LTREB: The Population and Community Dynamics of Desert Winter Annuals

这项研究将调查索诺兰沙漠一年生植物的动态，以确定这些植物如何适应不可预测的环境。 沙漠一年生植物已被用来研究在高度可变的环境中的群落动态，但种子萌发和传播的动态，被认为是持久性和共存的主要决定因素还不为人所知。 这项研究将继续并扩展亚利桑那大学沙漠实验室（前身为卡内基沙漠研究实验室，自1903年成立并持续运营）沙漠冬季一年生植物种群和群落动态的12年数据集。 由于长寿命休眠种子的生产被认为是一个重要的功能，使沙漠一年生植物坚持通过不利的条件下，他们将确定种子库每年发芽的种子的比例，并在该领域的自然和实验种子库构建消耗曲线。 此外，将进行田间试验，以测量种子传播距离。 田间和实验室发芽实验将描述种子休眠机制。 最后，物种对天气变化的反应将被构建并用于计算机模拟休眠和扩散以及方差介导的物种共存的演变。 了解沙漠一年生植物的动态将提高我们对沙漠生态系统的认识，因为一年生植物是沙漠动物所依赖的初级生产力的一个主要和高度可变的组成部分。 全球荒漠化正在经历地理边界的变化。 由于一年生植物对天气变化反应迅速，因此对沙漠一年生植物的长期监测还应提供对全球变暖和气候变化的生物影响的独特评估。

This research will investigate the dynamics of Sonoran Desert annual plants in order to determine how these plants adapt to unpredictable environments. Desert annuals have been used to study community dynamics in highly variable environments yet the dynamics of seed germination and dispersal, considered primary determinants of persistence and coexistence are not well known. This research will continue and extend a 12 year data set on the population and community dynamics of desert winter annual plants at the Desert Laboratory of the University of Arizona (formerly the Carnegie Desert Research Laboratory founded and in continuous operation since 1903). Since the production of long-lived dormant seeds is considered to be an important feature permitting desert annuals to persist though unfavorable conditions they will determine the fraction of seeds the seed bank germinating each year and construct depletion curves for both natural and experimental seed banks in the field. Also, field experiments will be conducted to measure seed dispersal distances. Field and laboratory germina tion experiments will describe seed dormancy mechanisms. Finally, species responses to weather variation will be constructed and used in computer simulations of the evolution of dormancy and dispersal and variance-mediated species coexistence. Understanding the dynamics of desert annuals will improve our knowledge of desert ecosystems, since annuals represent a major and highly variable component of primary productivity on which the desert animals depend. Deserts worldwide are undergoing shifts in geographic boundaries. Since annual plants respond quickly to weather shifts, the long-term monitoring of desert annuals should also provide a unique assessment of the biotic impacts of global warming and climate change.