The declines are confirmed by the All-Ireland Bumblebee Monitoring Scheme co-ordinated by Dr Tomás Murray, senior ecologist at the National Biodiversity Data Centre in Co Waterford.
Of 98 Irish wild bee species, one-third are threatened with extinction, he confirmed.
“Given the variability around our estimate, we have to be cautious about not crying wolf, but it is telling that we are detecting moderate declines in widespread species after only six years,” Dr Murray said.
“In 2017, we collectively walked 883km over 490 hours, and counted 12,969 bumblebees across 14 species, making this one of the first national citizen science schemes in the world that tracks changes in wild pollinator populations,” Dr Murray said.
Its implementation is co-ordinated by the National Biodiversity Data Centre.