Quantcast

Farms with just one or a handful of different crops encourage fewer species of pollinating and pest-controlling insects to linger, ultimately winnowing away crop yields, according to a new study.

Up to half of the detrimental impacts of the "landscape simplification" that monocropping entails come as a result of a diminished mix of ecosystem service-providing insects, a team of scientists reported Oct. 16 in the journal Science Advances.

Monocrop palm oil plantation Honduras.

SHARE Foundation / Flickr / CC BY-NC 2.0​

"Our study shows that biodiversity is essential to ensure the provision of ecosystem services and to maintain a high and stable agricultural production," Matteo Dainese, the study's lead author and a biologist at Eurac Research in Bolzano, Italy, said in a statement.

It stands to reason that, with declines in the sheer numbers of insects that ferry pollen from plant to plant and keep crop-eating pests under control, these services will wane as well. But until now, it hasn't been clear how monocultures affect the number and mix of these species or how crop yields might change as a result.

Aiming to solve these questions, Dainese and his colleagues pulled together data from 89 studies cutting across a variety of landscapes, from the tropics of Asia and Africa to the higher latitudes of northern Europe. They tabulated the number of pollinating and pest-controlling insects at these sites — both the absolute number of individuals and the number of species — along with an assessment of the ecosystem services the insects provided.

In almost all of the studies they looked at, the team found that a more diverse pool of these species translated into more pollination and greater pest control. They also showed that simplified landscapes supported fewer species of service-providing insects, which ultimately led to lower crop yields.

The researchers also looked at a third measure of the makeup of insect populations — what they called "evenness." In natural ecosystems, a handful of dominant species with many more individuals typically live alongside a higher number of rarer species. The team found as landscapes became less diverse, dominant species numbers dwindled and rare species gained ground. This resulting, more equitable mix led to less pollination (though it didn't end up affecting pest control).

"Our study provides strong empirical support for the potential benefits of new pathways to sustainable agriculture that aim to reconcile the protection of biodiversity and the production of food for increasing human populations," Ingolf Steffan-Dewenter, one of the study's authors and an animal ecologist at the University of Würzburg in Germany, said in the statement.

The scientists figure that the richness of pollinator species explains around a third of the harmful impacts of less diverse landscapes, while the richness of pest-controlling species accounts for about half of the same measure. In their view, the results of their research point to the need to protect biodiversity on and around crops in an uncertain future.

"Under future conditions with ongoing global change and more frequent extreme climate events, the value of farmland biodiversity ensuring resilience against environmental disturbances will become even more important," Steffan-Dewenter said.

Reposted with permission from our media associate Mongabay.

Insects like bees, butterflies and even certain species of beetle and ant incidentally pollinate our crops when they collect protein-rich pollen and sugary nectar. Rolf Dietrich Brecher / CC BY 2.0

By Kerstin Palme

Creepy-crawlies are among the oldest life forms on this planet. Before dinosaurs ever walked the earth, insects were certainly already there. Some estimates date their origins to 400 million years ago. They're also extremely successful. Of the 7 to 8 million species documented on Earth, around three quarters are likely bugs.

But several insect species could disappear for good in the next few decades and that would have serious consequences for humans.

Read More Show Less

EcoWatch Daily Newsletter

Strips of native prairie grasses planted on Larry and Margaret Stone's Iowa farm protect soil, water and wildlife. Iowa State University / Omar de Kok-Mercado, CC BY-ND

By Lisa Schulte Moore

Iowa's first-in-the-nation caucuses bring the state a lot of political attention during presidential election cycles. But in my view, even though some candidates have outlined positions on food and farming, agriculture rarely gets the attention it deserves.

Read More Show Less
Scientists in Saskatchewan found that consuming small amounts of neonicotinoids led white-crowned sparrows to lose significant amounts of weight and delay migration, threatening their ability to reproduce. Jen Goellnitz / Flickr

By Julia Conley

In addition to devastating effects on bee populations and the pollination needed to feed humans and other species, widely-used pesticides chemically related to nicotine may be deadly to birds and linked to some species' declines, according to a new study.

Read More Show Less
A beekeeper at work in Thousands Oaks, California in June of 2015. Joe Kohen / Moment Mobile / Getty Images

By Jon Queally

A group of beekeepers joined forces on Friday against Trump's U.S. Environmental Protection Agency (EPA) by filing a lawsuit over the agency's move to put a powerful insecticide — one that scientists warn is part of the massive pollinator die-off across the U.S. — back on the market.

Read More Show Less
On Oct. 1, 2017, GLOBAL 2000 projected the names of all Austrians who signed the European Citizens' Initiative "Stop Gylphosat" on the façade of the Chancellery. GLOBAL 2000 / Christopher Glanzl

Use of glyphosate will be banned in Germany from the end of 2023, after a phased effort to reduce its application by farmers.

Read More Show Less
Sponsored
A man spreads pesticides on a plantation of vegetables in Rio de Janeiro Brazil. Ze Martinusso / Moment Open / Getty Images

By Jessica Corbett

Pointing to the deaths of more than half a billion bees in Brazil over a period of just four months, beekeepers, experts and activists are raising concerns about the soaring number of new pesticides greenlighted for use by the Brazilian government since far-right President Jair Bolsonaro took office in January — and the threat that it poses to pollinators, people and the planet.

Read More Show Less

blueflames / E+ / Getty Images

By Jake Johnson

The rapid and dangerous decline of the insect population in the United States — often called an "insect apocalypse" by scientists — has largely been driven by an increase in the toxicity of U.S. agriculture caused by the use of neonicotinoid pesticides, according to a study published Tuesday in the journal PLOS One.

Read More Show Less
Beekeeper Jeff Anderson works with members of his family in this photo from 2014. He once employed all of his adult children but can no longer afford to do so. CHRIS JORDAN-BLOCH / EARTHJUSTICE

By Jessica A. Knoblauch

It's been a particularly terrible summer for bees. Recently, the U.S. Environmental Protection Agency (EPA) announced it is allowing the bee-killing pesticide sulfoxaflor back on the market. And just a few weeks prior, the USDA announced it is suspending data collection for its annual honeybee survey, which tracks honeybee populations across the U.S., providing critical information to farmers and scientists.

Read More Show Less

By Michiel de Gooijer

Read More Show Less
U.S. Department of Agriculture Agricultural Research Service entomologist Dr. Jeff Pettis examines a bee colony in California. Smith Collection / Gado / Getty Images

The U.S. Department of Agriculture's (USDA) annual honeybee count has fallen victim to budget cuts, CNN reported Saturday.

Read More Show Less
Sponsored