The key findings of the study challenge the existence of a universal model of four seasons. The map created during the work demonstrated that even neighboring regions can have significantly different timings for important seasonal events, including the start and end of the growing season. For example, in mountainous areas in the tropics or Mediterranean zones, seasonality often shows asynchrony over short distances.
Main conclusions: absence of universal seasons
In high latitudes, such as most of Europe and North America, temperature remains the main factor influencing vegetation growth. At the same time, in tropical or arid ecosystems, local availability of light and water is much more important than average temperature indicators.
These differences in seasonal niches may contribute to high levels of biodiversity, especially in the tropics. The separation of reproductive cycles over time leads to the formation of new species. Practically, this study explains, for example, the complex structure of coffee harvesting seasons in Colombia, where farm plots separated by just a few hours' travel through the mountains may have non-overlapping reproductive cycles, as if they were in opposite hemispheres.
Scientists' opinion
“Seasonality is often perceived as a clear rhythm — winter, spring, summer, autumn — however, our work demonstrates that the natural calendar is much more complex,” says Drew Terasaki Hart. She emphasizes that this is particularly noticeable in regions where the shape and timing of local seasons vary greatly depending on the landscape. “This can significantly impact ecological and evolutionary processes in these areas.”
The study is not the only one of its kind. It resonates with the work of other specialists who emphasize that human impact and climate change not only shift seasons but also create new phenomena, such as the “haze season” in Southeast Asia or the “garbage season” in Bali. Additionally, it aligns with the fact that many cultures have used more detailed calendar systems, dividing the year into 24 seasons or 72 micro-times for a more accurate description of natural changes.
Thus, the research team from CSIRO provides a new tool for understanding life on our planet. This map of seasonal rhythms opens new horizons for both fundamental science in the fields of evolutionary biology and climate change ecology, as well as for applied disciplines such as agriculture, forestry, and epidemiology. It reminds us that nature operates not according to a simplified model, but according to a complex and variable score that we are just beginning to understand.
