Responses of woody species to spatial and temporal ground water changes in coastal sand dune systems
Responses of woody species to spatial and temporal ground water changes in coastal sand dune systems
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DOI：
10.5194/bg-8-3823-2011
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发表时间：
2011-12
期刊：
影响因子：
4.9
通讯作者：
C. Máguas;K. Rascher;A. Martins-Loução;P. Carvalho;P. Pinho;M. Ramos;O. Correia;C. Werner
中科院分区：
文献类型：
--
作者：
C. Máguas;K. Rascher;A. Martins-Loução;P. Carvalho;P. Pinho;M. Ramos;O. Correia;C. Werner
抽象的。尽管地下水在沿海沙丘系统的相对重要性，植被对地下水（GW）的可用性变化，特别是在地中海地区的响应的研究，是稀缺的。因此，本研究的主要目的是比较具有不同功能性状的共生物种，在沙丘生态系统中的GW水平的变化（即GW水平的降低）的反应。为此，在地中海中部以松树林为主的沙丘生态系统的1平方公里范围内建立了5个站点。由于自然地形的变化和人为的GW开发，大量的变化，深度GW网站之间被发现。在这些条件下，它是可能的，以确定不同的植物物种（两个深根树木，干旱适应灌木，潜水植物和非本地木本入侵者）的使用和依赖GW的程度，以及如何GW的依赖性随季节变化和异质性网站之间。结果表明，植物物种有不同的反应，GW深度的变化，根据特定的功能性状（即生根深度，叶形态，和水分利用策略）。种间比较结果表明，深根（Pinus pinaster，Myrica faya）和潜生（Salix repens）种的黎明前水势和叶片δ 13 C的变异与GW利用的立地差异有关。但是，这种变化在春季比夏季干旱更明显。外来入侵者，长叶金合欢，这并不具有很深的根系，表现出最大的季节性变化的前叶和散装叶δ 13 C。与此相反，Corema album，一种特有的林下干旱适应灌木的反应，似乎是独立的跨季节和网站的水的可用性。因此，由于人为开采，在植物物种从沙丘，降低GW的敏感性是可变的，是特别相关的深根物种和潜水植物，这似乎在很大程度上依赖于访问GW。
Abstract. In spite of the relative importance of groundwater in costal dune systems, studies concerning the responses of vegetation to ground water (GW) availability variations, particularly in Mediterranean regions, are scarce. Thus, the main purpose of this study is to compare the responses of co-occurring species possessing different functional traits, to changes in GW levels (i.e. the lowering of GW levels) in a sand dune ecosystem. For that, five sites were established within a 1 km2 area in a meso-mediterranean sand dune ecosystem dominated by a Pinus pinaster forest. Due to natural topographic variability and anthropogenic GW exploitation, substantial variability in depth to GW between sites was found. Under these conditions it was possible to identify the degree of usage and dependence on GW of different plant species (two deep-rooted trees, a drought adapted shrub, a phreatophyte and a non-native woody invader) and how GW dependence varied seasonally and between the heterogeneous sites. Results indicated that the plant species had differential responses to changes in GW depth according to specific functional traits (i.e. rooting depth, leaf morphology, and water use strategy). Species comparison revealed that variability in pre-dawn water potential (Ψpre) and bulk leaf δ13C was related to site differences in GW use in the deep-rooted (Pinus pinaster, Myrica faya) and phreatophyte (Salix repens) species. However, such variation was more evident during spring than during summer drought. The exotic invader, Acacia longifolia, which does not possess a very deep root system, presented the largest seasonal variability in Ψpre and bulk leaf δ13C. In contrast, the response of Corema album, an endemic understory drought-adapted shrub, seemed to be independent of water availability across seasons and sites. Thus, the susceptibility to lowering of GW due to anthropogenic exploitation, in plant species from sand dunes, is variable, being particularly relevant for deep rooted species and phreatophytes, which seem to depend heavily on access to GW.