After a lot of hearsay on vanishing bees, here come two very credible research papers showing that climate change constricts vital bees’ natural range. Warmer temperatures threaten the survival of bumblebees by significantly reducing the habitats in which they can survive.
Plants and their bee pollinators show different responses to climate change. Further increases in temperature will widen the time between bees and flowers emerging. New research reveals that rising temperatures are causing bees to fly before flowers have bloomed, making pollination less likely.
To adapt to climate change there is a general trend for species to shift their ranges poleward, or to elevate to higher altitudes. However, not all species can make such shifts, and these less climate-adaptable speciesexperience more rapid declines. Unlike other insects, such as butterflies, bumblebees are not migrating further north in search of cooler places to live. Instead, their habitat ranges are being squeezed and their populations dwindling.
One comprehensive study with a 110 year database containing more than 420,000 observations of 67 different European and North American bee species, indicates that warming is having a greater impact than pesticides or land use change.
The researchers analysed the bee observations, along with annual climate information from 1900 to 2010 in the regions, to draw conclusions about how the northern and southern limits of different bumblebee species have shifted over the past century. They then compared population changes from 1974 onwards (when temperatures began to warm), with changes from 1901 to 1974 (when anthropogenic climate change was less of a factor). The southernmost range of bumblebees retreated north about 300km in both Europe and North America.
It’s remarkable how similar the climate change susceptibility is for bees across the two continents. But distressing when you consider how vital bees’ pollination services are to our plants and food crops.
It is not clear that these two major research pieces can say that a two-degree Celsius climate change caused these patterns, likely there is a correlative relationship, but it may not be causal. Common pesticides and habitat losses have caused huge losses in bee populations. Neonicotinoid pesticides are only one of several likely factors that have been linked to declining bee populations. There are simply fewer flowers, for example, thanks to land development. Bees are increasingly dying because of mites, viruses, fungi, and other pathogens.
Bees are losing ground, and losing their habitats, to climate change. Agriculture, urban development, and land use policies need to enact measures to prevent bees from dying and honeybee colonies from collapsing. We need their ecosystem and pollination services
Climate change has narrowed the range where bumblebees are found in North America and Europe in recent decades. The paper, published in the journal Science, suggests that warming temperatures have caused bumblebee populations to retreat from the southern limits of their travels by as much as 190 miles since the 1970s. Logic would suggest that the northern reaches of their home turf would shift to higher latitudes by a corresponding distance. But that has not happened, leading researchers to think that the more northern habitats may be less hospitable to them. Bumblebee species across Europe and North America are declining at continental scales.