Lin Meng
Lin Meng

In today's Plant Phenomics First Author Insights, we invited Lin Meng to share her insights as the first author of Urban warming advances spring phenology but reduces the response of phenology to temperature in the conterminous United Statespublished in PNAS.

Tell us about yourself a little bit, what's your current position, your education experience and how did you get into science.

I am a Ph.D. candidate at the Department of Geological & Atmospheric Sciences, Iowa State University studying Environmental Science. I received my B.S. degree in applied meteorology in Shenyang Agricultural University, China in 2013 and M.S. degree in meteorology in Chinese Academy of Meteorological Sciences, China in 2016. I was also a visiting student at Potsdam-German Research Centre for Geosciences in Germany during 2016 – 2017.
My research focuses on understanding the changes in plant phenology under urbanization and climate change. In addition, I was a research intern at Oak Ridge National Laboratory during three summers from 2017 to 2019 working on phenology modeling.
My interest in phenology and global environmental change arose from personal experience when I saw cherry blossoms in Beijing in 2015. The forecast indicated peak blossom time was half a month early in downtown Beijing compared to rural areas. The night before I visited a park to see "advanced stage blossoms", the snow came unexpectedly and what I saw the next day was an almost complete loss of those emerging blossoms. Later I learned that warming environments with great fluctuation advanced the growing season of trees and place them at risk (e.g., urban heat island), which inspired me to think: how do trees know when to leaf out and what affects this timing? This is the reason why I have been committed to conducting research on phenology. I serve as the student representative in the committee of the Global Environmental Change Section of the American Geophysical Union (AGU). I am also the current liaison between the Student Section and Human Ecology Section of the Ecological Society of America (ESA).
I love photography and traveling. I run half marathon. I also enjoy the outdoors such as hiking and kayaking.

What was the significant issue(s) in your paper? Why did you and your team care about it?

Plant phenology, the timing of recurring events in plants’ life cycles, is a sensitive and robust biological indicator of climate change. For example, we have a very early bloom in 2020 in the U.S. happening now because of the relative warm and early spring this year. Plant phenology also affects many feedbacks of vegetation to the climate system, such as by influencing the seasonality of albedo, surface roughness length, and fluxes of water, energy, CO2. We want to understand how and to what extend plant phenology changes under future climate warming.

What was the problem(s) to be solved and your proposed solution?

Although it is widely acknowledged that warmer temperature advances spring phenology in the Northern Hemisphere, how and to what extent the warming temperature affects plant phenology are still uncertain. In addition, previous studies shed little light on future phenological changes when temperatures are projected go beyond the range of historical or present-day variability. Our overarching goal is to understand the phenological changes under future warming and we achieve it by asking three questions: (1) how has phenology and the covariation between phenology and temperature changed in cities? (2) Were these changes associated with background climate or local modified environment? (3) what physiological mechanisms drove these changes?
We employ a novel space-time-substitution approach to examine the phenological changes under climate warming. Because air temperatures in cities tend to be warmer than in their rural surroundings, a phenomenon known as the “heat island effect,” cities can be used as natural laboratories for studying the ecological effects of climate warming. The comparison between the urban and rural phenology offers a distinctive analog for possible phenological changes under projected warming and facilitates relevant investigation of underlying mechanisms. We examined phenological changes in urban versus rural areas in 85 large cities in the U.S. using satellite data and investigated the possible mechanisms.

What was the contribution(s) of this study and who could benefit from it?

The results shed lights on the future phenological changes and its trend as warming continues, that is, the onset of spring phenology will likely advance but will slow down as the general trend toward warming continues. Moreover, this new understanding could help modelers to refine the Earth system models and improve prediction accuracy.

Reference

Meng, Lin, et al. "Urban warming advances spring phenology but reduces the response of phenology to temperature in the conterminous United States." Proceedings of the National Academy of Sciences 117.8 (2020): 4228-4233. DOI:  https://doi.org/10.1073/pnas.1911117117