Pollinators: critical farm workers
To bee or not to bee? That is the big question. News media across the nation have been abuzz with stories of bees and the plights they are facing. While bees and wasps are seemingly ubiquitous around us, these pollinators face many environmental stressors that threaten their populations.
Plants and pollinators exist in mutualistic relationships, each one depends on the other for its survival. Plants provide food for pollinators, particularly nectar and pollen. When pollinators visit plants in search of food, pollen collects on their mouths, beaks, antennae, wings or abdomen, and the pollen then rubs off when visiting subsequent plants. This transfer of pollen leads to plant reproduction, allowing for fertilization and the creation of fruits or seeds.
While some pollen is transferred by the wind, most of the world’s flowering plants depend on animal pollinators, like bees, to reproduce. Pollinators are critical to crop production, maintaining diverse, productive plant communities, and food that sustains people and wildlife.
Pollinators come in a wide variety of shapes and sizes. Common pollinators include bees, wasps, butterflies, moths, birds and bats.
Mary Harris, Iowa State University faculty member in the departments of Entomology and Natural Resource Ecology and Management, notes bees are the most important animal pollinators. In addition to honeybees, which were brought from Europe in the 1600s to help pollinate crops, Iowa also houses a diversity of native bee pollinators. “It’s amazing. We have over 200 species of native bees remaining in Iowa,” she says. “Historically, we likely had around 400 species.”
Different nectar and pollen sources are needed for different species of bees as the seasons change. Plants rely on certain bees to visit at specific times when they are in bloom. “Plant diversity is critical to support the diversity of native bees,” says Harris. “You need nectar and pollen sources throughout the season.”
In terms of habitat, the more wildflowers, the better; pollinators are especially drawn to these plants. Native wildflowers, shrubs and trees provide shelter and food for a diversity of wildlife, including pollinators. Minimizing ground disturbance is also important, as 80% of Iowa’s native bees are ground nesters, burrowing and building nesting tunnels underground.
Risks to pollinators
Rapidly declining pollinator populations are due to challenges in their environment. According to USDA, from 2006 to 2014 nearly a third of all bees nationwide died annually. Many pollinators are at risk due to habitat loss or fragmentation, weather extremes, disease, and parasites. Also, neonicotinoid insecticides are an emerging concern, having been shown to cause problems with bee orientation and impaired memory that reduces bees’ ability to gather food.
Maintaining pollinator populations is critical for sustaining healthy ecosystems. Pollinators, especially bees, provide a large economic value, offering free pollination, while benefiting agricultural productivity and profitability through increased yields and crop quality improvements.
Integrating small areas of native vegetation into farming operations, gardens or backyard landscaping can offer disproportionate benefits for protecting pollinators. Restored prairie, riparian buffers or grass filter strips, hedgerows, and windbreaks offer a multitude of environmental benefits, including improved wildlife habitat for song birds, game birds and insects, including crop pest enemies, as well as improving water quality and erosion control.
The USDA Natural Resources Conser-vation Service recommends minimizing tillage to protect the habitat of ground-dwelling native bees, being cognizant of pesticide rates and timing of application, and maximizing plant diversity.
Staudt is the assistant program manager with Iowa Learning Farms.
This article published in the February, 2015 edition of WALLACES FARMER.
All rights reserved. Copyright Farm Progress Cos. 2015.
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