Grizzly bears, bisons, and the ways to find them, appeared to be the highlights of Wednesday evening’s “Meet your Prof!” event organized by the Student Association for Geography and Environment. Hosting Dr. Yuhong He, associate professor in the Department of Geography at the University of Toronto Mississauga, the event saw discussions about He’s research with endangered species, remote sensing, and her experiences through charting a career in geography.
“I got my bachelor and master’s in China in meteorology, and then I worked at the National Weather Centre for 2 years,” says He. At the weather centre, the associate professor worked with supercomputers and wrote programming for predicting weathers. As she describes, they produced predictions every afternoon at five o’clock because that is the time when people were sent a phone message about 1-day and 3-day weather forecast. Weather predictions, according to He, involve monitoring different conditions at multiple scales. The geography professor explains, “[We would] make initial predictions at eight o’clock in the morning, with real-time weather data throughout the day to correct and update the predictions.”
In early 2000s, He explains she used the percentage likelihood of rainfall and temperature the next day to let people know how they should dress up. He also mentions her job was to ensure that the codes she wrote could produce reliable results. He would then use the supercomputer to run the models and send those predictions out to servers, adding that “there can always be hiccups however, because weather is variable.”
He explains, “No matter how many combinations of parameters you consider, your model might not have ever seen a new combination of weather conditions come in, leading to an unexpected model output.” In spite of these disruptions however, the associate professor says, “I was often called at 5 o’clock to fix the model and I would have to run back to the office.”
He also laughs as she says that the average life expectancy for chief scientists at weather centres used to be 60 years, “Because of the pressure, it’s very hard to predict the weather. People complain about the accuracy, without recognizing how difficult it is,” says He, and explains that when there is a big system coming in, for example, you have to make predictions on when it gets to Mississauga, and when it comes to Oakville? At what intensity? and it can depend on many variables, including terrain. Predicting these variables together and integrating them, according to He, is based on very complex physics.
After two years at the centre, He commented on why she decided to move on from the centre “One, it was too stressful, and second, it wasn’t exactly what I wanted to do. It is a good service, but I wanted to do something else.” He mentions she then moved on to University of Saskatchewan to do her Ph.D. with Dr. Xulin Guo, and “I began to work on completely new things, remote sensing.”
Remote sensing involves processing images taken from different devices such as satellites, airplanes, drones, and mobiles, and, as He describes, “It pretty much allows you to study anything on earth that you are interested in. I studied grasslands in Saskatchewan using remote sensing.” She says that one of the projects I worked on was for bison because it actually disappeared for a long while due to hunting.
Following the reintroduction of the bison to Grasslands National Park as a native species in the winter of 2005, He says, “[Scientists] wanted to ask, is this actually okay? How many should the park introduce? And is this okay for the other native species present there? There are a lot of endangered species in those protected areas, both animals and plants.” She describes her experience during her Ph.D. project: “As a remote sensing student I was asked to work with a research scientist from Parks Canada.” He discusses how without remote sensing, it can be very difficult to spatially picture the park. “Even though people think it’s just a park, it is huge, and remote sensing can tell you where what is, and also how much,” says He.
Remote sensing can also be used to study conditions in a habitat, how those conditions have changed over time based on a spatial and temporal analysis, and as He elaborates, “With data dating back to the 70s, we can see how every year and every month conditions are changing and what is emerging or disappearing. I was involved in a project that used the time series images and spatiotemporal analysis to predict changes in bison populations and how much they would reproduce, and then predict what would happen to this grassland habitat in 50 and 100 years with 71 animals introduced.”
The geography researcher then shares, “In 100 years, we found the grassland would probably disappear.” She elaborates by saying, “The reason is that there will be too many babies, and without any control or hunting, the population would just grow. Although first scientists thought the park was large enough to accommodate.” She adds, “After two years they realized they really have to control this, because population numbers had already increased greatly by then.”
After completing her work on grasslands, He says she “joined Dr. Steven Franklin’s team to work on a grizzly bear project which was also very exciting.” He discussed that grizzly bear GPS points were collected and the goal was to study how oil exploration is disrupting the landscape by segmentation and how this disruption impacts native species.
With expansive oil exploration installments, He says, “There are almost no intact natural forests in that area other than the Wood Buffalo National Park—everywhere else it’s more or less disturbed.” For her project, the researcher says, “[I] wanted to track the disturbances and relate that to the grizzly bear population conditions. My role was largely to use remote sensing to extract information. Because for such a large geographical area, you cannot survey the land to track disturbances and impacts without remote sensing.”
He says she used remote sensing to map disturbances and developed methods to study impacts of clear cutting, and some researchers did find that male and female grizzly bears respond to those disturbances differently: “Interestingly, researchers found that males like to go to the clear-cut forest areas because of the high berry growth there, and they use that as a food source. Females don’t like to hang around disturbed areas, especially moms, because of the associated risk.”
After a short postdoctoral study, He describes how she moved on to U of T, “Luckily, I was interviewed by UTM geography about eight months after I graduated from my Ph.D. and after I was offered, I moved to Toronto with my family, and I started teaching and taking care of graduate students in my lab.”
He’s laboratory uses remote sensing techniques, spatial analysis, climate data, and ecosystem modelling in studies of natural or managed systems, the latter being grassland, forest, wetland, and agriculture. The team attempts to understand the linkages between observed environmental changes and anthropogenic driving factors, such as oil and gas exploration, at multiple spatial and temporal scales.