Researchers from Ghent University have been able to map the effects of climate change thanks to images of the Tour of Flanders. By studying 36 years of footage of the popular cycling race, the researchers have discovered that trees along the route have started blooming earlier in the last few decades, indicating rapid climate change at work in the region.
Picture from WikiCommons: Koppenberg hill during the 2009 Ronde van Vlaanderen (Tour of Flanders) Classics road cycling race.
Belgian bike race footage is the latest data to be added to the mounting evidence of rising European temperatures over the past century. The trees along the annual Tour of Flanders route are showing increased amounts of leaves and flowers each year, in footage archived by Belgian national TV. The race images were analyzed by thesis student Lisa Van Langenhove and her supervisors at Ghent University this spring. The research group compared the foliage of trees on twelve slopes of the route between 1980 and 2016.
Initiated in 1913, The Tour of Flanders has been taking place every spring for over a century, with a similar date and route each year. The consistency of the race has inadvertently led to an excellent chronological record of Flemish greenery, perfect for scientific analysis.
According to Professor Pieter De Frenne, earlier images of the race showed leafless trees that had yet to bud. After 1990, the trend shifted: several tree species already sported green foliage by the time of the race. "This has happened because temperatures have risen sharply in recent years. On the Tour of Flanders, temperatures have risen about 1.5 °C since 1980." says De Frenne.
We know that climate change makes nature grow faster in the springtime. However, the degree to which plants and animals react to this change differs greatly from species to species.
The team not only saw increased foliage on trees such as hawthorn, hornbeam and birch, but also saw a shift in flowering species, with an early bloom evident on magnolias. "These shrubs and trees never used to show leaves or blossoms on the day of the Tour of Flanders. In recent years this trend has changed, mainly due to the warming of the climate." says De Frenne.
Though one might think early greenery is a nice sign of spring, this premature budding is not a good thing for the ecosystem as a whole. As trees crow a full crown of leaves earlier in the year, the amount of shade cast on lower vegetation increases drastically. This leads to significant problems for both flora and fauna: stunted by early shade, wildflowers tend not to bud, decreasing the amount of nectar available to insects such as bees and butterflies, which in turn affects birds and even mammalian species. Slow to adapt to a rapidly changing climate, fragile ecosystems can easily be thrown off-kilter. De Frenne continues: "For some species, this early sunshine is good news. For example: some trees grow more leaves and produce more wood. However, for animals and plants that grow underneath those trees, this warmth is not beneficial," says De Frenne.
Video recordings of cycling races are an enormously valuable resource; cycling races such as the Tour of Flanders follow a near-identical route every year and thus allow us to closely monitor plants in the region over time.
The data cycle
According to the researchers behind this study, the use of archived images presents an excellent method for estimating the effects of climate change. Using footage from popular public events allows for excellent replicability that can be easily combined with other types of data such as temperature records. "Video recordings of cycling races are an enormously valuable resource; cycling races such as the Tour of Flanders follow a near-identical route every year and thus allow us to closely monitor plants in the region over time."
This has happened because temperatures have risen sharply in recent years. On the Tour of Flanders, temperatures have risen about 1.5 °C since 1980.
Cycling competitions have a number of additional advantages over other types of sporting footage: they are one of the few popular events that take place on public roads in the spring, and most have been running for decades.
“We know that climate change makes nature grow faster in the springtime. However, the degree to which plants and animals react to this change differs greatly from species to species. Some react very strongly; others, not at all. Until recently, our knowledge of the effect of climate change on deciduous trees was mainly based on observational studies: data collected in a small number of forests, parks and gardens, and in a limited number of species such as oak, beech and hazel. This new method makes it possible to investigate a large range of, often understudied, plant species. The only requirement for this type of research is continual television broadcasting of this ongoing annual bike race."