Lab

UBC Physiological Ecology Lab

About the lab

We are interested in the physical processes linking environmental variation to plant physiology, and how this “scales up” to influence higher-level patterns and processes. Our research is interdisciplinary and draws on various fields including ecology, plant physiology, engineering, and geoscience.

Featured projects (3)

Project
This project uses a process approach to link fire behavior to plant physiology and fire effects to higher levels of ecological organization.
Project
This project develops and evaluated novel mechanistic theory for linking variation in climate and leaf traits to variation in leaf temperatures and physiological rates.
Project
This project aims to develop and test novel process-based theory for understanding variation in terrestrial ecosystem processes across the globe.

Featured research (2)

Portable gas exchange analyzers provide critical data for understanding plant‐atmosphere carbon and water fluxes, and for parameterizing Earth system models that forecast climate change effects and feedbacks. We characterized temperature measurement errors in the LI‐COR LI‐6400XT and LI‐6800, and estimated downstream errors in derived quantities, including stomatal conductance (gsw) and leaf intercellular CO2 concentration (Ci). The LI‐6400XT exhibited air temperature errors (differences between reported air temperature and air temperature measured near the leaf) up to 7.2 °C, leaf temperature errors up to 5.3 °C, and relative errors in gsw and Ci which increased as temperatures departed from ambient. This caused errors in leaf‐to‐air temperature relationships, assimilation‐temperature curves, and CO2 response curves. Temperature‐dependencies of maximum Rubisco carboxylation rate (Vcmax) and maximum RuBP regeneration rate (Jmax) showed errors of 12% and 35%, respectively. These errors are likely to be idiosyncratic and may differ among machines and environmental conditions. The LI‐6800 exhibited much smaller errors. Earth system model predictions may be erroneous, since much of their parametrization data was measured on the LI‐6400XT, depending on the methods used. We make recommendations for minimizing errors and correcting data in the LI‐6400XT. We also recommend transitioning to the LI‐6800 for future data collection.
● The plume of hot gases rising above a wildfire can heat and kill the buds in tree crowns. This can reduce leaf area and rates of photosynthesis, growth, and reproduction, and may ultimately lead to mortality. These effects vary seasonally, but the mechanisms governing this seasonality are not well understood. ● A trait‐based physical model combining buoyant plume and energy budget theories shows the seasonality of bud necrosis height may originate from temporal variation in climate, fire behaviour, and/or bud functional traits. To assess the relative importance of these drivers, we parameterized the model with time series data for air temperature, fireline intensity, and bud traits from Pinus contorta, Picea glauca, and Populus tremuloides. ● Air temperature, fireline intensity, and bud traits all varied significantly through time, causing significant seasonal variation in predicted necrosis height. Bud traits and fireline intensity explained almost all the variation in necrosis height, with air temperature explaining relatively minor amounts of variation. ● The seasonality of fire effects on tree crowns appears to originate from seasonal variation in functional traits and fire behaviour. Our approach and results provide needed insight into the physical mechanisms linking environmental variation to plant performance via functional traits.

Lab head

Sean Michaletz
Department
  • Department of Botany

Members (6)

Raquel Partelli Feltrin
  • University of British Columbia - Vancouver
Josef Garen
  • University of British Columbia - Vancouver
Nicole N. Bison
  • University of British Columbia - Vancouver
Milos Simovic
  • Cleveland State University
Marcella Cross
  • Cornell University
Yi He
  • Zhejiang A&F University

Alumni (5)

Hugo Galvão Candido
  • Universidade Federal de Viçosa (UFV)
Isaac Borrego
  • US Forest Service
Elizabeth J Kleynhans
  • University of British Columbia - Vancouver