For most living things on the planet, seasons are kind of a big deal. They've marked the way Earth’s many inhabitants have lived their lives for millennia. Up until recently, scientists have taken it as a given that seasons = consistent, universal and home to distinct growing periods that we all benefit from.
But, after scientists have had a (lengthy) squiz at Earth from space, it turns out it isn’t as simple as it seems — and South Australia is in the hot seat.
A new study released by Nature Journal has revealed that there are certain parts of the world where seasons dramatically differ between locations that are just several kilometres apart, generating major ecological consequences for humans, animals and plants alike. This is called 'seasonal asynchrony'.
After studying 20 years' worth of satellite footage, scientists have successfully tracked two decades' worth of seasonal progression across the globe – a thing that's known to the science world as 'phenology', and to most humans, the simple turning of seasons. After gazing down at the Earth from space, the researchers discovered there are certain 'hot spots' spread across the world where seasons are out of sync in a fairly dramatic way.
They found that this is the case across five of Earth’s Mediterranean climate regions, one of which is found in Australia. Although the name conjures up visions of Greek wine and pasta, the Mediterranean moniker is for climates where winters are wet and mild and summers are dry and hot.
This is a familiar situation for southern Australian dwellers, but it turns out we share this in common with our distant sisters in California, Chile, South Africa and (duh) the Mediterranean. And, scientists say, it’s no surprise that all of these “hot spots” where seasons are out of sync are home to some extraordinary biodiversity and animal species.
What does this mean for southern Australia? All the people and ecosystems in this region share what's called a “double peak seasonal pattern”, meaning that forests and plants here grow to their peak two months later than their neighbours.
This is interesting because it means particular places in southern and south-western Australia have starkly different rainfall patterns, resulting in staggered growth of animal and plant species. As a result, plants in these regions have likely morphed into new species over time, which in turn influences the evolution of the animals that feed off them, resulting in a rich tapestry of biodiversity. Hello, Kangaroo Island.
Why is this important? Understanding how the seasons work is vital to people in southern Australia and other Mediterranean climate regions. Out-of-sync seasons can lead to out-of-sync resource distribution, resulting in unbalanced reproductive cycles for animals living there and reduced interbreeding. This results in potential biodiversity loss, while also giving us new perspectives on the effects of climate change for these unique ecosystems. As all things are interconnected, out-of-sync seasons could also deeply affect humans who eat, breathe and generate agriculture in these areas.
Basically, out-of-whack seasons in certain areas do, in fact, affect us all. Want to see it for yourself? You can virtually explore 20 years of seasonal progression with Nature's interactive map.