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Tropentag, September 20 - 22, 2023, Berlin

"Competing pathways for equitable food systems transformation:
trade-offs and synergies"

Widespread declines of formerly abundant species drive insect loss

Roel van Klink1, Diana Bowler2, Jonathan Chase1

1German Centre for Integrative Biodiversity Research, Department of Biodiversity Synthesis, Germany
2Centre for Ecology and Hydrology, United Kingdom


Our human lives are intricately entwined with those of insects, as we rely on them for crop pollination and decomposition, while other insects are among our most feared crop pests and disease vectors. Yet, we know close to nothing about the status and trends of most insect species.
But what we do know is reason for concern. Using meta-analytical methods, we have previously shown that declines of terrestrial insect abundances are widespread. What remains unclear, however, is whether other aspects of biodiversity, such as species numbers, evenness and relative abundances, are also changing. We compiled long-term insect monitoring data to study global patterns of insect biodiversity change. We found that despite declines in abundances, there is only a small loss in local species numbers, whereas evenness is increasing. These contrasting patterns can be explained by disproportionate declines of dominant species and high rates of species replacement of rare species. The loss of formerly common species can explain declines in insect abundances. Given the ecological importance of dominant species, their disproportionate declines have probably already led to the widespread rewiring of food webs and changes in ecosystem functioning and services.
To do a better job of identifying such alarming levels of biodiversity loss in the future, we need new, standardised monitoring programs. Fortunately, technological advances will soon allow us to upscale insect monitoring to unprecedented levels of taxonomic and spatial coverage. DNA barcoding, computer vision, automated acoustic surveys, lidar and radar may be drawn upon to enhance ecological research and monitoring for insect conservation.

Keywords: Biodiversity loss, insects, long-term, monitoring

Contact Address: Roel van Klink, German Centre for Integrative Biodiversity Research, Department of Biodiversity Synthesis, Puschstrasse 4, 04229 Leipzig, Germany, e-mail: roel.klink@idiv.de

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