Tropical Dry Forests: Remote sensing and ecological fingerprints of ecosystem succession

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。与热带雨林相比，这个生态系统中的植物物种的特点是生长速度较慢，繁殖周期有限，结构和生理多样性更多。TDF是世界各地社区生态系统服务的重要蓄水池。仅在美洲，估计就有近6000万人受益于他们提供的服务(如水生产、授粉)。尽管它们很重要，但人们对这些生态、生物物理/水文过程及其与这些生态系统服务的联系知之甚少。 拟议研究计划的目标是填补与TDF如何应对气候变化以及相应地在其生态系统服务中产生的变化相关的关键知识空白。本研究计划的短期目标集中在三个具体的研究领域：(1)藤本植物和树木在长波热红外中的光谱反射率表征：我建议将我们过去在叶水平上的工作扩展到长波热红外(TIR：7.5~12.5µm)，以探索藤本植物和树木在TIR中的差异和控制反射率的机制；(2)量化TDF对气候变化的响应：我工作的这一部分将旨在利用CO2/H2O通量和光合作用有效辐射(FPAR)等关键变量来确定TDF是否接近影响其二氧化碳吸收以及其物候响应的高温阈值；(3)量化藤本植物对TDF结构的影响：随着藤本植物在热带环境中变得更加主导，我建议使用地面LiDAR衍生技术来研究它们对不同生态演替水平的TDF结构的影响。从长远来看：我的研究计划将有助于在遥感和次生再生不同阶段的生态过程之间的联系方面的科学知识。 我期望我的工作成果将有助于政策制定者制定成本效益高、注重结果的方法，以保存整个美洲的TDF。

Seasonally dry tropical forests (TDFs) account for 42% of all tropical forests and contain a wealth of unique biodiversity. Plant species in this ecosystem are characterized by slower growth rates, restricted reproductive episodes, and more structural and physiological diversity than found in tropical rainforests. TDFs are important reservoirs of ecosystem services for communities around the world. In the Americas, alone, it is estimated that nearly 60 million people benefit from the services that they provide (e.g. water production, pollination). Despite of their importance, little is known about these ecological, biophysical/hydrological processes and their linkages to these ecosystems’ services. The objective of the proposed research program aims to fill key knowledge gaps related to how TDFs may respond to climate change and, in turn, the consequent shifts produced in their ecosystem services. Short-term goals of my research program focus on three specific research areas: (1) Characterization of the spectral reflectance of lianas and trees in the long-wave thermal infrared: I propose to expand our past work at the leaf level into the long-wave thermal infrared (TIR: 7.5µm to 12.5µm) to explore differences between lianas and trees and the mechanisms that control the reflectance in TIR; (2) Quantifying TDF response to climate change: This component of my work will aim to determine if TDFs are nearing high temperature thresholds that would affect their CO2 uptake as well as their phenological response using key variables such as CO2/H2O fluxes and the Fraction of Photosynthetically Active Radiation (FPAR); (3) Quantifying the impact of lianas on TDFs’ structure: As lianas become more dominant in tropical environments, I propose to examine — using ground LiDAR derived technologies — the impact that they have on TDFs’ structure across different levels of ecological succession. Over the long-term: My research program will contribute to scientific knowledge in the nexus between remote sensing and ecological processes across different stages of secondary regeneration. I expect that the outcome of my work will assist policy makers in developing cost-effective, results-oriented methods for preserving TDFs across the Americas.