Kadmon Ronen, Shmida Avi
Department of Botany, Institute of Life Sciences, The Hebrew University, 91904, Jerusalem, Israel.
Oecologia. 1990 May;83(1):139-144. doi: 10.1007/BF00324645.
This study examines patterns and causes of variation in the reproductive success of the desert annual Stipa capensis. Three nested scales of variation were analyzed: variation between individuals of the same plot, variation between different plots of the same habitat, and variation between different habitats in the same region. Perturbation experiments (irrigation and neighbors removal) were performed to test the effects of heterogeneity in soil water and neighborhood competition on the magnitude of variation in each scale. The results demonstrate that variation of reproductive success was highest within plots, lowest between plots, and moderate between habitats. Soil water heterogeneity contributed to spatial variation in all scales but was most important for differences between habitats. Neighborhood competition increased the variation within plots, but decreased the variation between habitats. The results further demonstrate that water limitation was negatively correlated with the position of the habitat along the run-off/run-on gradient. An opposite trend was obtained for the effect of competition.
本研究考察了沙漠一年生植物尖稃针茅繁殖成功率的变化模式及成因。分析了三个嵌套的变异尺度：同一块地内个体间的变异、同一栖息地不同地块间的变异以及同一区域不同栖息地间的变异。进行了扰动实验（灌溉和去除邻体），以测试土壤水分异质性和邻体竞争对各尺度变异程度的影响。结果表明，繁殖成功率的变异在地块内最高，在地块间最低，在栖息地间适中。土壤水分异质性导致了所有尺度的空间变异，但对栖息地间的差异最为重要。邻体竞争增加了地块内的变异，但减少了栖息地间的变异。结果还表明，水分限制与栖息地沿径流/入流梯度的位置呈负相关。竞争效应则呈现相反的趋势。
