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Climate crisis will cause a sharp drop in flower abundance, which will make pollinators look for food elsewhere.

Climate crisis will cause a sharp drop in flower abundance, which will make pollinators look for food elsewhere.

Sharp drop in flower abundance caused by climate crisis will leave pollinators searching further for food

Sharp drop in flower abundance caused by climate crisis will leave pollinators searching further for food
Artificial heaters hanging above the experimental plots, raising local temperature by 1.5 ºC to simulate global warming. Credit: Ellen D Moss

It is predicted that global average temperatures will have risen by between 0.9 and 2.0 ºC around the middle of this century, according to the IPCC’s intermediate emission scenario RCP4.5. Many species, particularly those with very specific needs for food, habitat and reproduction, will not be able adapt.

Because 35% of our crops are dependent on pollination from insects, it is important to study the impact of global warming on the fitness and health of wildflowers and insects. . We may be able mitigate the changes once we have a better understanding of them. Wild and wild .

This is the first time that scientists from Newcastle University, UK have shown experimentally the immediate impacts of simulated climate changes on wildflower reproduction success and the food web. and pollinators. The results of the pollinator surveys are published in Frontiers in Plant Science.

Lead author Dr. Ellen D Moss, a postdoctoral scientist in the School of Natural and Environmental Sciences at Newcastle University, said: “Here we show that a 1.5°C increase in temperature can drastically reduce food resources for pollinating insects, cause pollinators to visit a wider range of plants for food, and reduce For some wildflowers, and for others to increase it.”

Simulating global heating in the wild

The authors simulated global warming on outdoor experimental plots at an agricultural research station in the UK, by raising the ambient temperature by a constant 1.5 ºC with infrared heaters. They then compared plant and bug biodiversity and visited patterns on the flowers between these and unheated control areas in 2014 and 2015.

Because climate change in northern Europe is also predicted as leading to an increase in rainfall they further studied the effect of irrigating plots (supplying 40% of the local monthly precipitation on top of natural rainfall) separately or in combination with heating.

The plots were plowed over the years and then sown in spring with wheat and eight native, annual, insect–pollinated herbs that are typical of wheat fields like corn marigold and cornflower. The plots were not treated with pesticides, which allowed wildflowers to flourish and colonize them.

The authors counted the number and types of plants in each plot, as well as the number of flowers, during the flowering seasons from June through August. They also weighed the dried-out ripe seeds of each species and measured the amount of nectar per bloom. They counted the number, in 20-minute intervals, of each species of insect visiting each plant species. Then, they collected the insects to identify the species.

The authors recorded a total of 25 species and 80 insect species in 2014, as well 19 species and 69 insect species in 2015. The number of plant or insect species did not depend on the treatment, indicating that heating by 1.5 ºC, with or without extra water, does not lead to immediate changes in species diversity. The immediate effects were subtler. The plots were heated and most plant species became ‘losers’ in terms of reproductive potential: they produced fewer seeds or grew fewer flowers.

“Our experiment showed that under an increase of 1.5°C there was almost a 40% reduction in the number of floral units throughout the season, which represents a significant decrease in available food for flower visitors,” the authors wrote.

The lone winner

The wildflower common field speedwell was the only winner in reproductive terms in simulated climate change. It produced more and heavier seeds in heated areas. However, the species’ flowers produced 65% less nectar when heated, making it less appealing to pollinators.

The researchers also observed subtle changes in the food Web that were immediate. The food web was more complex in heated plots because insects species visited more of them. The number of flowers visited per visit was also increased. The reduction in food supply likely caused this change in insect foraging behavior. The number of species recorded was not affected by heating and extra water. However, the compositions of both plant and insect communities were significantly different between the treatments.

Moss stated that “our results demonstrate that climate change could have severe consequences on some species of wildflowers, and their pollinators within agricultural systems, and that their community composition will likely change in the future.”

Dr. Darren Evans from Newcastle University, professor of ecology, conservation, and ecology, was co-author. He said, “Our results provide valuable insight as to how climate warming affects noncrop plants, as well as how species commonly regarded as weeds underpin essential insect pollinator communities.”

See Also
Jonathan Overpeck

“Going forward, having better understanding of how climate change affects the direct or indirect actions of a larger network of Interactions will make it easier to adapt our farming systems to a changing world.

Sow pollinator habitat seedlings that grow where they’re planted

More information:
Experimental climate warming reduces flower resources and alters insect visitation in a cereal system. Frontiers in Plant Science (2022). DOI: 10.3389/fpls.2022.826205 , … pls.2022.826205/full

Climate crisis will cause a sharp drop in flower abundance, which will lead to pollinators looking for food (2022, 23 February)
Retrieved 23 February 2022

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