By Saida Sambour

“Climate change is likely the biggest driver,” says York University associate professor Sandra Rehan of changes in plant-pollinator networks. Along with grad student Minna Mathiasson from the University of New Hampshire, she has dedicated her time to evaluate plant-pollinator networks dating back 125 years. Featured in the journal, Insect Conservation and Diversity, their research focuses on the decline of wild bees, who together with the native plants they rely on, make up these networks. 

Only six percent of the networks are functioning with pollinators like small carpenter bees. The other 94 percent of networks are either completely lost or still includes certain plants in the ecosystem but no bees.

There are major factors contributing to the loss of the plant-pollinator networks, particularly climate change. “We know that over the last 100 years or so annual temperatures have changed by two and a half degrees,” Rehan says. “This is enough to alter the time when certain native plants bloom.” Agriculture has also grown rapidly in northeastern North America, which has disrupted the peace of bee habitats over the years. Bees who have few floral hosts and rarely leave their habitat are more greatly affected by these factors.

These important findings about plant-pollinator networks could have a commercial impact. Bees are highly important for pollinating crops around the world. In fact, wild bees are responsible for more than 87 percent of the pollination of flowering plant species. Their work brings in billions of dollars in profit due to highly demanded commercial crops such as apples, which is ultimately great for the economy. If plant-pollination networks continue to decrease, the global economy could take a hit. According to the researchers, habitat restoration and native flowering plants could improve bee biodiversity and food security. 

Researchers must continue to analyze pollination to find a solution to the problem. “There is an urgent need to gain a deeper understanding of the environmental circumstances affecting these wild pollinator populations and their specialized, evolutionary relationships with plant communities,” says Rehan. “Plant pollinator webs are dependent on changes in the landscape, so knowing how these networks are shaped is important for all regional habitats.”