Lianas and ecosystem structure of secondary tropical dry forests

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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 Niño- 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.