Most of Europe's wild bee species and roughly half of its hover fly species have declined over the past century, according to a study released as a United Nations biodiversity summit opens in Armenia. Records dating back to 1921 show that more bee species are declining than increasing in every part of Europe except the Alpine region, a pattern that researchers describe as a crucial opportunity to act.
The study found that the richness of bee and hover fly species suffered a persistent drop in the Atlantic and Continental regions of Europe. Trends in other regions were mixed, and some even showed positive signs, but the overall picture across the continent is one of widespread loss among these key pollinators. The findings draw on more than a hundred years of recorded observations, giving an unusually long view of how insect populations have changed.
The release coincides with the start of Cop17, the UN biodiversity summit being held in Armenia. The timing places the study's findings directly in front of policymakers at a moment when national governments are expected to assess progress on protecting ecosystems and the species that sustain them. Pollinators such as wild bees and hover flies are central to that agenda because of the role they play in plant reproduction and, by extension, in agriculture and food systems.
The regional differences in the data are notable. The Alpine region stands out as the exception, with no overall decline in bee species recorded there. The Atlantic and Continental regions, by contrast, show a sustained erosion of species richness over the decades covered by the records. The study's authors and conservation groups have framed the results as evidence that action is still possible, rather than as a verdict of irreversible loss.
Wild bees and hover flies are among the most closely monitored insect groups in Europe, which is why long-running records exist for them at all. Their sensitivity to changes in land use, habitat availability and climate makes them useful indicators of the broader health of terrestrial ecosystems. A decline in the number of species present in a region can weaken the resilience of pollination networks, with consequences that ripple through wild plant communities and cultivated crops alike.
The study does not offer a single explanation for the trends it documents, and its regional results vary in direction and strength. What it does establish is a continent-wide pattern: in most of Europe, the balance of evidence points toward fewer bee species thriving than before. That conclusion arrives as delegates in Armenia begin negotiations over biodiversity targets, giving the summit a concrete scientific backdrop against which commitments can be measured.
For conservation policy, the findings add weight to arguments for habitat restoration, monitoring programs and coordinated action across national borders, since insect populations do not respect the regional boundaries used to organize the data. The Alpine exception may also offer clues about which conditions allow pollinator communities to remain stable, though the study's scope does not settle that question. What is clear is that the long record now available shows a broad and persistent decline in most of Europe, and that the summit in Armenia provides a near-term opening for governments to respond.
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