The flowering shrubs and bushes that edge fields of crops in Yolo County not only look nice.

Research by Claire Kremen at UC Berkeley is assessing whether these hedgerows can help farmers by supporting the lives of native pollinating insects.

Farmers usually truck in white boxes of honeybees to pollinate the blueberries, almonds and avocados that need it. But honeybees are expensive, and their colonies are in decline.

As Kremen describes it, they are "a weak link in the food system."

Even though there are nearly 300 species of native bees in Yolo County, they and other native pollinators can't live on the farms where they're needed. The habitat isn't right for them.

"They can't nest (underground) in that field, because they'll get tilled," said Leithen M'Gonigle, postdoctoral researcher with Kremen.

And while fields of single crops, like sunflowers, provide food for only the short period they're in bloom, insects need flower nectar yearlong.

"Just like us, we can't survive on one food type," said Kremen.

"It's kind of a double whammy," she said. Though the crops can't fully support the pollinators, they still need them in immense quantities and quick bursts.

Kremen, a 2007 recipient of an esteemed MacArthur Foundation grant, has been studying ways for farmers to bring pollination services back on their own land.

One way is a hedgerow, where native California plants line a field of crops.

Planted for a range of flowering periods, a hedgerow can be in bloom – and be a source of nectar – from early spring until fall. This might support native insects in addition to giving them a safe place to nest underground.

"It seems intuitive that these hedgerows … have to help," said M'Gonigle. "We have to actually show that and quantify it."

"We already know that we have a greater diversity of pollinators … on hedgerows than weedy edges," said Kremen.

Through studies she will continue over the next several years, she hopes to determine whether hedgerows will sustain native pollinators.

So nearly every summer day, when flowers are in bloom, Kremen's researchers monitor dozens of farms near Davis, some with hedgerows and some without.

They start early to avoid the heat. Each at a different farm, they are equipped with a box of supplies, a net, a wide-brimmed hat and a fanny pack.

They slowly pace along the borders of fields, swiftly swooshing their nets when they find a native insect pollinating a flower.

Then they carefully get it into a tube from their fanny pack so that they can send it to a specialist to be identified.

"That's a nice native bee," said M'Gonigle as he inspected his collections.

During the day, they continue collecting insects for a set period of time. "Field work is never particularly glorious," said M'Gonigle.

"You sort of get in the zone."

Next they'll compare the species and their counts between hedgerow sites and weed sites to see if over time, hedgerows support more native pollinators.

Kremen is "really getting to some bottom-line figures that people want to see for this kind of work," said Jessa Guisse of the Xerces Society, an invertebrate conservation organization.

Kremen's research and farmers' experiences with hedgerows have already demonstrated their benefits.

More than 20 years ago, Rachael Long, farm adviser at UC Cooperative Extension, was inspired by a visit to John Anderson's aptly named Hedgerow Farms in Winters. "Jeepers, not only do we enhance biodiversity, but we can change our landscape to favor beneficial insects," she recalled thinking.

Hedgerows may improve water quality and provide corridors and nesting habitats for other animals.

His farm, which has had hedgerows since the '80s, is not a part of Kremen's research, but Anderson said "wildlife abounds here," citing quail, turkeys, songbirds, snakes and lizards.

Long has found hedgerows to double the number of bird species. "They bring a lot of energy and life to an … area that may just have had weeds," she said.

Frank Muller of Joe Muller and Sons in Woodland said they have used fewer pesticides as a result of beneficial insects in their farm's hedgerows.

Hedgerows and their native pollinators may not completely eliminate the need for honeybees. But in another study, Kremen found honeybees to somehow be more efficient when native pollinators were around.

"When you read about it happening somewhere else, you just don't have that base of understanding," said Muller, who collaborates with Kremen and offers his farm as a field site. "But when it's happening on your own farm, on your own hedgerows, it makes it a lot more real."

"The research that they do is a key part of the continuum," said Jeanette Wrysinski, executive director of the Resource Conservation District of Yolo County. The organization offers classes and workshops and helps to secure farmer funding for conservation projects like hedgerows.

"The great thing about these hedgerows is that they promote conservation of these species (like native pollinators) at the same time as they're really building the stability of the agricultural system," said Kerry Cutler, Kremen's lab manager at Berkeley.

Yet Kremen acknowledged that "as long as we stick with monoculture, I don't think the hedgerow alone will be much of a solution."

"For human survival, we really need to maintain biodiversity because it has a lot of benefits," she said.

She also spoke of intrinsic value.

"These species are the product of millions of years of evolution. They have a right to exist."

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