Lianas and ecosystem structure of secondary tropical dry forests

季节性干燥的热带森林占所有热带森林的42%，蕴含着丰富的独特生物多样性。与热带雨林中的植物物种相比，该生态系统中的植物物种具有较慢的生长速度、有限的生殖周期以及更多的结构和生理多样性。仅在美洲，估计就有近6000万人受益于TDF提供的生态系统服务(例如，水生产、授粉)。尽管它们很重要，但人们对它们对气候变化的生态反应以及这种反应如何反映在它们的生态演替过程中(幼林与老林)知之甚少。 拟议研究计划的目标是填补发展中国家如何应对气候变化及其生态系统服务转变方面的关键知识空白。在短期内，我的研究将集中在两个主要主题上：(1)确定热带森林在气候变化下的恢复机制，特别是在藤本植物侵扰对其功能所起作用的背景下；(2)利用厄尔尼诺-南方涛动(ENSO)等现象作为潜在气候变化情景的替代，增进我们对热带森林如何应对极端气候事件的理解。从长远来看，我的研究计划旨在填补知识空白，整合遥感、碳通量测量、生态系统结构和TDF再生不同阶段的生态过程。这些信息将帮助政策制定者制定具有成本效益和注重结果的方法，在整个美洲保护这一脆弱的生态系统。 我的研究计划的短期目标将涉及科学发现的四个核心领域。这些核心领域旨在加强对以下内容的理解：(1)无藤本植物和藤本植物出没地区基本气候变量(ECV)的时空变异性；(2)藤本植物引起的TDF的三维(结构)变化；(3)藤本植物负载引起的树木代谢条件的变化；以及(4)利用涡旋协方差方法对TDF对极端气候事件的响应。这些问题将在不同的空间范围内进行研究，范围从个别地块到区域尺度。 TDF是世界上受保护和研究最少的生态系统之一。将地块和景观尺度的研究成果结合起来，将进一步发展监测土地复盖变化的更好机制，并将这些观测与保护方法联系起来。此外，通过重点研究藤本植物等非结构性系统对TDF的影响，将更好地了解该生态系统对未来气候变化条件的反应。

Seasonally dry tropical forests (TDFs) account for 42% of all tropical forests and contain a wealth of unique biodiversity. Plant species in this ecosystem have slower growth rates, restricted reproductive episodes, and more structural and physiological diversity than those found in tropical rainforests. In the Americas alone, it is estimated that nearly 60 million people benefit from the ecosystem services (e.g., water production, pollination) that TDFs provide. Despite their importance, little is known about their ecological response to climate change and how this response is reflected in their ecological succession processes (young vs. old forests). The objective of the proposed research program is to fill critical knowledge gaps in how TDFs respond to climate change and the consequent shifts in their ecosystem services. In the short-term, my research will focus on two main topics: (1) Determining the resilience mechanisms of tropical forests under climate change, especially in the context of the role that liana infestation plays on their functioning; and (2) Advancing our understanding of how TDFs respond to extreme climatic events using phenomena such as El Nio- Southern Oscillation (ENSO) as proxy for potential climate change scenarios. In the long-term, my research program aims to fill knowledge gaps integrating remote sensing, carbon flux measurements, ecosystem structure, and ecological processes at different stages of TDF regeneration. This information will assist policymakers in developing cost-effective and results-oriented methods for preserving this fragile ecosystem across the Americas. The short-term goals of my research program will involve four core areas of scientific discovery. These core areas aim to enhance the current understanding of: (1) the spatiotemporal variability of Essential Climatic Variables (ECVs) in liana-free and liana-infested regions; (2) the three-dimensional (structural) changes in TDFs induced by lianas; (3) the changes that liana loads induce in the metabolic conditions of the trees; and (4) the response of TDFs to extreme climatic events using eddy-covariance approaches. These questions will be studied at different spatial extents ranging from the individual plot to a regional scale. TDFs are among the least protected and studied ecosystems worldwide. Integrating research results from plot and landscape scales will further development of better mechanisms to monitor land cover changes and link those observations to conservation approaches. Also, by focusing on the impact that non-structural systems such as lianas have on TDFs, a better understanding will be gained of the response of this ecosystem to future climate change conditions.