Research
Hot-drought effects on European trees.
I am currently setting up new projects in WSL's Model Ecosystem Facility (MODOEK), where ongoing experimental glasshouses are revealing the effects of heat, drought, and hot-drought on European beech (Fagus sylvatica) and downy oak (Quercus pubescens). Specifically, I am investigating the impacts of the various treatments on leaf temperatures and thermal traits, leaf scorching, photosynthetic thermal tolerance, and photosynthesis.
Acclimation of trees to elevated temperatures in Miami, Florida.
Using the urban heat island effect in Miami, Florida as a 'found experiment' to simulate the effects of climate change, I am exploring the acclimation of seven subtropical tree species to elevated temperatures.
So far, we have found very limited acclimation of thermoregulatory traits and photosynthetic thermal tolerances in our species, but perhaps a greater ability to acclimate in species with broader thermal niche breadths, or those adapted to greater seasonality. Read more about these results in our publication in Tree Physiology!
Despite a lack of acclimation of functional traits associated with leaf temperature, we have not found increases in the thermal optimum of photosynthesis in any of our species, and no significant decreases in maximum photosynthetic rates. Interestingly, photosynthesis in our subtropical species seems to be most strongly controlled by stomatal conductance, similar to previous findings on tropical trees. Read more in our publication in Plant, Cell & Environment!
For a simple overview on urban heat islands and how we can use them to understand biological/ecological impacts of climate change, see our publication in Frontiers for Young Minds!
The effects of rising temperatures to Miami's street trees.
Urban trees provide essential ecosystem services such as shade, heat mitigation, and reduction of air pollution. However, in Miami, air temperatures are already near the upper thermal tolerance for many trees. By 2100, maximum air temperatures are expected to increase by 2 - 4 °C, which will push some trees over the edge.
I am leading a new project with the Jungle Biology lab group to investigate how Miami's street trees will be impacted by climate warming by 2100 and how impacts will differ between native and exotic species.
Preliminary results suggest that climate warming by 2100 will make Miami inhospitable to many of the street trees we currently utilize, including live oak and cabbage palm. Native tree species are expected by to be disproportionately impacted by warming compared to exotic trees. Check out this News At The U article highlighting our poster sharing these results at the Climate and Health Symposium.
Acclimation of trees to elevated temperatures in the Amazon.
As global warming progresses through this century, novel climates are forming in much of the lowland tropics, including the Amazon rainforest. The environmental changes occurring there are unprecedented, making it difficult to predict how forests will continue to respond to change into the future.
To overcome the challenge of studying how Amazonian trees will respond to hotter temperatures, I have been working at a unique site in the Peruvian Amazon, where super-heated water in the Earth's crust emerges to form the Boiling River. The river runs so hot that it heats the air in the forest surrounding the river, creating strong thermal gradients over very short distances (a difference of ~11 C over ~0.5 km).
With the help of this 'natural experiment' for climate change, I tested whether trees of six species acclimate their leaf traits to elevated growth temperatures. Learn more from our recent publication in New Phytologist and commentary by Brad Posch!
Learn more about the Boiling River from my collaborator, Andrés Ruzo.
Taxonomy, distribution, and biology of rare magnolias.
In 2018, I received a Fulbright award to continue a project I had begun in 2017 in collaboration with Lou Jost and the EcoMinga Foundation to expand scientific knowledge on two recently-discovered but poorly known species of Magnolia in the eastern cloud forests of Ecuador.
Starting with only a handful of known individuals each of M. vargasiana and M. llanganatensis, I identified more than 300 more trees belonging not only to these species, but also to a putative natural hybrid of the two (publication forthcoming!).
With increased information on their distributions, population structure, leaf and floral morphologies, and phenologies, we published the first conservation assessments of M. vargasiana (VU) and M. llanganatensis (EN) on the IUCN RedList.
Plant Functional Traits Course 6 - Norway.
As a participant of PFTC6, I was part of an international group of researchers investigating the impacts of various environmental conditions on alpine plants using a trait-based ecology approach along an elevational gradient in Aurland, Norway.
My team explored whether leaf temperatures are associated with air temperatures on diurnal cycles at different elevations, and whether an association (or lack thereof) between leaf and air temperatures leads to shifts in photosynthetic thermal optima within species across different elevations.
My team, led by Dr. Sean Michaletz, is working on a manuscript for publication. The PFTC6 group as a whole will also publish a data paper with all of the plant functional traits, carbon flux data, and remotely-sensed drone imagery generated during the course -- coming soon!
Tree diversity in Sierra Nevada de Santa Marta, Colombia.
Due to its geographic isolation from the Andes and unique elevational gradient, the Sierra Nevada de Santa Marta (SNSM) is recognized for its high rates of endemism, especially in birds, amphibians, and reptiles. Despite the very few studies carried out on plants, high rates of endemism have been found in bryophytes and in the Melastomataceae family. However, rigorous inventories of other plant groups are lacking above 1000 m asl in this ecoregion.
The Jungle Biology Lab spearheaded a project with the Cartagena Botanic Garden and the ProAves Foundation to establish a permanent 1-hectare forest dynamics plot in the SNSM. The plot, established in 2023, gives us detailed data on a tree community in a patch of primary cloud forest around 2200 m asl in the SNSM. The occurrence data is now available on SiB Colombia and GBIF. Read more about our findings from the plot in our recent publication in Annals of Forest Science!
Contamination of Maine lakes by pharmaceuticals and personal care products.
The contamination of surface waters by pharmaceutical and personal care product chemicals (PPCPs) is well-studied in treated wastewater effluent and urban surface waters, but the extent of PPCP contamination in rural areas unaffected by wastewater treatment or industrial runoff is not well understood .
For my undergrad senior thesis, I worked with Dr. Gail Carlson and Dr. Bill G. McDowell to determine whether the rural Belgrade Lakes of Maine are contaminated with pharmaceutical and personal care product chemicals (PPCPs).
We detected a handful of PPCPs, such as caffeine and amphetamine, nearly ubiquitously within and between lakes and across seasons. Although the levels we detected were always very low, they may have significant impacts on the health and behaviors of aquatic biota. Read more about our findings in our publication in the Journal of Environmental Studies and Sciences!