兰州大学机构库 >生命科学学院
高山垫状植物表型变异及其对物种间相互作用与群落结构的影响
Alternative TitlePhenotypic variation of Alpine cushion plants and its effects on species interaction and community composition
蒋兴佩
Thesis Advisor肖洒
2017-05-01
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword高山垫状植物 正相互作用 胁迫梯度假说 物种性状 表型变异 囊种草
Abstract

长期以来,有关物种间相互关系的研究主要集中在负的相互作用(如竞争作用,捕食作用,寄生作用等)。近二十年来,物种间的正相互作用逐渐为广大研究者所重视,并成为当今生态学研究的热点之一。作为在高山生态系统最为常见且具有代表性的植物类群,垫状植物的正相互作用在全球范围的高山系统中广泛而大量存在,是正相互作用研究的经典范例。然而,关于垫状植物表型变异对其正相互作用影响的研究却相对较少。

本研究以典型高山垫状植物囊种草Thylacospermum caespitosum为研究对象,在中国西部高山地区选取了四个地点,研究不同环境因子胁迫条件下囊种草的表型变异及其对物种间相互作用,群落物种组成及其与环境因子的关联。研究结果表明:1、囊种草按照其表型变异可划分为疏松型和紧密型两种类型,紧密型囊种草相比疏松型囊种草而言,具有高株高,高高冠比以及高分枝密度等特点;随着环境胁迫的增加,囊种草面积趋于变小,高度趋于变矮,分枝密度趋于增加。2、疏松型囊种草比紧密型囊种草具有更强的正相互作用,两种表型囊种草对群落物种丰富度的正相互作用均随着低温胁迫梯度呈现先上升而后下降的单峰模式,而随着干旱胁迫梯度的不断增加,均呈现单调递增模式;但两种表型囊种草对群落物种多度的正相互作用则存在较大差异,对多度种间作用而言,疏松型随低温胁迫梯度呈现出单峰模式而紧密型则呈现出单调递增模式。两者对干旱胁迫的反应则截然相反,疏松型呈现出单调递增模式,而紧密型则呈现单峰模式。3、囊种草的正相互作用及生境作用对群落的物种组成在四个位点均存在显著影响,然而,囊种草的表型变异对群落物种构成的影响仅在马牙雪山和祁连山低海拔两个位点呈现显著性。4、囊种草的表型变异对微环境的影响在四个位点均不显著,这表明表型变异引起的囊种草正相互作用的差异与其对微环境的改善作用之间不存在明显相关性,其他因素,如地下生物群落等,可能是导致不同表型囊种草正相互作用产生差异的主要原因。

本研究以囊种草为例,探究了高山垫状植物表型变异及其对物种间相互作用与群落结构的影响。通过比较不同表型囊种草正相互作用差异及其对两种不同胁迫梯度的响应和群落结构的影响,阐明了表型变异对物种间相互作用的影响模式及其与环境胁迫之间的关系,进一步揭示了垫状植物的正相互作用对维系高山生态系统物种多样性与功能的重要作用,从而为全球气候变化条件下的高山生态系统保护和修复提供了理论支持与科学指引。

Other Abstract

Experiments of relationship between species mainly focused on negative interactions, such as competition, predation and parasitism while positive interaction or facilitation of species has been overlooked for a long time. Over the last two decades, since the importance has been gradually recognized by ecologists and botanists, positive interactions become one of the hotspots of ecological research.As a most widely existed and typical plant group, which facilitative interaction is common and enormous in Alpine ecosystem all over the world, cushion plant is a classic model for the investigation of positive interactions. However, few studies have been involved in the effects of cushion plant’s phenotypic variation on facilitation.We selected a typical cushion plant Thylacospermum caespitosum (Caryophyllaceae) with two contrasting phenotypes (loose and tight) as target species and conducted field survey at four Alpine sites in West China to assess phenotypic variation and its effects on species interactions, community composition and environmental variables.

Results showed: 1) According to plant traits, Thylacospermum caespitosum can be divided into two types: loose and tight cushions. Comparing with loose cushions, tight cushions had higher value in height, convexity index and stem density. Along with the increase of environmental stress, cushion areas became smaller, height became shorter whereas stem density tend to increase. 2) Loose cushions showed stronger facilitative interactions than tight ones. Meanwhile, for the interactions in richness, two phenotypes presented consistent response to different stress factors: unimodal model to thermal stress and linear model to water. However, for the interactions in abundance, loose cushions exhibited unimodal relationship whereas tight cushions exhibited monotonic relationship with temperature. The scenario was totally opposite for the aridity, where loose cushions exhibited monotonic relationship and tight cushion exhibited unimodal relationship. 3) Significant phenotypic effects and habitat effects on understory community composition were only detected in Maya and Qilian low sites. Nevertheless, an overall cushion effects existed at four sampling sites. 4) Besides, environmental variables showed no significant phenotypic effects on microhabitats. Namely, phenotypic effects on species interactions cannot be explained by the amelioration of environmental variables and there may be some potential processes, such as underground microbes, which been involved and triggered species interactions.

In conclusion, the thesis, taking Thylacospermum caespitosum as our target plant, investigated the phenotypic effects of Alpine cushion plants on interspecific interactions and their response to environmental stresses. The results further revealed the important effect of the cushion plants on function and species diversity of Alpine ecosystems, thus providing theoretical support and scientific guidance for the protection and restoration of Alpine ecosystems under global climate change.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/221384
Collection生命科学学院
Recommended Citation
GB/T 7714
蒋兴佩. 高山垫状植物表型变异及其对物种间相互作用与群落结构的影响[D]. 兰州. 兰州大学,2017.
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