Horizontal and vertical distribution of desert seed banks: patterns, causes, and implications
Horizontal and vertical distribution of desert seed banks: patterns, causes, and implications
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DOI：
10.1006/jare.1997.0353
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发表时间：
1998-03-01
影响因子：
2.7
通讯作者：
Goodall, DW
中科院分区：
文献类型：
--
作者：
Guo, QF;Rundel, PW;Goodall, DW
这项研究使用相同的技术和同一组观察者在北美沙漠的四个地点（犹他州大盆地沙漠的柯卢谷；莫哈韦沙漠的内华达州洛克谷；索诺兰沙漠的亚利桑那州银铃；以及奇瓦瓦沙漠的新墨西哥州乔纳达）调查了小规模种子的分布情况。水平（灌木冠层下到开放区域）和垂直（在土壤表面和四个深度间隔测量）分布模式与种子形态的关系进行了检查。在所有四个地点，单个物种的种子分布与种子丰度呈正相关。水平方向上，从灌木冠层下到灌木间区域，每单位面积的种子总数减少。在垂直方向上，种子总数随着土壤深度的增加而下降。大多数物种仅存在于一小部分样本中。小种子要么丰富且分布广泛，要么很少见，仅在少数样本中发现，但较大种子的丰度总是较低，并且仅限于一小部分样本。对于一年生物种，在土壤深处发现的较大种子的比例明显高于较小种子。然而，当分析中包括较大种子的物种，即多年生草本植物和灌木时，大多数非常小或非常大的种子出现在土壤的最上层，而中等到大尺寸的种子则出现在土壤深处。这种与种子形态和土壤因素相关的种子分布可能对沙漠生态系统的植物种群动态和群落结构具有重要的生态意义。 (C) 1998 学术出版社有限公司。
This study examined small-scale seed distribution using published data collected using the same techniques and the same group of observers in four locations in North American deserts (Curlew Valley, Utah in the Great Basin Desert; Rock Valley, Nevada in the Mojave Desert; Silverbell, Arizona in the Sonoran Desert; and Jornada, New Mexico in the Chihuahuan Desert). The distribution patterns were examined horizontally (under shrub canopy to open areas) and vertically (measured at the soil surface and at four depth intervals) in relation to seed morphology. At all four sites, seed distribution of individual species was positively related to seed abundance. Horizontally, total number of seeds per unit area decreased from under the shrub canopy to intershrub areas. Vertically, total number of seeds declined as soil depth increased. Most species were only present in a small proportion of samples. Small seeds were either abundant and broadly distributed or rare and found in a few samples, but larger seeds were always low in abundance and restricted to a small proportion of samples. For annual species, significantly higher proportions of larger seeds than smaller seeds were found deeper in the soil. However, when much larger-seeded species, i.e. herbaceous perennials and shrubs, were included in the analyses, most very small or very large seeds were found in the upper-most layers of soils and intermediate to large-sized seeds deeper in the soils. Such seed distribution related to seed morphology and soil factors may have significant ecological implications in plant population dynamics and community structure in desert ecosystems. (C) 1998 Academic Press Limited.