Diversity of bees is essential to ecosystems • Earth.com

Due to a variety of factors, including habitat loss and the use of pesticides, many bees are currently at risk, along with the plants that depend on them for pollination. Now, a research team led by Rutgers University has discovered that simply saving more bees may not be enough to solve these problems. According to experts, the biodiversity of bee populations is essential for maintaining the ecosystem function of crop pollination.

“We found that biodiversity plays a key role in the stability of ecosystems over time,” said study lead author Natalie Lemanski, a postdoctoral fellow in ecology, evolution and natural resources at Rutgers. “You actually need more bee species to get stable pollination services over a growing season and over years.”

By studying diverse bee populations on dozens of farms in New Jersey, Pennsylvania and California, researchers found that different species of bees pollinate the same types of plants at different times of the year and that different species of bees were the dominant pollinators on the same type of plants in different years. Thus, due to natural fluctuations in bee populations, all of these bee species were needed to maintain a minimum threshold of pollination, especially during lean years.

“This research shows that the abundance [of a species] matters, but bee diversity matters even more,” said Michelle Elekonich, deputy director of the National Science Foundation’s Biological Sciences Branch Division, which funded the research. “It’s not the same bees that are abundant at any given time, and variety is needed to maintain balance over a growing season – and from year to year.”

These findings offer evidence for what ecologists call the “insurance hypothesis,” according to which ecosystems benefit most when nature “diversifies the portfolio,” supporting multiple animal or plant species rather than relying on one species. dominant.

“We found that two to three times as many bee species were needed to achieve a target level of crop pollination during a growing season compared to a single date,” Dr. Lemanski reported. “Similarly, twice as many species were needed to ensure pollination over a six-year period compared to a single year.”

“The magnitude of increase in species needed over multiple years was remarkably consistent across cropping systems when considered over the same time interval. Additionally, the fact that the relationship between time scale and number of needed species has not stabilized suggests that even longer time series, spanning multiple seasons, may further reinforce the need for biodiversity to deliver a reliable ecosystem service,” she concluded.

The study is published in the journal Nature ecology and evolution.

By Andrei Ionescu, Terre.com Personal editor