Responses of Andean Montane Forests to Climate Change

热带安第斯森林拥有地球上最高的植物多样性。目前的变暖速度比美国其他地方高出三倍。美国参考因此，气候变化加上低地物种的入侵性迁移，对今后山地森林的多样性和功能构成重大挑战。因此，热带安第斯山脉是一个高度优先的地区，在那里研究热带树木适应其光合作用的潜力，以适应温度的变化。现在有证据表明，在一些高海拔树种的暖缘范围收缩，这表明了对最近变暖的强烈反应。因此，为了大大推进对安第斯热带森林生产力今后将如何变化的预测，并评估对生物多样性的影响，确定物种范围的变化是否与生理适应更高温度的能力有关是至关重要的。该项目是现有的和令人兴奋的NERC资助的哥伦比亚项目的一部分，旨在全面了解热环境。安第斯山森林关键气体交换过程和生长的适应。这个博士项目的目的是确定安第斯森林物种的光合作用，呼吸的热适应程度。将测试的关键假设是：-山地热带森林物种的热适应程度将低于温带和高纬度生态系统中观察到的。山区物种的适应潜力将与物种能够生长的温度范围呈正相关，该项目将利用沿着哥伦比亚安第斯山脉海拔梯度建立的三个共同花园实验。具体来说，我们种植了1200棵树（3个地点各400棵，图1-图2），覆盖了哥伦比亚安第斯山脉最主要的山地森林物种的60%。成功的候选人将使用便携式光合作用系统，在三个地点对选定的物种在种植12至18个月后的光合作用和呼吸作用进行叶片水平测量，以量化幼年山地森林物种是否能够适应高温以及在多大程度上适应高温。

Tropical Andean forests host the highest plant biodiversity on Earth. Current rates of warming are three times higher than elsewhere in S. America. Therefore, climate change together with invasive migration by lowland species pose significant challenges to the diversity and functioning of montane forest in the future. Hence, the tropical Andes is a high-priority area in which to study the potential for tropical trees to acclimate their photosynthesis to changes in temperature.There is now evidence for warm-edge range contraction in some high elevation tree species, suggesting a strong response to recent warming. Thus, to substantially advance predictions of how the productivity of tropical Andean forests will change in the future, as well as to assess impacts on biodiversity, it is essential to determine whether changes in species ranges are associated with abilities to physiologically acclimate to higher temperatures.This project is part of an existing and exciting NERC funded project based in Colombia with aim to deliver a comprehensive understanding of thermal acclimation of key gas exchange processes and growth in montane Andean forest.The aim of this PhD project is to determine the degree of thermal acclimation of photosynthesis, respiration of Andean forest species. The key hypotheses that will be tested are: -The extent of thermal acclimation of montane tropical forest species will be less than that observed in temperate and high-latitude ecosystems.-Acclimation potentials of species in montane zones will be positively related to the range of temperatures the species can grow under.The project will use three common garden experiments established along an elevation gradient in the Colombian Andes. Specifically, we are planting 1200 trees (400 at each of 3 sites, Fig1-Fig2) covering 60% of the most dominant montane forest species in the Colombian Andes. The successful candidate will use a portable photosynthesis system to take leaf level measurements of photosynthesis and respiration at the three sites from a selection of species after 12-18 months of planting in order to quantify whether juvenile montane forest species can acclimate to high temperatures and to what extent.