Consequences of Drought for Populations of Cryptantha flava

小行星9527833 根据预测全球气候长期变化的模型，半沙漠地区预计将变得更加干燥。 这项研究的目的是预测这些地区的植物自然种群将如何应对干旱条件。 大多数植物水分利用的生态学研究 有 专注于解剖学 或 使特定物种能够占据干燥的栖息地的生理适应。 在确定人口和社区将如何应对水供应的时间变化方面，几乎没有做出努力。 要做到这一点，我们需要了解干旱如何影响个体，这取决于它们的大小，发育阶段或与其他植物的关系。 研究人员将通过在春季暴雨期间建立临时避难所来实验性地减少半沙漠草本多年生植物Cryptantha flava的自然种群所接受的降雨量。 这项研究是根据在自然干旱年份收集的数据进行的，这些数据表明，较大的植物比较小的植物受到干旱的影响更严重。 将对不同大小和不同微生境中的个体的生存、生长和开花情况进行比较，这些微生境包括灌木丛下或开阔地，无论是在水量减少的地区还是在接受自然降雨的地区。 这些人口统计数据将通过测量用水量、叶片氮含量和光合作用来补充。 这些测量将有助于确定为什么个人会对水资源的变化做出反应。 减少水的实验将在两个不同的年份重复进行。 在干旱前一年、干旱年和干旱后一年，将对同一个体进行人口统计学和生理学测量。 这种重复实验很重要，因为在实验过程中很可能发生降雨的自然变化。 这项研究还应有助于查明干旱年份本身以外的长期影响。

9527833 Casper Under models that predict long-term changes in global climate, semi-desert regions are expected to become even drier. The purpose of this study is to predict how natural populations of plants in these regions will respond to drought conditions. Most ecological studies of water use in plants have focused on anatomical or physiological adaptations that allow particular species to occupy dry habitats. There has been little effort to determine how populations and communities will respond to temporal changes in water availability. To do this, we need to understand how drought affects individuals depending on their size, developmental stage, or associations with other plants. The investigators will experimentally reduce the amount of rainfall received by natural populations of the semi-desert herbaceous perennial Cryptantha flava by erecting temporary shelters during spring rainstorms. The study is based on data collected during a natural drought year indicating that larger plants are more severely affected by drought than smaller plants. Comparisions will be made of survival, growth and flowering of individuals of different sizes and in different microhabitats, under shrubs or in the open, both in areas where water has been reduced and in areas receiving natural rainfall. These demographic data will be supplemented by measurements of water use, leaf nitrogen content, and photosynthesis. These sorts of measurements will help to determine why individuals respond to changes in water availability as they do. The experimental reduction in water will be repeated spatially and in two different years. Demographic and physiological measurements will be taken on the same individuals in the year before drought, the drought year, and the year afterwards. This replication of the experiment is important because natural variation in rainfall is likely to occur during the experiment. The study should also lead to identification of lingering effects that extend beyond the drought year itself.