Research

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 - pictured).

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 This is an ongoing project (unpublished), and we are currently collecting similar preliminary data in Salt Lake City, UT, USA. Our ultimate goal is to link plant tree selection (and physiology) to neighborhood economic statuses to provide better tree choices to provide cooling across neighborhoods.

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 are currently expanding our work on plant responses to heat to different natural ecosystems other than the Sonoran desert and at different scales within the plant/ecosystem, such as Red Butte Canyon in UT.

As environmental change pushes native plants to their functional limit, researchers have wondered whether mixing resistant to less resistant native genes might confer an ecological advantage to these hybrid species; and possibly be used as a restoration option for natural systems or used as a drought or heat tolerant alternative for urban environments. Our lab is taking advantage of a 50 yo established Quercus common garden located at the University of Utah and managed by the Red Butte Garden to investigate these presumed advantages of hybrid species, in this case within the oak clade, with special emphasis on Q. gambelli and Q. turbinella that have naturally occurring hybrids along the back Rocky Mountain range. Natural populations are currently being explored in collaboration with the Red Butte Garden and we plan on expanding this project beyond the common garden setting in the upcoming years.

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!

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).

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.