New framework aims to assess global insect biodiversity changes

A collaborative team of scientists from South Africa and the United Kingdom has unveiled a pioneering synthesis framework designed to facilitate the rapid assessment of changes in insect biodiversity.

This vital step comes at a time when insect populations face unprecedented declines globally, raising urgent questions about causes, urgency of action, and, ultimately, the future of our ecosystems.

In their recently published review article in the prestigious journal Science, the researchers highlight the alarming yet poorly understood trends affecting insect biodiversity worldwide.

"We know that insect biodiversity is changing, and that there have been many declines in parts of the world," the article notes. "However, we do not know how severe or pervasive the problem is. More critically, we lack a clear understanding of why insect biodiversity is changing.”

Prof. Cang Hui, a biomathematician from Stellenbosch University’s Department of Mathematical Sciences and one of the co-authors, stressed the urgency of the situation.

“We cannot wait decades for comprehensive monitoring data. The Kunming-Montreal Global Biodiversity Framework set an ambitious goal to restore biodiversity by 2050: to achieve this, we need to understand what scale of actions will be required to reverse historical declines,” he explained.

The initiative, part of the Global Insect Threat-Response Synthesis (GLiTRS) project, is supported by the National Environmental Research Council Highlight Topics program. It comprises a consortium of six institutions across the UK and South Africa, aiming to develop a global threat-response model that integrates multiple lines of existing evidence rather than waiting for more complete datasets.

"The urgency of the situation demands that we make better use of the data that is available now, however limited," the authors assert in their review. They synthesise four lines of evidence to tackle the assessment challenge: time series data, spatial comparisons, experimental observations, and expert opinion.

The role of mathematical ecology is crucial in discerning trends from time series and spatial data. Prof. Hui elaborates: “Insect time series exhibit intermittent fluctuations, yet they are both temporally autocorrelated and spatially synchronised. If we can determine the correct spatial and temporal scales, we may be able to extrapolate these trends to unsampled areas and future periods.”

Dr Rob Cooke, an ecological modeller at the United Kingdom Centre for Ecology and Hydrology and joint lead author of the study, reinforced this ambitious approach. "We need to find out whether insect declines are widespread and what’s causing them. The challenge is like a giant jigsaw puzzle where there are thousands of missing pieces, but we do not have decades to wait to fill these gaps and then act.”

Concluding the critical discourse, Dr Charlotte Outhwaite from the Zoological Society of London’s Institute of Zoology highlights the indispensable role of insects within ecosystems. “Insects are an incredibly important part of our ecosystems, pollinating around 80% of flowering plant species and vital for 35% of global food production, yet they are undervalued and understudied.”

Did you know?

• Insects dominate animal life on Earth, matching the combined biomass of all humans and livestock, around 1 billion tons.
• Threatened by 52 human-made factors, including climate change and pollution, insects face dire challenges.
• Out of approximately 1 million described insect species, only 1.2% have been assessed for extinction risk by the IUCN, with a quarter classified as Data Deficient.
• Insects constitute up to 90% of all multicellular animal species, and an estimated 5.5 million insect species remain undiscovered.