Microenvironmental and vegetational heterogeneity induced by phytogenic nebkhas in an arid coastal ecosystem
Microenvironmental and vegetational heterogeneity induced by phytogenic nebkhas in an arid coastal ecosystem
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DOI：
10.1023/a:1021548711206
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发表时间：
2002-12-01
期刊：
影响因子：
4.9
通讯作者：
Kockelbergh, F
中科院分区：
文献类型：
--
作者：
El-Bana, MI;Nijs, I;Kockelbergh, F
木本植物的内布哈斯代表了干旱和半干旱生态系统中不同的栖息地。 Nebkhas 是由灌木冠层内部或周围的风载沉积物组成的土丘。我们研究了西奈半岛地中海沿岸分布广泛的 Retama raetam 灌木丛对其微环境和相关草本植被的影响。我们的测量包括内布卡尺寸（高度和宽度）和灌木尺寸（树冠高度和直径）。我们在每个 Nebkha 处确定了四个不同的微地点：顶部、中坡、边缘和 Internebkha 空间。我们测量了土壤温度和湿度、光合有效辐射 (PAR) 和土壤特性。鉴定了每个微站点生长的植物种类并测量了它们的密度。平均土壤温度和 PAR 在 internebkha 空间最高，在 nebkha 山顶最低。 Internebkhas 的最高日气温和 PAR 均超过 Nebkhas。土壤水分和养分浓度表现出空间异质性梯度，并且在内布卡边缘最高。回归分析表明，草本植物总密度与内布哈大小、灌木冠层直径和面积显着相关。去趋势对应分析表明，物种组成模式与土壤湿度和养分含量沿距内布卡峰距离增加的梯度的空间变异相关。据推测，灌木冠层及其内层在控制该环境中的生态系统功能方面相互作用。
The nebkhas of woody plants represent distinct habitats in arid and semiarid ecosystems. Nebkhas are mounds composed of wind-borne sediment within or around shrub canopies. We studied the effects of widely spaced nebkhas of Retama raetam shrub on their microenvironment and associated herbaceous vegetation in the Mediterranean coast of Sinai Peninsula. Our measurements included nebkha size (height and width) and shrub size (canopy height and diameter). We identified four distinct microsites at each nebkha: crest, mid-slope, edge, and internebkha space. We measured soil temperature and moisture, photosynthetically active radiation (PAR), and soil properties. The plant species grown at each microsite were identified and their densities were measured. Average soil temperature and PAR were highest at internebkha space and lowest at nebkha crest. The maximum diurnal temperature and PAR of internebkhas exceeded that of nebkhas. Soil moisture and nutrient concentrations showed a gradient of spatial heterogeneity and were highest at the nebkha edge. Regression analysis indicated that total herbaceous plant density was significantly related to nebkha size, and to shrub canopy diameter and area. Detrended correspondence analysis indicated that patterns of species composition were correlated with the spatial variability in soil moisture and nutrient content along the gradient of increasing distance from the nebkha crest. It is assumed that shrub canopy and its nebkha interact in governing ecosystem functioning in this environment.