Sheffield Air Quality Garden 2023 is planted!
Air Pollution and Pollinating Insects
Our pollinating insects are in trouble. Since the end of World War Two, a range of environmental changes have put pressure on these crucial contributors to our ecosystem. Changes in land use, modern industrialised farming, destruction of wildflower meadows and hedgerows, widespread pesticide use, and climate change, are all established factors in the decline of our pollinator populations. And evidence is now mounting for air pollution to be added to the list.
Many of the effects of air pollution on human health are well-established, and as our knowledge increases, the need to reduce air pollution as a matter of urgency becomes ever more clear. For the “it never did me any harm” brigade, it is worth noting that almost everybody in the UK will eventually die from heart disease, dementia, cancer, stroke, or respiratory disease. The growing body of evidence implicating air pollution as a contributing factor in all of these is disturbing. Couple that to the fact that legal air pollution limits in the UK are significantly above what the World Health Organisation considers safe, and yet are still regularly being breached, and we have what experts have called a public health crisis.
But the link between pollinator decline and air pollution is only now becoming clear. Why is pollinator decline important? Put simply, most plants require insect pollinators in order to reproduce successfully. Without pollinators, vast numbers of plants would vanish and ecosystems would collapse.
Now, nobody is suggesting all pollinators will be lost. However, what we are seeing already is a dramatic shift towards species which are generalists, able to feed from a wide range of flowers, or happen to be better suited to plant species which are becoming predominant. The biological landscape is becoming more homogenised as more specialised insect species and the plants they depend on are squeezed. Why is biodiversity important? Well, if we put aside the generally held opinion that humans causing the extinction of species we share the planet with is ‘a bit sad’, a diverse ecosystem is one which is likely to be more resilient in the face of future challenges. For example the introduction of a new disease or invasive species has the potential to upset the balance and even wipe out an existing dominant species. Where there is a lack of biodiversity, a difficulty exists in filling such a vacated ecological niche- the available candidates are limited.
In the last two years, researchers from the Universities of Reading and Melborne have found strong evidence that major air pollutants act in concert to hamper pollination. While the Reading group found that nitrogen dioxide and ozone masked the odour of flowers, making them less attractive and harder to find for insects, the Melbourne group has recently found that particulate matter blocks the odour receptors on the insects antennae. The implication is that, in areas with general poor air quality, insects ability to find their preferred food source (often specific flower species) is reduced both by masking of the flowers scent, and destruction of the pollinator’s sense of smell.
Let’s hope that measures put in place to reduce air pollution for the benefit of human health, also give our beleaguered pollinator species a much-needed boost!