山西植物功能型划分及其空间格局

随着全球气候变化的加剧,作为沟通陆地生态系统与气候变化的桥梁,植物功能型(Plant Functional Types,PFTs)越来越受到生态学家的关注。PFTs不仅是简化生态系统复杂性的有效工具,而且可将植物的生理生态过程、生物物理特征及物候变化等引入到动态植被模型中,研究气候变化下的植被反应及其反馈机制。为了在区域尺度上研究气候变化和植被反应,基于"生态-外貌"原则,依据植物特征(如生长型、叶的性状)及其对水分、温度的需求,结合区域的气候与地理条件,对山西植被进行植物功能型的划分,并在此基础上对其空间格局进行分析。结果表明:(1)山西植被可划分为19类植物功能型(其中包括4类栽培作物功能型),分别是:寒温性常绿针叶林、温性常绿针叶林、寒温性落叶针叶林、温性落叶阔叶林、高寒落叶灌丛、温性落叶灌丛、多年生禾草草原、多年生禾草草丛、多年生禾草草甸、多年生莎草草甸、多年生杂类草草原、多年生杂类草草丛、多年生杂类草草甸。1年生杂类草草甸、多年生豆科草原、果树、一年一熟栽培作物、一年二熟栽培作物和二年三熟栽培作物。植物功能型的划分和分布与山西植被区划有较好的一致性,基本反映了植物固有特征及其对水热条件的需求。(2)农作物在山西占有较大比重,占植被类型面积的53.15%,森林类型以温性常绿针叶林和温性落叶阔叶林为主,灌丛类型以温性落叶灌丛为主,草本类型中多年生禾草草丛占较大比例,占草本类型面积的50.98%。(3)由于水热条件及地理条件的差异,植物功能型(不考虑栽培作物)在各区域表现出较大差异,如多年生杂类草草原主要分布于北部地区,在南部并不存在这种植物功能型;森林类型的功能型主要分布于中、南部地区,且结构复杂、类型多样。(4)除栽培作物表现出较好的整体性和连通性,其他植物功能型均表现出不同程度的破碎化和离散化。(5)山西植物功能型整体上表现出较高的多样性,其中中部地区比其他地区的多样性和破碎化程度高,斑块类型更加趋向于离散的小斑块状,北部地区则以一年一熟栽培作物占明显优势,表现出较强的优势度,而南部地区并没有表现出很强的破碎度或优势度。

Classification of plant functional types and spatial pattern in Shanxi Province

Plant Functional Types (PFTs) have been paid increasing attention last decades as the linkage between terrestrial ecosystem and climate change with the intensification of global climate change. PFTs are not only an effective tool to simplify the complexity of ecosystem, but also helpful when exploring the response and feedback mechanism of plant to the climate changes by introducing plant physiological, ecological process, biophysical characteristics and phenological change into the vegetation dynamic model. In order to investigate climate change and response to vegetation at regional scale, PFTs classification system was proposed under the "eco-physiognomy" principle based on plant characteristics (such as vegetative form, leaf traits), thermal characteristics and water availability, combined with the regional climate and geographical conditions in Shanxi. Furthermore, the spatial pattern of PFTs was discussed in this paper. The results showed that: (1) Nineteen PFTs, including four PFTs of cultivated crops were identified, namely, cold warm-temperate evergreen coniferous forest, warm-temperate evergreen coniferous forest, cold warm-temperate deciduous coniferous forest, warm-temperate deciduous broadleaf forest, cold warm-temperate deciduous shrub, warm-temperate deciduous shrub, perennial grass steppe, perennial grass community, perennial grass meadow, perennial sedge meadow, perennial forbs steppe, perennial forbs community, perennial forbs meadow, annual forbs meadow, perennial Legume steppe, fruit tree, one crop per annual, two crop per annual, and three crop two annual. The classification and distribution of plant functional types reflect the inherent characteristics and demand for water and thermal of plants, being consistent with vegetation regionalization of Shanxi Province. (2) Crops are dominant in Shanxi, accounting for 53.15% of the total vegetation type area. Forest and shrubs types are dominated by warm-temperate evergreen coniferous forest, warm-temperate deciduous broadleaf forest and warm deciduous shrubs, respectively. Perennial grass community occupies a large proportion, accounting for 50.98% of the total area of the herbaceous types. (3) PFTs (except for crop cultivation) show bigger difference in different regions due to hydrothermal and geographical conditions. For example, perennial forbs steppe mainly distributed in north Shanxi, rather than in the south Shanxi. Compared with north Shanxi, the functional types of forest mainly distributed in the central and south Shanxi, and its structure and types were complex and diverse. (4) The cultivation crops show good integrity and connectivity, while the other PFTs show the fragmentation and discretization. (5) PFTs of Shanxi show integrally high diversity. Compared with the other two parts, more fragmentation and higher diversity are found in the central Shanxi. One crop per annual mainly distributed in North Shanxi, while south Shanxi did not exhibit significant fragmentation and dominance.