New research suggests that Earth's seasonal cycles can vary greatly over short distances, even at the same latitudes.
Researchers have compiled a detailed map of seasonal rhythms around the world, which shows that in some physically close regions, the timing of seasonal fluctuations, such as the start and end of the growing season, differs dramatically. According to the team, these differences could contribute to high biodiversity in certain ecosystems, the development of new species, and even different types of coffee harvested in Colombia.
“Seasonality can often [be] The idea is that there is a simple rhythm – winter, spring, summer, autumn – but our work shows that nature's calendar is much more complex,” study co-author. Drew Terasaki Hartan ecologist and data analyst from the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia, said in the report. statement. “This is especially true in regions where the shape and timing of the typical local seasonal cycle varies dramatically across the landscape. This could have profound consequences for ecology and evolution in these regions.”
The idea of a simple seasonal growing pattern works well for plants native to high latitudes, such as much of Europe and North America, the researchers wrote in a study published Aug. 27 in the journal. Nature. But in arid or tropical ecosystems, this doesn't work so well.
In their study, Terasaki Hart and his colleagues used 20 years of satellite data that showed how plants reflect infrared light throughout the year to map vegetation growth cycles around the world.
The team found that mountainside areas in tropical regions or mild Mediterranean climates often exhibit seasonal asynchrony, or differences in seasonal cycles over short distances. In these areas, the availability of light and water was more important to the growth cycles of native plants than temperature.
“Our map predicts dramatic geographic differences in flowering times and genetic relatedness among a wide variety of plant and animal species,” Terasaki Hart said in a statement. “It even explains the complex geography of coffee harvesting seasons in Colombia, a country where coffee farms separated by a day's drive through the mountains can have reproductive cycles as out of sync as if they were in opposite hemispheres.”
These very different niches over short distances may explain why tropical regions have such high biodiversity, the team wrote in the study. Species of plants and animals with different seasonal cycles will slowly diverge, reproducing at different times and perhaps forming new species many years later.
The results could help explain how species evolve in other ecosystems, such as river or ocean environments, as well as how environments adapt to climate change, the researchers wrote in the study.
“We suggest exciting future directions for evolutionary biology, climate change ecology and biodiversity research, but this way of looking at the world also has interesting implications for more distant fields, such as agricultural sciences or epidemiology,” added Terasaki Hart.
