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- An experimental study of unprecedented significance has shown that climate change affects wildflower abundance and results in less nectar and lighter seeds.
- These changes also affect pollinating insects that visit the flowers: they must visit more flowers and more often to collect the food.
- A decrease in flowers means that plants are less likely to reproduce and there are fewer food resources available for invertebrates who rely on them for food, shelter, and habitat.
- Researchers say that climate change may alter the composition of wildflowers and their pollinators, thereby affecting agricultural crop yields.
Think of climate change, and you’ll probably picture devastating floods, raging wildfires, or parched earth. Coral bleaching and mass displacements may also be included for those who are environmentally conscious. The vibrant wildflowers of nearby meadows are not likely to be considered victims of climate changes. Recent research suggests that the future of these beautiful blooms could be grim in the face a warming planet. StudyPublished in the journal Frontiers in Plant Science.
This first-of-its-kind study, conducted in the U.K., found that wildflowers across Northern Europe would likely see a steep decline in abundance — up to 40%. The researchers created a simulation of the warmer and wetter climates predicted for the region by climate change. In this new scenario, some plants produced flowers that had 60% less nectar and more or fewer seeds. These changes meant that pollinating insects had more to visit flowers in order to collect the nectar and pollen, and they visited each flower more often.
“Our results demonstrate that climate warming could have severe consequences for some species of wildflowers and their pollinators in agricultural systems, and shows that their community composition is likely to change in the future,” said lead author Ellen D. MossResearch associate at Newcastle University, U.K.
While theoretical studies have predicted that climate change could accelerate pollinator losses and wildflower declines, Moss’s study marks the first time scientists have put the theory to the test in an experimental setting. Previous climate change studies focused on a few plants or pollinating bugs in a particular area, but not the whole community.
“This study adds to the weight of evidence that pollinators are at risk from multiple stressors,” said ecologist Jane StoutTrinity College Dublin, which was not part of the study. “They are losing places to feed and breed, and they are stressed by pesticides, disease and changes in climate.”
The researchers planted spring wheat and some native wildflowers on small plots of land in North Yorkshire. They then heated some of these plots with infrared heaters to increase the soil temperature by 1.5° Celsius (2.7° Fahrenheit) and they increased the water supply by 40% to mimic the predicted wetter conditions from future climate change for Northern Europe. To compare their results, they used the non-heated plots as a control.
The researchers kept track of the two flowering seasons 2014 and 2015. They also tracked the different species of plants that grew in these plots, their number of flowers, the amount of nectar they produced, and the weight of the dried flowers. They also collected information regarding visiting insect pollinators. This included their visiting patterns to both the experimental plots and the untouched ones.
The study found that there were 25 plant species and 80 insects species in 2014 and 19 and 69 in 2015, respectively. Higher temperatures and more precipitation didn’t change what species were found in the plots, with the most abundant wildflowers being corn marigold (Glebionis segetum), cornflower (Centaurea cyanus), common field-speedwell (Veronica persica), shepherd’s purse (Capsella bursa-pastoris), chickweed (Stellaria media) and red dead-nettle (Lamium purpureum).
The heated plots saw wildlife abundance drop by as much as 40%. However, there were fewer seeds in the heads of most plants and the seeds were lighter than those in nonheated plots. The common field-speedwell, a weed that is widely distributed in the generalist category, was the exception. Although it produced more seeds in the heated plots than it did in the wild, its flowers produced 65% less nectar which made it less popular among pollinators.
“A key finding [of the study] is that not all wild plant species respond to experimental manipulation in the same way, and so the implications for plant communities, and their interactions with pollinators, are complex to predict,” Stout said. Nevertheless, the general decrease in both the abundance and the number of seeds produced is of concern, she added, “because loss of floral resources in the landscape is already a major driver of pollinator decline.”
The heated plots also saw significant changes in the feeding behavior and habits of pollinators. The most abundant insects, including honeybees, hoverflies, and bumblebees visited more flowers and increased their frequency of visits to the same flower to collect nectar and pollen.
“Fewer flowers and less nectar mean less food for pollinators,” Moss said, adding that such conditions may drive competition between pollinators and force them to choose less optimal flowers. “This could reduce their fitness and survival.”
The future looks bleak for the blooms
Worldwide, two in five plantsLand use changes in agriculture, housing and construction are threatening wildflowers and other plants. California is experiencing an increasing number of droughts. Hotter and dryerResearch has shown that winters are more likely to be caused by climate change. StagnationIn 15 years, wildflower species were down 15% Human activities have caused the destruction of approximately 500,000 wildflower species in the U.K. 97% of wildflower meadowsSince the 1930s threateningWild strawberry, once a common plant, is now extinct.Fragaria Vesca), harebell (Campanula rotundifolia), and ragged robin (Silene flos-cuculi).
Wildflower loss also has an impact on thousands of insect species including bees and herbivores such as aphids. It also affects natural pest controllers like ladybirds, spiders, and lacewings who take refuge in meadows. Research shows that worldwide, there are approximately 2.6 million cases of a Quarter of all known bee speciesThey have been absent since the 1990s. Habitat loss is one of the main reasons for their decline.
“[Climate change] risks crop pollination and our own food supply, but perhaps of more concern is the risk to wild plant pollination and our ecosystems and all the other benefits we get from them,” Stout said.
The fastest way to combat climate change is to reduce emissions. However, wildflowers could still be saved by taking other steps.
“The main things that will improve ecosystem resilience in the context of wildflowers and pollinators is to improve habitat quantity, quality and connectivity,” Moss said. “We need to leave more wild spaces for native plants and insects and try to connect these areas up so that these patches of high-quality habitat are not too small or too far apart.”
Citations:
Moss, E. D., & Evans, D. M. (2022). Experimental climate warming reduces floral resources, alters insect visitation, and alters wildflower seed set within a cereal agroecosystem. Frontiers in Plant Science. doi:10.3389/fpls.2022.826205
(2020). State of the World’s Plants and Fungi 2020. Royal Botanic Gardens Kew. doi:10.34885/172
Harrison, S. P., Gornish, E. S., & Copeland, S. (2015). Climate-driven diversity loss within a grassland community Proceedings of The National Academy of Sciences 112(28), 8672-8677. doi:10.1073/pnas.1502074112
Zattara, E. E., & Aizen, M. A. (2021). Recordings of bee species worldwide suggest a decline in their diversity. One Earth, 4(1), 114-123. doi:10.1016/j.oneear.2020.12.005
Banner image: Wildflower meadow, important food source for pollinating insects. Image by Ralphs_Fotos via Pixabay.
