种禾本科物种组合的丧失的响应是不显著的,且具有物种特异性。2.去除禾草优势种组合对群落总丰富度、香农-维纳指数以及均匀度没有显著的影响,但增加了杂类草的丰富度。在不同的去除年份增加程度有所差异,说明禾草优势种和亚优势种杂类草之间存在竞争作用。去除前两年,这种竞争作用最显著,之后随着去除时间的增加,这种作用逐渐减弱;3.去除禾草优势种组合显著降低了群落总生物量和总盖度,这说明保留的其他植物功能群没有对丧失的生物量和盖度进行完全补偿,支持了质量比假说。

Other Abstract

Due to global climate change and human activities, a large number of species have been lost. Loss of species has different effects on ecosystems in different ecological types and ecological processes. In this paper, we removed the combination of Elymus dahuricus, Roegneria kamoji and Leymus secalinus which are dominant grasses in a subalpine meadow on the Qinghai-Tibet Plateau over 7 years, in order to study the effect of dominant species loss on the eco-physiological characteristics of common species include Artemisia tangutica, Geranium wilfordii, Potentilla fragarioides, Viola striatella and Medicago sativa, as well as on the diversity and productivity of community and functional groups.

 The result showed that:1. The removal of dominant species combination had no significant effect on the net photosynthetic rate (PN) of common species. However,removing dominant species reduced the stomatal conductance (Gs) of Potentilla fragarioides,the water use efficiency (WUE) of Viola striatella and the intercellular CO2 concentration (Ci) of Geranium wilfordii significantly. On the other hand, removing dominant species significantly increased the transpiration rate (E) and the aboveground biomass of Artemisia tangutica. Overall, the responses of the common species to the removal of dominant grass were not significant and these responses were species-specific.2. Removing the combination of dominant grasses did not have a significant effect on the community richness, but increased the forb richness and the magnitude of increase was different in different years. There was no significant effect on the Shannon-Winner index and evenness. However, there were significant differences in the Shannon-Wiener index and evenness in different treatment years. These indicate that there is a competitive effect between dominant species and subdominant species. After two years of removal, this competitive effect was significant, but this competition effect weakens or even disappears with the increase of removal year.3. Removal of dominant grass significantly decreased total community biomass and total coverage, suggested that the remaining plant functional groups did not fully compensate for the lost biomass, supporting the mass ratio theory.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/221258
Collection生命科学学院
Recommended Citation
GB/T 7714
张如兰. 禾草优势种丧失对亚高寒草甸植物生理生态特征和群落结构的影响[D]. 兰州. 兰州大学,2018.
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