When we think of animals affected by human activity, it’s often the cute, fluffy, and cuddly creatures that come to mind. Yet, if we follow the chain of what keeps everything alive- from the zebra that feeds the lion to the plants that feed the zebra- we quickly reach the architects of our global ecosystems: pollinators. These tiny insects are frequently overlooked and treated as pests, yet they play a vital role in maintaining the balance and health of our natural environments. However, this support system is now under threat, with a recent study from Sussex, England, revealing a troubling 37% decline in insect populations.
Insects, farmers, and pesticides…
Land use in the UK is dominated by farmland, with 70% being utilised for agriculture, including around 3 million hectares dedicated to cereal production alone [1]. This agricultural dominance has intensified since the 1970s, with farming practices becoming more industrialised. A recent study of cereal fields in the Sussex Downs underscores the consequences of this shift. Agricultural intensification has encouraged the use of pesticides and fertilisers to improve crop yield but at the expense of insect populations. As a result, ecosystems such as meadows and forests could collapse from the loss of key insect species and the important roles they play, such as decomposing dead organisms and being a food source for other animals.
Ewald and his colleagues highlight the profound consequences of insect declines and identify the key factors behind them. The study involved sampling insects from approximately 100 crop fields every June from 1970 to 2019 using D-VAC suction samplers – a backpack-mounted vacuum that sucks up insects! The sampling method remained consistent over 50 years, with the suction traps carefully maintained to ensure reliable data. By the end of the study, approximately 2.98 million insects had been collected and grouped based on what their function is within an ecosystem (crop pest, predator, parasite, pollinator, or decomposer). These classifications helped researchers determine which insects are thriving and those that are struggling.
The study highlights significant changes over the past 50 years. Overall, invertebrate numbers have decreased by 37%, but the picture is more nuanced. Of the 51 invertebrate groups considered, 47% showed a decline, 37% remained unaffected, and 16% actually increased in number.
One possible explanation, supported by studies on air pollution, is that agricultural intensification has harmed all species, but some are more resilient than others [2]. These hardier species can recover more quickly from the disturbances, allowing them to take advantage of the changing conditions. In essence, while all organisms are impacted, the more adaptable species thrive, leaving less room for others, potentially resulting in a shift toward less diverse ecosystems. Therefore, the rise of certain species should not downplay the risks posed by modern farming to the functionality of the ecosystems surrounding crop growth.
Think of the children!
Additionally, growing concerns for the diminishing number of farmland birds are fuelled by the results of the study, with a significant impact on species such as grey partridge, yellowhammer and skylark. It was found that 80% of insect species highlighted as a food source for farmland chicks, such as carabid beetles, are declining. Insects like beetles are essential for the early development of chicks, those with stunted growth being more vulnerable to disease and predators. Limited food sources available for growing chicks have a direct impact on bird population health, with studies in Europe supporting the connection between agricultural intensification and the increase in farmland bird fatalities [3].
Over the decades, invertebrate populations have shown a pattern of decline, partial recovery, and further decline. This demonstrates that when given the opportunity, nature can bounce back, highlighting the importance of adopting sustainable farming practices. The cry for help may be subtle, but that makes it no less severe!
How to find another way
This study makes it clear that while intensified farming has benefits for food production, it comes at a cost to biodiversity. Reducing pesticide use, planting diverse crops, and creating wildflower strips around fields are all ways that farming can better support insects. We as individuals can also aid in recovery efforts, building bug hotels, planting wildflowers and creating better mindsets towards the minibeasts of our world by encouraging children to care through arts and craft projects. Information about all of this can be found easily online, with organisations such as the Woodland Trust having step-by-step guides to help you be a better advocate for insects. By being kinder to our smaller counterparts, we can help take the creepy out of ‘creepy crawlies’ and inspire more consideration for key species. Protecting insect populations is about more than just saving individual species; protecting insects supports the very foundation of all our lives.
Article by Abi Hinchcliffe, with thanks to Fin Mills, Joe Walker, Sarah Bellis, and Maria Giulia Checchi
Photos via Unsplash: Annie Spratt, Mateusz Stepien and Seema Miah
Study Paper: Ewald JA, Potts GR, Aebischer NJ, Moreby SJ, Wheatley CJ, Burrell RA. Fifty years of monitoring changes in the abundance of invertebrates in the cereal ecosystem of the Sussex Downs, England. Insect conservation and diversity 2024; 1–30.
References:
- GOV.UK. Agricultural Land Use in United Kingdom at 1 June 2023. GOV.UK. 2023.https://www.gov.uk/government/statistics/agricultural-land-use-in-the-united-kingdom/agricultural-land-use-in-united-kingdom-at-1-june-2023.
- Dudley N, Stolton S. Air pollution and biodiversity: a review. Bristol: Montpelier. 1996
- Rigal S, Dakos V, Alonso H, Auniņš A, Benkő Z, Brotons L et al. Farmland practices are driving bird population decline across Europe. Proceedings of the National Academy of Sciences of the United States of America 2023; 120: e2216573120.
