A paper published in the CABI Reviews journal has found that climate change is the most prominent threat to pollinators—such as bumblebees, wasps, and butterflies—that are essential for biodiversity conservation, crop yields and food security.
The research, which is titled “What are the main reasons for the world-wide decline in pollinator populations?”, suggests that many of the threats to pollinators result from human activities.
Pollinator populations are declining worldwide and 85% of flowering plant species and 87 of the leading global crops rely on pollinators for seed production. The decline of pollinators seriously impacts biodiversity conservation, reduces crop yield, and threatens food security.
According to The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), approximately 16% of vertebrate pollinators, such as birds and bats, and 40% of invertebrate pollinators, such as bees and butterflies, are at risk of extinction.
Dr. Johanne Brunet and Dr. Fabiana Fragoso, authors of the review, argue that efforts to control the various factors that negatively impact pollinators must continue given the dire consequences.
They stress that understanding the drivers of pollinator decline can guide the development of strategies and action plans to protect and conserve pollinators and the essential ecosystem services they provide.
Dr. Brunet said, “This review introduces the diversity of pollinators, addresses the main drivers of pollinator decline, and presents strategies to reduce their negative impacts.
“We discuss how managed bees negatively affect wild bee species, and examine the impact of habitat loss, pesticide use, pests and pathogens, pollution, and climate change on pollinator decline. Connections between humans and pollinator decline are also addressed.”
The researchers believe that the changes in water and temperature associated with climate change can lower the quantity and quality of resources available to pollinators, decrease the survival of larvae or adults, and modify suitable habitats.
Meanwhile, pollinators, they argue, are negatively impacted by human actions including habitat loss and degradation, the application of agrochemicals, climate change, and pollution.
The researchers say, that in the absence of pollinators, the human diet will shift towards a preponderance of wheat, rice, oat, and corn, as these are wind-pollinated crops. Crops that reproduce vegetatively, such as bananas, will be maintained.
Dr. Fragoso said, “Widespread use of sustainable practices in agriculture, and further development of integrated pollinator management strategies, eco-friendly strategies including reduction of pesticide use, will help preserve pollinators.
“Potential adverse effects of managed bees on the local wild bee populations must be mitigated. Non-lethal collection methods should be developed and adopted globally in response to the increasing need for base-line pollinator data collection.”
For those that missed it, I posted on some relevant research recently from Argonne National Lab, that tracked insect populations on Solar Fields in southern Minnesota for 4 years.
The two studied solar sites were planted with native grasses and flowering plants in early 2018. From August 2018 through August 2022, the researchers conducted 358 observational surveys for flowering vegetation and insect communities. They evaluated changes in plant and insect abundance and diversity with each visit.
“The effort to obtain these data was considerable, returning to each site four times per summer to record pollinator counts,” said Heidi Hartmann, manager of the Land Resources and Energy Policy Program in Argonne’s Environmental Sciences division, and one of the study’s co-authors. “Over time we saw the numbers and types of flowering plants increase as the habitat matured. Measuring the corresponding positive impact for pollinators was very gratifying.”
By the end of the field campaign, the team observed increases for all habitat and biodiversity metrics. There was an increase in native plant species diversity and flower abundance. In addition, the team observed increases in the abundance and diversity of native insect pollinators and agriculturally beneficial insects, which included honeybees, native bees, wasps, hornets, hoverflies, other flies, moths, butterflies and beetles. Flowers and flowering plant species increased as well. Total insect abundance tripled, while native bees showed a 20-fold increase in numbers. The most numerous insect groups observed were beetles, flies and moths.
In an added benefit, the researchers found that pollinators from the solar sites also visited soybean flowers in adjacent crop fields, providing additional pollination services.
When done right, pollinator-friendly solar farms can do much more for the environment than just generating clean energy. They can create biodiverse habitats that improve the soil, sequester carbon and potentially benefit nearby agriculture. “These solar farms can have a valuable impact on everything that’s going on in the landscape,” says Matthew O’Neal, an entomologist at Iowa State University and co-author of a recent paper discussing how solar farms can contribute to pollinator conservation.