Different flowering times allow these flowers not to compete with each other leading to extinction

An important component of evolution is competition – when resources are limited, plants and animals must compete
for nutrition, mates, and places to live.
This means that the flower-covered meadows of China's Hengduan Mountain are an evolutionary mystery – there are dozens of closely related species and all azaleas live in harmony
.
To find out why, the scientists spent the summer carefully documenting the flowering patterns of 34 species of rhododendron species, and they found a reason why plants were able to coexist: They bloomed at different times of the season, so they didn't have to compete for pollinators
.

"There's a fundamental idea in niche ecology that a species' way of life, such as what it eats and how it adapts, cannot be replicated
in the same community.
If two species with the same lifestyle lived in the same space, they would compete with each other, so one or both of them would adapt to different, non-overlapping lifestyles or they would become extinct," said Rick Ree, director of the Field Museum in Chicago, in the Journal of Ecology.
"Since so many closely related species, rhododendrons, live on these mountains, we wanted to figure out how they coexist
.
"

Rhododendron is a flowering shrub; You may have seen some varieties (such as azaleas) for sale
at horticultural centers.
The Hengduan Mountains, bordering the Tibetan Plateau, are what biologists call a biodiversity hotspot: an ecologically fragile place with an unusually high
number of different species.
Qin Li, a postdoctoral researcher at the Field Museum and the first author of the paper, said: "They form bushes on both sides of the mountain, which look like a sea
of flowers.
"

"The diversity of the rhododendron region is partly caused by speciation, i.
e.
new species diverge from a common ancestor, and newly differentiated species are more ecologically similar and share the same way of life
than those of their distant relatives.
" This means that closely related azaleas in the Hengduan Mountains are more likely to compete with each other for resources
.

When plants compete with each other, they have many ways to adapt so that they can coexist
.
"Their preferences for soil, light, and moisture become very different, which are very basic physiological functional traits
.
" They can also evolve differences to reduce the likelihood of
cross-pollination or competition for pollinators.
This will manifest itself through differences in flower shape, size, or color, or can manifest itself as when their flowers are available to pollinators," Li said
.
"By dividing the timeline, they reduce the chances of
wasting pollen and resources used for reproduction.
"

All of these evolutionary strategies can be used to explain why azaleas did not cause each other's extinction
.
To find out what was going on, Li led a two-month field expedition to Mount Gongga in China
.
After a four-month trip, she chose Mount Gonggar as her study area to conduct a detailed survey of the rhododendron crossing the wider Hengduan Mountains
the year before.

"I've never done fieldwork in southwest China before, but we were actually very close to my hometown in Sichuan, and with my field assistant, co-author Ji Wang from Sichuan University, I spent more than two months and went to more than 100 locations, and we went to each location four times
throughout the season.
" After months of documenting the ecological characteristics of plants, including the size and shape of leaves and flowers, and when plants bloom, Li and her colleagues analyzed the data, using statistical methods to look for trends
.
They determined that a key factor in making these plants coexist was that they all bloomed
at different times.

"In the beginning, we had a hunch that the timing was important, but we weren't very sure, and it's worth noting that in the Himalayas there is a long season where you can see the flowers – some varieties bloom striking against the backdrop of snow, while others wait until late
summer.
Our analysis of the data confirms this suspicion
.
”

The study's findings help illuminate one of
the many ways plants can diversify without causing each other's extinction.
But the timing of the key rhododendron diversity in Gonggar also means that the climate crisis poses an additional threat
to these plants.

"There is plenty of evidence that the speed of climate change is disrupting plant flowering time, leading to species declines and extinctions
.
" "The question is, how will the global plant community respond? Weather is one of the signals that they are blooming, and since climate change affects the weather, this is likely to change the competitive landscape
.
When the environment changes, species have three options: move, adapt, or die
.
Climate change is accelerating this trend
.
”