The demographic role of soil seed banks.: II.: Investigations of the fate of experimental seeds of the desert mustard Lesquerella fendleri
The demographic role of soil seed banks.: II.: Investigations of the fate of experimental seeds of the desert mustard Lesquerella fendleri
复制标题
DOI：
10.1046/j.1365-2745.2000.00444.x
复制
发表时间：
2000-04-01
影响因子：
5.5
通讯作者：
Mitchell, RJ
中科院分区：
文献类型：
--
作者：
Cabin, RJ;Marshall, DL;Mitchell, RJ
1尽管对种子的研究和了解很少，但种子在扩散后的运动和命运可能严重影响植物群落的后续结构，特别是在沙漠生态系统中，种子可能是许多植物物种中最丰富的或唯一可存活的形式。我们通过检查种子的传播和捕食，以及通过量化种子在新墨西哥州沙漠灌木丛中三个不同地点萌发和存活的种子的比例来调查沙漠芥菜实验种子的命运。2我们发现啮齿动物对种子的传播非常有限，但对种子的捕食具有很强的密度依赖性。土壤种子萌发率和幼苗成活率在试验结束时存在显著且一致的微位效应。我们没有发现土壤种子持久性的一致微位效应，但确实发现土壤种子持久性与土壤种子萌发呈正相关。总体而言，这些结果表明，种子捕食可能强烈影响种子库的分布，非生物环境可能在很大程度上决定土壤种子种群反过来影响新兴表面植物分布的程度。3我们提出了一个种子命运模型，该模型综合了莱斯克雷氏菌研究系统目前和以前的经验调查结果。这张图说明了非生物环境、微站点变异和种子基因型之间的相互作用如何决定哪些土壤种子成功萌发并形成表层植物种群。我们认为，沙漠表面植物种群的人口统计学可能更多地取决于种子投入和这些种子在土壤中的寿命之间的时间，而不是任何一个时间点和空间点产生的种子数量。
1 Although poorly studied and understood, the post-dispersal movements and fates of seeds may affect critically the subsequent structure of plant communities, particularly in desert ecosystems where seeds can be the most abundant or only viable form of many plant species. We investigated the fate of experimental seeds of the desert mustard Lesquerella fendleri by examining seed dispersal and predation, and by quantifying the proportion of seeds that germinated and survived as seedlings in three different microsites within a New Mexico desert shrubland.2 We found very limited seed dispersal but strong density-dependent seed predation by rodents. There was a significant and consistent microsite effect in the proportion of soil seeds germinating and seedlings surviving to the end of the experiments. We did not find a consistent microsite effect for soil seed persistence, but did find a positive correlation between soil seed persistence and soil seed germination. Overall, these results indicate that seed predation may strongly affect the distribution of the seed bank, and that the abiotic environment may largely determine the extent to which soil seed populations in turn affect the distribution of emerging surface plants.3 We present a seed fate model that synthesizes the results of the present and previous empirical investigations of the Lesquerella study system. This diagram illustrates how interactions among the abiotic environment, microsite variation and seed genotypes can determine which soil seeds successfully germinate and establish into the surface plant population. We suggest that the demography of desert surface plant populations may depend more on the time between seed inputs and the longevity of these seeds in the soil than on the amount of seeds produced at any one point in time and space.