Use of Summer Precipitation Along a Summer Precipitation Gradient

这个建议是针对了解共同的能力， 干旱地区植物利用夏季降水事件和 不同水源对生长的影响 干物质生产效率。 初步数据显示 山间的几种主要多年生植物 西部似乎没有利用夏季降水，即使夏季 雨水是每年水输入的主要组成部分， 生态系统 建议检查几个假设相关 植物对夏季降水的利用， 涉及生物质生产的效率，沿着 增加夏季降水。 研究将集中在 使用稳定同位素分析来确定水源和 干物质生产效率。 实地研究将 在五个地点进行，夏季从15%到52%不等 降水量，但总的来说， 降水和温度。 本研究将重点关注显性 荒漠过渡带乔木-亚乔木树种 和温带森林生态系统：杜松（Juniperus osteosperma）， 松树（Pinus edulis）和矮栎（Quercus gambelii）。 那里 在拟议研究的应用方面具有很大的潜力。 稳定同位素分析提供了综合的长期估计， 涉及水分利用和干物质效率的植物参数 生产 从本研究中获得的信息和技术 将有助于确定要使用的字符类型 用于评价森林木材和纸浆品种。 林农和 农学家已经开始使用这些稳定同位素 不同遗传系的综合分析方法。

This proposal is directed at understanding the ability of common arid region plants to utilize summer precipitation events and the consequences of different water sources for growth and for the efficiency of dry matter production. Preliminary data indicate that several of the dominant perennial species in the Intermountain West appear not to utilize summer precipitation, even though summer rain is a major component of the annual water input to these ecosystems. It is proposed to examine several hypotheses related to a plant's utilization of summer precipitation and how this relates to the efficiency of biomass production along a gradient of increasing summer precipitation. Research will be centered on using stable isotope analyses to determine both water sources and efficiency of dry matter production. Field studies will be conducted at five sites, which range from 15% to 52% summer precipitation, but which are otherwise similar in total precipitation and temperature. The study will focus on dominant tree-subtree species in the ecosystem transitional between desert and temperate forest ecosystems: Juniper (Juniperus osteosperma), pinyon pine (Pinus edulis) and scrub oak (Quercus gambelii). There is strong potential for applied aspects of the proposed research. Stable isotope analyses provide integrated long-term estimates of plant parameters involving water use and efficiency of dry matter production. The information and techniques derived from this study will be useful in determining the kinds of characters to be used for evaluation of forest timber and pulp species. Foresters and agronomists are already beginning to use these stable isotope approaches for integrated analyses of different genetic lines.