DISSERTATION RESEARCH: Between a tree and a dry place - How competition and drought tolerance constrain tree geographic ranges

论文研究：在一棵树和一个干燥的地方之间 - 竞争和耐旱性如何限制树木的地理范围

• 批准号: 1500837
• 负责人: Janneke Hille Ris Lambers
• 金额: $ 1.63万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1500837&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Between; tree; dry

Identifying the main constraints on species ranges and how these constraints vary across the globe has proven remarkably difficult; the degree to which the environment alone or in combination with interactions with other organisms imposes the limit is the crux of the problem. This project will combine experiments, field studies, and species distribution models to test whether plant species along a gradient from dry to wetter environments are squeezed between death from drought on one side of their range and fierce competition with species adapted to wetter conditions on the other. The results can help explain when, where, and how tree range boundaries are constrained, thereby advancing the state of the science. Such information may help guide land managers who seek to prepare for a rapidly changing climatic future by suggesting which conservation and forecasting tools are relevant in what situations, and thus enhances national welfare. It will also improve science education through activities for high school students.It has long been hypothesized that plants are constrained by a fundamental trade-off between competitive ability and environmental stress tolerance, because adaptations to tolerate stress are energetically costly and limit maximum growth rates. Using seedling experiments, dendrochronological techniques, and species distribution modeling, this project explores whether tree species inhabiting aridity gradients in the U.S. and Australia show a trade-off between fast growth (a proxy for competitive ability) and drought tolerance. It then tests whether this trade-off mirrors growth constraints on adult trees in the field, and whether the observed trade-off and/or systematic growth constraints explain species turnover across aridity gradients. For broader impacts a module based on this research will be developed and piloted in cooperation with high school teachers, and results will be communicated to the public through a university teaching greenhouse.

确定物种分布范围的主要限制因素以及这些限制因素在地球仪上的变化已被证明是非常困难的;环境本身或与其他生物相互作用的结合对限制的程度是问题的关键。这个项目将结合联合收割机实验，实地研究和物种分布模型，以测试植物物种沿着梯度从干燥到潮湿的环境是否被挤压之间的干旱死亡在其范围的一边和激烈的竞争，适应潮湿的条件下的其他物种。这些结果可以帮助解释何时、何地以及如何限制树木的范围边界，从而推进科学的发展。这些信息可以帮助指导土地管理者，他们试图为未来迅速变化的气候做好准备，建议在何种情况下使用何种养护和预测工具，从而提高国家福利。长期以来，人们一直假设植物受到竞争能力和环境压力耐受力之间的基本权衡的限制，因为适应压力的适应需要消耗大量的能量，并限制了最大的生长速度。利用幼苗实验，树木年代学技术和物种分布模型，该项目探讨了在美国和澳大利亚居住在干旱梯度的树种是否表现出快速增长（竞争能力的代理）和耐旱性之间的权衡。然后，它测试这种权衡是否反映了在该领域的成年树木的生长限制，以及所观察到的权衡和/或系统的生长限制是否解释了物种的营业额跨越干旱梯度。为了产生更广泛的影响，将与高中教师合作开发和试行一个基于这项研究的模块，并将通过大学教学温室向公众传达结果。