Population Dynamic Consequences of Dispersal and Between-year Dormancy

已经建立了理论模型来研究延迟发芽和种子传播对植物在可变环境中的生态和进化的影响。这些模型表明，休眠和扩散是应对和利用环境变化的重要机制。然而，由于难以量化种子传播和休眠的种群动态，实际上没有对这些模型进行实验校准或在自然种群中对其预测进行测试。新的研究将应用新的程序，这有助于估计植物种群的扩散和延迟发芽的大小，以确定生境内繁殖、年间种子库和种子传播在沙漠一年生植物自然种群中的相对重要性。这项研究将在亚利桑那大学的沙漠实验室进行，该实验室拥有最古老的正在进行的沙漠植物永久性研究，88年的准确天气数据，以及9年的拟议研究生物的人口统计数据。荒漠化和人类对自然生态系统不断增加的干扰现在已经司空见惯。重要的是要知道，我们关于变异的生态和进化后果的理论概念在多大程度上实际上可以预测自然界发生的事情。就沙漠一年生植物而言，沙漠地区的植物区系中有很大一部分是一年生植物（通常为30-100%）。对它们的生命周期、生态和进化的调查不仅为一般认识提供了基础，而且可能为它们的保护和合理利用（例如在干旱土地放牧）提供一些见解。

Theoretical models have been developed to investigate the consequences that delayed germination and seed dispersal have for the ecology and evolution of plants in variable environments. These models suggest that dormancy and dispersal are important mechanisms for coping with, and exploiting environmental variation. There has been, however, virtually no experimental calibration of those models or tests of their predictions in natural populations due to the difficulty of quantifying the population dynamics of seed dispersal and dormancy. New research will apply new procedures, which facilitate the estimation of the magnitudes of dispersal and delayed germination for plant populations, to determine the relative importance of within- habitat reproduction, between-year seed bank, and seed dispersal in natural populations of desert annuals. The study will be performed at the Desert Laboratory of the University of Arizona, which has the oldest ongoing permanent plot studies of desert plants, 88 years of accurate weather data, and 9 years of demographic data collected on the proposed study organisms. Desertification and increasing levels of human disturbance to natural ecosystems are now commonplace. It is important to know to what extent our theoretical concepts regarding the ecological and evolutionary consequences of variation are actually predictive of what goes on in nature. With specific respect to desert annuals, a large fraction of the flora of desert regions are annual plants (frequently 30-100%). Investigations of their life-cycles, ecology and evolution not only provide a basis for general understanding, but may provide some insights regarding their conservation and rational exploitation (e.g. in arid land grazing).