Insect Biodiversity Declines and Ecosystem Impact

Decades of research reveal alarming declines in insect diversity and abundance across biomes worldwide. These declines are driven by habitat loss and fragmentation, agricultural intensification and pesticide use, climate change, invasive species and urbanisation. The loss of insect biomass, species richness and occupancy disrupts essential ecosystem functions such as pollination, nutrient cycling, biological pest regulation and food provision for higher trophic levels. Emerging evidence highlights that trends vary among species, with habitat specialists, larger-bodied taxa and cold-adapted insects most at risk. Temporal and spatial changes in land use and temperature exacerbate these patterns, leading to cascading impacts on ecosystem resilience and services. Restoration of semi-natural habitats, reduction of chemical inputs and adaptive management in both forests and agricultural landscapes have demonstrated potential to mitigate declines, underscoring the urgent need for integrated conservation strategies at local, regional and global scales.

Research from Nature Portfolio

Long-term monitoring in forest ecosystems shows that declines in insect communities are mediated by species’ life-history traits and by forest management practices. Larger and more abundant species, as well as those at higher trophic levels, have declined most markedly, while herbivorous groups have sometimes increased. Sites with high proportions of non-native trees and intensive timber harvesting exhibit stronger losses, suggesting that promoting native tree composition and moderating harvest intensity can help reverse downward trends. In parallel, an analysis of four decades of distribution records across butterflies, grasshoppers and dragonflies reveals climate warming as the key driver of long-term occupancy changes: warm-adapted species have expanded their ranges, whereas cold-adapted specialists have contracted. Short-term distribution shifts further reflect interactive effects of regional land-use change and temperature anomalies, emphasising the need for climate-adaptive land management to safeguard insect diversity in temperate regions.

Insect Biodiversity Declines and Ecosystem Impact publication trend

The graph below shows the total number of articles in insect biodiversity declines and ecosystem impact across all publications each year (not limited to Nature Index journals).

Technical terms

Biomass: The total mass of living insects in a defined area, serving as an indicator of ecological productivity.

Species richness: The count of distinct insect species in a community, reflecting its biodiversity.

Occupancy: The proportion of surveyed locations where a species is present, used to track distributional changes.

Trophic level: The position of an organism within a food web, indicating its role as producer, consumer or predator.

Functional traits: Characteristic features of species—morphological, physiological or behavioural—that influence their ecological roles and vulnerability to change.

Species sensitivity distribution: A statistical model that describes variation in species’ responses to a stressor, used to estimate hazardous concentrations affecting a given fraction of taxa.

References

1. Insect decline in forests depends on species’ traits and may be mitigated by management. Communications Biology (2023).
2. Different roles of concurring climate and regional land-use changes in past 40 years’ insect trends. Nature Communications (2022).
3. Species Sensitivity Distribution (SSD) profiles towards λ-cyhalothrin for key ecosystem service provider (ESP) species across five European countries representing different pedoclimatic zones. The Science of The Total Environment (2024).
4. A global dataset of diel activity patterns in insect communities. Scientific Data (2024).
5. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLOS ONE (2017).