Insect populations in Germany’s protected preserves have dramatically declined over the past 30 years, according to new research in the journal PLOS ONE.
This discovery comes from a group of European researchers who found that between 1989 and 2016 the biomass of flying insects declined by 75 percent across 63 nature reserves. In the past, most of the attention has focused on the decline of pollinators like bees and butterflies. However, the new study shows the problem may affect more species than previously thought.
“The fact that flying insects are decreasing at such a high rate in such a large area is an even more alarming discovery,” said study co-author Hans de Kroon, researcher at Radboud University in the Netherlands, in a statement.
Scientists first began collecting insects in traps — known as malaise traps — back in 1989. Since then, the devices have enabled teams to measure the total insect biomass. As the study reveals, less and less insects have been captured over time.
The decline of insect biomass during midsummer peaked at 82 percent, showing that drop-off during that time of the year is much more severe than average decline. While such shifts can be the result of weather variability, climate changes cannot account for the sharp decline noted in the research.
The team is not sure of the reason behind the decline, but they do note that over 63 of the preserves looked at in the study are surrounded by agricultural lands. Those areas — which are harmful to many insect species — could act as an “ecological trap” that hurt the insects inside the preserves.
Though the research took place in Germany, the team believes the findings are indicative of much larger trends. They hope the findings will encourage policy makers to take a closer look at global insect populations and create preserves that are not so close to agricultural land.
“As entire ecosystems are dependent on insects for food and as pollinators, it places the decline of insect eating birds and mammals in a new context,” added Kroon, according to UPI. “We can barely imagine what would happen if this downward trend continues unabated.”