The traditionally temperate climes of the British Isles are rarely congenial to Cycas revoluta, a species of cycad more at home in the sub-tropical habitats of southern Japan. And yet, this year, two cycad plants (one male and one female) have produced cones in the Ventnor Botanic Garden on the Isle of Wight, UK.
Botanists believe this is the first time the plant has produced male and female cones in 60 million years – and global heating is to blame.
Cycads like these typically live in climates 35 degrees north and 35 degrees south of the equator, and while they can be found on most continents, they are naturally absent from Europe and Antarctica. However, Jurassic-era fossils have been found on both, suggesting they were once far more widespread than they are today. Fossilized cycads from that time show that they did grow in Britain and in areas that include the Isle of Wight coastline.
While this blooming provides today's British botanists with a brand-new horticultural opportunity, it also raises a serious point about human-driven climate change – specifically, the role it played in the "resurrection" of these two plants.
The cycad plant has only successfully produced a male cone out of doors in Britain two times in recorded history. The first, in 2012. The second, earlier this month. This is also the first documented case of a Cycas revoluta developing a female cone, providing the opportunity to transfer pollen and actually generate seeds in the UK for the first time in 60 million years.
The reason for this is that the cycad isn't a particularly hardy crop. It doesn't do well in Britain's chilly winters. But a combination of unusually hot summer heatwaves and a string of milder winters has contributed to the cones' production over the last year – and it could signal the type of flora the country as a whole can expect to grow in the upcoming decades.
"For the first time in 60 million years in the UK we’ve got a male cone and a female cone at the same time," Chris Kidd, the curator of Ventnor Botanic Gardens, told The Guardian.
"It is a strong indicator of climate change being shown, not from empirical evidence from the scientists but by plants."
Cycads dominated the planet's flora from a period 280 million years ago until the first flowering plants appeared some 125 million years ago, a time when the Earth's climate naturally contained higher levels of carbon dioxide. However, the artificially elevated levels of carbon dioxide (generated from greenhouse gas emissions) could be triggering cone production in these British-based plants.
While the Isle of Wight is milder than any part of the UK bar the Isle of Scilly, Kidd told The Guardian this blooming in the Ventnor Botanic Garden could be a predictor for the British landscape in two to three decades' time.