Data from: Gradual replacement of wild bees by honeybees in flowers of the Mediterranean Basin over the last 50 years

Evidence for pollinator declines largely originates from mid-latitude
regions in North America and Europe. Geographical heterogeneity in
pollinator trends combined with geographical biases in pollinator studies,
can produce distorted extrapolations and limit understanding of pollinator
responses to environmental changes. In contrast to the declines
experienced in some well-investigated European and North American regions,
honeybees seem to have increased recently in some areas of the
Mediterranean Basin. Since honeybees can have negative impacts on wild
bees, it was hypothesized that a biome-wide alteration in bee pollinator
assemblages may be underway in the Mediterranean Basin involving a
reduction in the relative number of wild bee pollinators. This hypothesis
was tested using published quantitative data on bee pollinators of wild
and cultivated plants from studies conducted between 1963-2017 in 13
Mediterranean countries. The density of honeybee colonies increased
exponentially and wild bees were gradually replaced by honeybees in
flowers of wild and cultivated plants. The proportion of wild bees at
flowers was four times greater than that of honeybees at the beginning of
the period, the proportions of both groups becoming roughly similar fifty
years later. The Mediterranean Basin is a world biodiversity hotspot for
wild bees and wild bee-pollinated plants, and the ubiquitous rise of
honeybees to dominance as pollinators could in the long run undermine the
diversity of plants and wild bees in the region.