Words by Mansi Tailor, Staff Writer

A new study conducted by researchers at the University of Sussex and published in the Journal of Applied Ecology found that weeds deemed “injurious” actually attract more insects than the wildflowers recommended by the government. Dr Nicholas Balfour and Professor Francis Ratnieks led the study and focused on how these weeds contribute to the local biodiversity. 

An “injurious’ weed is any weed that has been designated by an agricultural or a governmental  authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, and humans or livestock

Moreover, the study demonstrates that these “injurious” plants are beneficial for biodiversity and pollinators.

In the UK, certain species of wildflowers are considered “injurious weeds” and are under the government’s control. This branding comes from the Weeds Act of 1995.

The act allows the Minister of Agriculture, Fisheries and Food to order any individual on whose land such “injurious” weeds grow to do the necessary to ensure that the weeds do not spread. 

The weeds thus targeted for control are Spear Thistle, Creeping or Field Thistle, Curled Dock, Broad-Leaved Dock and Ragwort.

A study conducted in 2019 found that a third of bee and hoverfly species in the UK had declined between 1980 and 2013. This was attributed to habitat loss and excessive pesticide use.

To address the situation moving forward, the UK’s Department for Environment, Food and Rural Affairs (DEFRA) decided on certain plants to be beneficial for insects and pollinators alike, such as Red Clover and Wild Marjoram.

The researchers conducted a study to qualify the validity of these government approved wildflowers.

They observed how insects interacted with certain wildflowers in six pastures in Sussex. These flowers included the “injurious” Thistles and Ragwort, as well as the DEFRA recommended plants.

The researchers found that the number of insects that visited the “injurious” flowers were twice that of the insects visiting the DEFRA recommended flowers. A further analysis found that these “injurious” weeds were inviting four times more pollinators and five times more the insects being targeted for conservation.

The researchers concluded the reasons behind the insects’ and pollinators’ preferences: that the “injurious” weeds grow in many places and are thus more accessible, the shape of the flowers makes it easier to collect nectar, and that these wildflowers produce four times more nectar than the DEFRA species.

“Pollinators are crucial to maintaining global biodiversity, ecosystem resilience and agricultural output. However, there are significant concerns about pollinator declines and the long-term decline of flowers in our landscapes is considered a key factor,” Balfour said in the press release. “We appreciate that agricultural weeds can cause yield losses in arable and pastureland. However, we’ve shown that they can also be of great value to both flower-visiting and herbivorous insects – and shouldn’t be underestimated when it comes to supporting our natural biodiversity.”

Freedom of Information requests discovered that the government is spending around £10 million controlling the weeds that are helpful to agriculture and biodiversity, while it spends about £40 million each year promoting the recommended DEFRA plants.

“It is alarming that the many public bodies are using tax-payers’ money and volunteers to actively remove ragwort,” Balfour said in the release. “This plant was found to support the most conservation-listed insect species in our study.”

The UK has an opportunity to change its policy as it is in the process of introducing a new scheme for farmers in England by the end of 2024, as it departs from and replaces EU policies.

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