延河流域森林草原区不同植物功能型适应策略及功能型物种数量随退耕年限的变化

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 延河流域森林草原区不同植物功能型适应策略及功能型物种数量随退耕年限的变化 DOI: 10.5846/stxb201310222548 作者: 作者单位: 西北农林科技大学资源环境学院,西北农林科技大学水土保持研究所,西北农林科技大学资源环境学院,西北农林科技大学资源环境学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(41271297); 中国科学院重要方向项目(KZCX2-EW-406) Adaptation strategies of different plant functional types and their composition along a vegetation restoration gradient in a forest-steppe zone in the Yanhe River catchment, Shaanxi, China Author: Affiliation: College of Resources and Environment,Northwest A F University,Yangling,Shannxi,Institute of Soil and Water Conservation, Northwest A&F University, Ningbo, Yangling, Shannxi, 712100, China,College of Resources and Environment,Northwest A F University,Yangling,Shannxi,College of Resources and Environment,Northwest A F University,Yangling,Shannxi Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:不同退耕年限退耕地的环境差异以及不同生物间的相互作用导致各阶段植物功能型物种数量不同。研究退耕地植被自然恢复过程中不同植物功能型适应策略及功能型物种数量随退耕年限的变化,对于理解植物对环境的响应机制及植物的适应策略具有重要意义。采用空间序列代替时间序列的方法,以延河流域森林草原区不同退耕年限、自然恢复的植物群落为研究对象,调查了不同退耕年限的植物群落33 个,共44 种植物,涉及16 个科35 个属,分别测定了每个物种的叶厚度、比叶面积、叶组织密度、叶片氮含量、比根长、根组织密度、细根氮含量等7 项能够反映植物生存对策且易于测量的功能性状。依据这7 项植物功能性状,采用数量分类方法将全部物种划分为3 个功能型。结果表明:(1)根据C-S-R理论,功能型Ⅰ植物用于防御的投资较多,生长速率处于中间水平,偏向于"胁迫-干扰型",功能型Ⅱ植物能够通过维持体内的养分平衡的方式对抗资源贫瘠或干旱的环境,偏向于"胁迫-竞争型"对策,而功能型Ⅲ植物吸收大量的营养和资源用于生长,偏向于"竞争型";(2)功能型Ⅰ在整个植被恢复时间序列中占据优势地位(61%-80%),并呈增加趋势,功能型Ⅱ则由恢复初期的25%降低为恢复后期的15%,功能型Ⅲ从恢复初期的14%降低到恢复后期的5%。同时,在功能型Ⅰ内部,优势物种也发生着相应的相互替代。虽然土壤养分含量整体上随着植被自然恢复时间的延长而呈上升趋势,但是植物的生存环境并未改善到不存在干扰与胁迫的程度。因此,在植被恢复初期的四、五十年内,"胁迫-干扰型"策略的植物占据着绝对优势。随着植被恢复时间的延长,能够高效利用资源且抗胁迫能力强的物种代替了以快速生长和传播为适应策略的物种。 Abstract:Ecological success under different environmental conditions and interactions among organisms may require plants to share certain common functional traits, allowing for the classification by plant functional type (PFT). The objective of this study was to explore the adaptation strategies of different PFTs and the change in number of species in each type along a vegetation restoration gradient in a forest-steppe zone in the Yanhe River catchment, Shaanxi, China. We placed emphasis on PFT dynamics and variations during vegetation restoration of an abandoned farmland in this area. Our goal was to provide helpful information to better understand how plant adaptation strategies change as vegetation restoration progresses. This study used a spatial sequence approach instead of a temporal sequence one. We measured four leaf traits (thickness [LT], specific area [SLA], tissue density [LTD], and nitrogen concentration per unit mass [LN]) and three fine root traits (specific length [SRL], tissue density [RTD], and nitrogen concentration per unit mass [RN]) for each of the 39 species belonging to 16 families in 33 plant communities across five vegetation restoration stages in a forest-steppe zone in the Yanhe River catchment. All species were classified into one of the three PFTs based on the seven functional traits using cluster analysis. One-way analysis of variance was used to describe the variation among the PFTs. We then analyzed adaptation strategies for each PFT and compared the changes in the functional type composition along with the vegetation restoration stages. The results showed the following. (1) Based on the seven functional traits, which showed large variations across all 39 species, the plants were classified into three functional types (PFTI-Ⅲ). (2) Plants in PFT-Ⅰ had higher LTD and lower LT, LN, and RN; plants in PFT-Ⅱ had higher RTD, LN, and RN, and 39 species showed large variation. (3) Plants in PFT-Ⅰ had higher LTD and lower LT, LN, and RN; plants in PFT-Ⅱ had higher RTD, LN, and RN and lower SLA and SRL; and plants in PFT-Ⅲ had larger LT, SLA, and SRL and lower LTD and RTD. (4) According to the C-S-R triangle theories of Grime, PFT-Ⅰ, which invested more energy in defense and had an intermediate growth rate, adopted the "stress tolerance-ruderals" strategy. PFT-Ⅱ adopted the "stress tolerance-competitiveness" strategy, which allows survival in resource-poor environments by maintaining the nutrient balance in the body. PFT-Ⅲ devoted large quantities of nutrients to growth and belonged to the "competitiveness" strategy. (5) PFT-Ⅰ was dominant in all vegetation restoration stages and increased in prevalence across the vegetation restoration gradient (from 61% to 80%), while the percentage of PFT-Ⅱ decreased from 25% to 15% and that of PFT-Ⅲ from 14% to 5%. The dominant species within PFT-Ⅰ also changed over time. SLA of the dominant species in PFT-Ⅰ decreased markedly, and LN and RN of the dominant species in the early restoration period were bigger than in later stages. Although the nutrient content of the soil increased along the restoration gradient, the environment has not been sufficiently improved to eliminate stress during the 40 or 50 years of early vegetation restoration. Thus, PFT-Ⅰ, with adaptation strategies favoring stress tolerance over rapid growth, were dominant. These results may help guide species selection and restoration planning. 参考文献 相似文献 引证文献