SGER: Comparative Demography of Desert Plants Following El Nino

摘要：要理解自然景观为什么是这样的，就需要理解植被是如何对异常事件做出反应的。在南加州的沙漠中，雨水通常只在冬季出现；然而，偶尔会有不寻常的夏末风暴从南方袭来。在过去的25年里，有两次这样不寻常的夏季事件：1976年的飓风凯瑟琳和1997年的飓风诺拉。作为对这些事件的回应，种子发芽的物种通常没有新的增加到他们的种群。种子发芽只是向种群中添加新植物的第一步；他们也必须生存下去。飓风凯萨琳过后的冬季相对干燥，幼苗死亡率高。1997年到1998年的冬天正处于厄尔尼诺现象期间，天气更加湿润。在一场不寻常的夏季飓风之后，伴随着厄尔尼诺现象的冬季强降雨，种子发芽可能会成为沙漠中许多植物物种本世纪最重要的事件。我们对幼苗生长和存活的研究将有助于理解生态系统中罕见事件的重要性。

Abstract 9810414 Ebert Understanding why natural landscapes look as they do requires understanding how vegetation responds to unusual events. In the desert of southern California, rain typically is confined to winter months; occasionally, however, unusual late summer storms sweep up from the south. During the past 25 years there have been two of these unusual summer events: Hurricane Kathleen in 1976 and Hurricane Nora in 1997. In response to these events, seeds germinated for species that usually do not have new additions to their populations. Germination of seeds is just the first step in adding new plants to a population; they also must survive. The winter following Hurricane Kathleen was relative dry and seedling mortality was high. The winter of 1997-98 is during an El Nino and is proving to be much wetter. Seed germination following an unusual summer hurricane followed by high winter rains associated with an El Nino may prove to be the most important event of this century for many plant species in the desert. Our study of seedling growth and survival will help to understand the importance of rare events in ecosystems.