Temperature change has negatively affected most species of bumble bee over the past 120 years, according to new research published this week in biology paper, The researchers note that changes in temperature had a more negative effect than other factors – such as rainfall or flower resources.
“Bumblebee bees are important pollinators for wild plants and for the crops on which humans depend for food. We therefore need to develop conservation strategies that account for the future effects of climate change on bee populations, ” says study lead Hanna Jackson, a masters student in the M’Gonigal Lab in the Biological Sciences at Simon Fraser University.
Jackson and his colleagues analyzed an existing dataset containing records of 46 bumblebee species in North America between 1900 – 2020. They created two occupancy models to estimate climate and land effects – one focused on time and the other on environmental factors. Use variables on species occupancy, a measure of where the species is found. They found that six species of bumblebees decreased over time, 22 increased and the remaining 18 remained stable.
They note that both temperature and precipitation have increased, on average, between 1900 and 2020, in the period following the Industrial Revolution. Temperature change had a predominantly negative effect on bumble bees, with 37 of the 46 species exhibiting a greater decline or less positive increase in occupancy than the change in temperature, if the temperature had remained constant.
Importantly, nine species of bumble bee exhibited declines that are associated with changing temperatures within their ranges. The team didn’t find patterns in the other factors studied, such as rainfall and flower resources in which only one species declined.
In fact, both flower resources and rainfall had mixed results. About half of the bumblebee bee species were negatively affected by rainfall or changes in flower resources, while the other half were positively affected.
Therefore, the researchers conclude that changing temperatures are a major environmental factor that drives changes in bumble bee community composition.
“As bumble bee species differ in land use and future responses to climate change, conservation action must prioritize individual species, taking into account their unique climate and habitat preferences,” Jackson says.
Study collaborators include the US-based Pollinator Partnership, the Gerris Society for Invertebrate Conservation and the Department of Biological Sciences at the University of Southern California.
material provided by Simon Fraser University, Original written by Melissa Shaw. Note: Content can be edited for style and length.