Research

My research focuses on the ecophysiological responses of plants to climate change. Throughout my career, I have investigated various stressors that compromise plant growth and their chances of survival in tropical and arid systems, and in natural and urban environments.

I consider my work highly interdisciplinary since we have relied on not only leaf and stem-level physiological measurements (gas exchange, stem sap flow, leaf water potential) but have also extensively used weather stations / eddy covariance towers, thermal imaging, canopy imaging (hyperspectral, structure-for-motion, canopy openness), mechanistic and hydrological modeling, among others, to answer our research questions.

Our ultimate research goal is to uncover the underlying mechanisms that enable plants to survive under dire environmental conditions, which then enables the improvement of models and conservation/landscaping practices.

Specific Research Questions

Invasion dynamics in a changing world

Invasive species often have a unique capacity to respond to disturbances. Many theories explaining invasion success have been proposed, including theories like the ‘novel weapons’ hypothesis (i.e., invasive species may output root exudates altering soil to make it uninhabitable for natives) and the ‘competitive release’ hypothesis (i.e., low predation in an introduced range allows the invading species to thrive unchecked). However, a lack of ecophysiological focus in these theories has caused an unclear understanding regarding how invasive plants may acclimate and adapt to changing environments. Our lab explores the physiological mechanisms that may allow invasive species to succeed in the face of global change. We hope to understand how invasion may increase or spread in the future.

Currently working with Russian olive trees (Elaeagnus angustifolia; riparian invasive) and, soon, Tumbleweed (Salsola tragus; prairie invasive).

Cooling capacity of urban tree species

Urban heat island effects are becoming stronger as cities, paved surfaces and populations increase. In addition, heatwaves are projected to be more frequent and longer as climate change intensifies. Tree planting is a common mitigation practice to decrease the heat in urban areas, but the trees' cooling capability beyond shade is not often studied. We currently have plant water use and canopy data for various tree species of Phoenix, AZ, USA to determine how much cooling these trees provide through transpirational and canopy shade cooling across seasons. This is an ongoing project (unpublished), and we have interest in expanding this research into Salt Lake City, UT, USA. We also plan on linking plant tree selection (and physiology) to neighborhood economic statuses to provide better tree choices to provide cooling across neighborhoods.

Alternative water use strategies in hot environments

Understanding plant responses to climate extremes, such as temperature, is crucial for predicting climate change and its effects on the biosphere. Climate change forecasts predict prolonged drier and warmer conditions, with some also subjected to increased frequency and intensity of heatwaves. For many plants, especially those occurring on the warmest edges of a species’ distribution, temperature changes may substantially impact photosynthesis and transpiration, and ultimately larger scale carbon and water budgets. Species or ecosystems may respond differently to climate extremes, in ways that remain poorly known or modeled. We are currently investigating the prevalence of alternative water use strategies (cooling while photosynthesis is thermally suppressed) as a means to survive heatwaves (see Aparecido et al., 2020 ELE). More to come as we progress with our NSF-funded project focused on these strategies. We also intend to expand these projects focused on plant response to heat in different natural ecosystems than the Sonoran desert and at different scales within the plant/ecosystem.

Gas exchange responses to vein damage

Herbivores consume large fractions of plants’ annual primary
productivity. The impacts of herbivory include both the direct loss of carbon and soil nutrient investment in leaf tissue, indirect loss of future carbon gain via lost photosynthesis and/or reduced leaf lifespan, as well as the reduction of transpiration and stomatal conductance for leaf cooling (Duarte et al., 2023 AoBPlants). Thus, quantifying the losses (and gains) of gas and water fluxes from damaged leaves is important for the estimation of the local carbin and water cycle, and thus the resilience of an ecosystem. We are interested in expanding this topic by investigating different herbivory attack intensities (canopy-level). Any interest in leaf venation architecture specific research questions are also very welcome!

Plant-atmosphere responses to wet canopy conditions

Spatial and temporal variation in wet canopy conditions following precipitation events can influence processes such as transpiration and photosynthesis (Aparecido et al., 2016 HYP; Aparecido et al., 2017 TRP), which can be further enhanced as upper canopy leaves dry more rapidly. Furthermore, as wet systems become drier, it becomes more evident the importance of understanding the role leaf wetness plays on alleviating heat and drought on plant canopies. I am particularly interested in expanding my doctoral work on leaf wetness when it comes to foliar water uptake of aridlands and tropical forests (especially shaded, understory plants). I am open to other project ideas that involve leaf wetness (rainfall interception, fog, dew) or other particles/growths that block stomatal regulation (soot, epiphyllic growth, pollution).

Allometric relationships between plant traits and physiological performance

Plants inherently follow an unwritten mathematical growth rule that is usually conserved across plant functional types (e.g., Hagen-Poiseuille law on vascular flow resistance). Most growth patterns follow a nonlinear trend, but these trends can be influenced by changes in composition and structure the ecosystem / forest stand (Aparecido etal., 2021 ActaA) and possibly due to climate change (i.e., specific leaf trait variation, such as leaf size, due to higher vapor-pressure-deficit and heat). Updating these allometric equations as environments change is essential as these equations are valuable tools to determine plant traits without further using destructive sampling.