XTBG OpenIR  > 西双版纳热带植物园毕业生学位论文
哀牢山湿性常绿阔叶林附生蕨类植物的功能性状及其对环境变化的响应
Alternative TitleFunctional traits of epiphytic ferns and their responses to environmental changes in subtropical moist forest of Ailao Mountains
陈泉
Subtype博士
Thesis Advisor刘文耀
2019
Degree Grantor中国科学院大学
Place of Conferral中国科学院西双版纳热带植物园
Degree Name博士
Degree Discipline生态学
Keyword附生蕨类植物,功能性状,森林退化,环境变化,湿性常绿阔叶林
Abstract

功能性状影响着植物个体的定植、存活、生长与死亡,它们能够反映植物资源获取的能力以及在应对环境变化时所采取的生态策略。在群落和物种水平上,植物功能性状研究已成为解决一些关键生态学问题的有效途径。附生植物是森林生态系统中重要的组成部分之一,而附生蕨类植物是附生维管植物中的第二大类群,它们对自然或人为活动导致的环境变化非常敏感。然而,目前对附生蕨类植物的功能性状研究仍然滞后,人们在附生蕨类植物如何应对环境条件变化及人为干扰方面仍了解甚少。本研究以哀牢山木果柯原生林及其退化后形成的老龄栎类次生林和旱冬瓜林中的附生蕨类植物为对象,分别对其中常见或优势物种在不同生长时期及生境条件下的形态、生理和养分特征等进行测定,并从群落或物种的层次上,探讨了森林退化对附生蕨类植物功能性状的影响,以及附生蕨类植物对环境变化的响应和生态策略,以期为深入研究山地森林生态系统组成、结构及功能动态提供科学依据。研果表明:(1)森林退化对附生蕨类植物的物种多样性和功能多样性均发生了显著影响。在哀牢山徐家坝地区原生林中共调查到31 种附生蕨类和石松类植物,而老栎类次生林和旱冬瓜林中分别只有20 种和16 种。Shannon-Wiener 多样性指数Simpson 指数、均匀度指数等物种多样性指数随森林退化而显著降低,物种多样指数和功能多样性指数之间存在显著的正相关关系。(2)附生蕨类植物不同生长段的个体在水分维持及碳同化能力上有较大差异,大部分功能性状与个体生物量之在异速生长关系。生长早期的个体对水分的变化较为敏感,其自然失水速率较快但水后能快速地从干旱胁迫中恢复,而碳同化速率相对较低;随着个体的发育,附生植物在生长后期具有更强的耐旱性,光合能力较高,但经历干旱后,其恢复速度相较慢。附生蕨类植物生理生态学性状在种内及种间的差异体现了耐脱水性状及经济之间的相互关联和权衡关系。(3)在林冠垂直高度梯度上,原生林中占优势的棕鳞瓦韦(Lepisorus scolopendium)、二色瓦韦(L. bicolor)和高山条蕨(Oleandra wallichii)大部分的功能性状表现出较大的种内差异。林冠下层阴湿树干上附生的个体具有较大的叶长、叶宽、比叶面积及相对较高的叶绿素含量和最大光合速率;而在光照条件较强的林冠上层,附生蕨类植物具有小而厚的叶片,且叶片的肉质性较高,保水能力较强,光合能力变弱。(4)在森林退化过程中,棕鳞瓦韦和二色瓦韦由专性附生转变为兼性附生,它们在原生林中仅分布于林冠内,并以8~16m冠层中的相对多度最高;在次生林中二者的附生个体主要分布于0~4m 的范围,且们在附生和地生生境中的相对多度随林冠开阔度的增加而升高。二者的叶片功能性也随森林的退化而发生改变,功能性状之间的权衡关系使二者在原生林和次生林附和地生生境中采取不同的资源利用策略:原生林中的附生个体具有更强的光捕获力而次生林中的附生个体表现出更强的光合能力和资源利用效率;在同类次生林中,生个体趋向于适应弱光环境,且比附生个体具有更高的养分利用效率。(5)棕鳞韦和二色瓦韦的根系包含4 级根序。森林退化后,根系分枝数量增多,尤其是地生体的一级根和二级根所占的比例比附生个体大,根系的吸收功能增强;此外,附生蕨类植物根系的形态和生长性状随林冠开阔度的增加和生长基质的变化发生了一系列的改变,并表现出不同的根系觅食策略;相对于形态性状,根系的生长性状对根系呈现出不同的觅食策略关系更为密切。综合以上结果,在群落水平上,森林的退化导致附生蕨类植物的物种多样性及功能多样性显著下降,这在一定程度上影响了其群落的稳定性和功能的发挥。在物种水平上,附生蕨类植物的功能性状具有较强的可塑性且存在权衡关系,使其能在不同生长发育阶段及环境条件发生变化时,形成不同的生态策略以充分利用环境中有限的资源,从而维持个体的存活和生长。

Other Abstract

Functional traits represent attributes that influence the establishment, survival, growth and death of the plant individuals, reflecting the resource capture capacity and the ecological strategies of plants during the shift in environmental conditions. From species to community levels, trait-based research have been an effective approach to solve some key ecological problems. Epiphytes are one of the most important components in forest ecosystem. Among them, epiphytic ferns represent the second largest taxon in epiphytic vascular plants, which are sensitive to environmental variation resulting from natural or anthropological factors. However, functional trait research in epiphytic ferns is lagging behind, and we know little about how epiphytic ferns response to environmental variation and anthropological disturbance. In this study, from species to community level, the morphological, physiological and nutrient features of epiphytic ferns from a primary forest and its two-stage degraded forests of Ailao Mountans were measured and analyzed, to show the effect of forest degradation on epiphytic fern community, as well as the ecological strategies and response of epiphytic ferns during this course. The main results are as follows: (1) Both species diversity and functional diversity were affected by forestdegradation. In primary Lithocarpus forest, 31 species of epiphytic ferns and lycophytes were recorded in total, while only 20 and 16 respectively in Lithocarpus regrowth forest and Alnus nepalensis secondary forest in Xujiaba Region of Ailao Mountains. With thedegradation of forest, Shannon-Wiener index (H), Simpson index (D) and Evenness index (E) decreased. Furthermore, both Shannon-Wiener index and Simpson index were positively correlated with Rao’s quadratic entropy (FD) and community weighed mean (CWM) of functional traits. (2) The capacity of water conservation and carbon assimilation of epiphytic ferns varied across different growth stages, showing allometric relationships between most of the functional traits and plant biomass. At the early development stage of sporophyte,individuals with small plant biomass were more sensitive to the variation of water condition. They exhibited a high water loss rate and could be recovered from desiccation in a short time after rehydration, while with a relative low carbon assimilation capacity. With the increase of plant biomass, individuals of epiphytic ferns were more capable in water conservation, with relatively high carbon assimilation capacity. However, it would take longer time for them to be recovered from desiccation after rehydration. Thus, the inter- and intra-specific variation of morphological and physiological traits could be ascribed to the trade-offs between desiccation-related and economic traits. (3) Most of the functional traits of Lepisorus scolopendium, L. bicolor and Oleandra wallichii, three dominant epiphytic ferns in primary forests, varied along the vertical height gradient of canopy. Individuals of all species on the shade and humid tree trunk exhibited higher frond length, frond width, SLA, chlorophyll content and maximum photosynthesis rate, enable them to capture light more efficiency under low light condition.For individuals growing on upper canopy, they showed small and thick fronds with high succulence, which facilitated the water conservation at the cost of reduction in photosynthesis. (4) Lepisorus scolopendium and L. bicolor, two obligate epiphytic ferns in the primary forest, shifted to be facultative in secondary forests during forest degradation. The relative abundance of both species peaked at heights of approximately 8–16 m in the canopy of primary forest but at heights of 0–4 m on tree trunks in two degraded forests. Terrestrial individuals occurred only in secondary forests, and the relative abundance of these two species on lower tree trunk and forest ground increased with canopy openness within degraded forests. Functional traits of both species varied among different forests or between epiphytic and terrestrial habitats within the same secondary forests. Trade-offs between functional traits of these two species shaped different ecological strategies in resource utilization. Eipiphytic individuals were more capable in light capture, while those conspecifics exhibited higher capacity in photosynthesis and resource use efficiency; within the same secondary forest, terrestrial individuals trended to acclimate to low-light understory and were more efficient in their nutrient use than were epiphytic conspecifics.(5) The adventitious roots of Lepisorus scolopendium and L. bicolor were consisted of four order roots. After forest degradation, the number of root branching increased and shaped more lateral roots. Specifically, the increase of first and second order roots for terrestrial individuals demonstrated stronger capacity in nutrient and water absorption than those epiphytic ones. Roots of both species varied with shift in canopy openness and growth substrate during forest degradation, indicating different forage strategies of roots. Compared with morphological traits, the growth traits of roots were more responsible in the variation of forage strategies. In summary, at community level, forest degradation might lead to the decrease of species diversity and functional diversity, which would weaken the function and stability of the epiphytic fern community. At species level, high trait plasticity was adaptive at different growth stage and in the course of environment variation. By taking this, different ecological strategies were shaped, which facilitated them to make use of the limited resources in the environment and enhance the growth of the individuals. Key Words: Epiphytic ferns, Functional traits, Forest degradation, Environment variation, Subtropical moist forest

Language中文
Document Type学位论文
Identifierhttp://ir.xtbg.org.cn/handle/353005/11355
Collection西双版纳热带植物园毕业生学位论文
Recommended Citation
GB/T 7714
陈泉. 哀牢山湿性常绿阔叶林附生蕨类植物的功能性状及其对环境变化的响应[D]. 中国科学院西双版纳热带植物园. 中国科学院大学,2019.
Files in This Item:
File Name/Size DocType Version Access License
陈泉.pdf(6803KB)学位论文 开放获取CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[陈泉]'s Articles
Baidu academic
Similar articles in Baidu academic
[陈泉]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[陈泉]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.