[permaculture] Solar Farms Shine a Ray of Hope on Bees and Butterflies - Scientific American

Lawrence London lfljvenaura at gmail.com
Sun Feb 3 12:52:50 EST 2019

Solar Farms Shine a Ray of Hope on Bees and Butterflies - Scientific

Solar Farms Shine a Ray of Hope on Bees and Butterflies
A trend of planting wildflowers on solar sites could maintain habitat for
disappearing bees and butterflies

   - By Jodi Helmer <https://www.scientificamerican.com/author/jodi-helmer/>
   on January 14, 2019

 NREL scientist Jordan Macknick and Jake Janski, from Minnesota Native
Landscapes survey a pollinator test plot planted underneath the
photovoltaic array at the Chisago Solar Site, part of the  Aurora Solar
Project in Minnesota. Credit: Dennis Schroeder National Renewable Energy
Lab Flickr (CC BY-NC-ND 2.0)

The tidy rows of gleaming solar panels at Pine Gate Renewables facility in
southwestern Oregon originally sat amid the squat grasses of a former
cattle pasture. But in 2017 the company started sowing the 41-acre site
with a colorful riot of native wildflowers. The shift was not merely
aesthetic; similar projects at a growing number of solar farms around the
country aim to help reverse the worrying declines in bees, butterflies and
other key pollinating species observed in recent years.

Up to $577 billion in annual global food production
<http://www.fao.org/news/story/en/item/384726/icode/> relies on pollination
by insects and other animals such as hummingbirds and bats, according to
the United Nations. But more than half of native bee species (pdf
in the U.S. have seen their numbers drop sharply since 2005, with almost 25
percent now at risk of extinction. Meanwhile the North American monarch
population has declined 68 percent over the past two decades, the nonprofit
Center for Biological Diversity says. Suspected factors include climate
change, pesticide use and parasites—along with shrinking habitat, largely
blamed on natural landscapes (such as scrublands or wetlands) being
converted for agricultural use.

And as pollinator habitat wanes, solar installations are taking up ever
more land. The U.S. is expected to convert six million acres of land to
such facilities before 2050 <https://fresh-energy.org/nrelwebinar/>,
according to the National Renewable Energy Laboratory (NREL). Some
researchers see this as an opportunity to reclaim land for pollinating
species by replacing the usual grass or gravel at these sites with
wildflowers that need insects to pollinate them, and that produce the
nectar those insects eat. “If we can create some habitat where there wasn’t
habitat before, like on solar farms, we can likely have a positive impact,”
says Scott McArt, an entomologist at Cornell University.
A monarch Butterfly feeds on flowers being grown for seed at Minnesota
Native Landscapes in Foley, Minn. Credit: Dennis Schroeder National
Renewable Energy Lab *Flickr*
(CC BY-NC-ND 2.0 <https://creativecommons.org/licenses/by-nc-nd/2.0/>)

More Plants = More Pollinators?

Minnesota-based Great River Energy (pdf
has also introduced pollinator-supporting plants—such as purple prairie
clover and wild lupine—at several of its solar sites, as has SoCore Energy
at some of its outfits in Wisconsin. In 2018 the NREL identified
<https://pubs.acs.org/doi/pdfplus/10.1021/acs.est.8b00020> 1,350 square
miles of land near existing and planned utility-scale solar energy
facilities around the country that could be similarly converted. Although
no national statistics are available, in Minnesota alone it is estimated
that half of the 4,000 acres of commercial solar projects installed in 2016
and 2017 included pollinator habitat

Designing such habitat is not a matter of simply scattering some wildflower
seeds, though. The right mix of a broad range of native plants is needed to
attract and support the hundreds of pollinator species, from bees to birds,
that can be found in some areas. A number of them have adapted to specific
plants—such as monarch butterflies that feed on milkweed—or are extremely
imperiled, as is the case with native bumblebees, says Sarah Foltz Jordan,
a senior pollinator conservation specialist for the nonprofit environmental
organization Xerces Society for Invertebrate Conservation. “A common issue
with pollinator habitat is that the seed mixes aren’t very diverse,” she
says. “So they may look pretty, but when you don’t have a highly diverse
plant community, you don’t support a highly diverse pollinator community.”

There is some limited evidence (pdf
solar farms with mixed plant life can support a wider array of bee and
butterfly communities than those with grass or gravel beds can, but
researchers are still investigating just how much this can affect the
insects’ long-term survival. “We don’t have the data to say whether
meaningful changes occur at a broad scale just due to solar sites,” McArt
says. “We don’t know if this is going to have a substantial impact.” But he
hopes to change that. In July, through a partnership
between Cornell and North Carolina–based solar developer Cypress Creek
Renewables, McArt launched a three-year study to determine whether—and how
much—establishing habitat on solar sites benefits pollinator populations.

The team will compare the abundance and diversity of wild bee species at a
solar site planted with native wildflowers with an installation that has
turfgrass growing beneath its panels. Then the researchers will test which
seed mixes are most effective at attracting wild bees over longer periods.
“Maybe it’s not the seed mix that looks fantastic and attracts a lot of
bees in the first year,” he notes. “Maybe the better seed mix is the one
that takes longer to establish but is much more resilient over time.”
Minnesota bee keeper, Jim Degiovanni, inspects "BareHoney" hives outside
IMS Solar, a pollinator-friendly photovoltaic array site in St. Joseph,
Minn. Credit: Dennis Schroeder National Renewable Energy Lab *Flickr*
(CC BY-NC-ND 2.0 <https://creativecommons.org/licenses/by-nc-nd/2.0/>)

Boost to Farms and Business

When solar developers consider planting pollinator habitat, they also look
at the bottom line, notes Lee Walston, an ecologist at Argonne National
Laboratory outside Chicago. Despite a higher upfront cost to purchase and
plant seed mixes, Walston contends this can actually offer long-term
savings. For example, a field of wildflowers requires less mowing and
pesticides than conventional grass does. And gravel absorbs heat whereas
plants can help keep panels cool, improving energy efficiency.

Moreover, Walston believes planting wildflowers can help garner support in
rural communities that might be resistant to leasing productive farmland to
solar developers. New research
<https://pubs.acs.org/doi/10.1021/acs.est.8b00020> has found raising
pollinator numbers can bring higher yields of crops such as fruits and
nuts, offering an obvious boon to farmers.

But one problem with siting insect-friendly solar installations next to
pesticide-using farms is the chemicals can drift onto the wildflowers.
have been shown <https://extension.psu.edu/pesticides-and-pollinators>
to impair
various pollinating insects’ foraging ability, decrease their immune
responses, interfere with their absorption of nutrients and shorten their
life spans. Mandatory buffer zones could help protect habitat from
pesticide drift, Foltz Jordan says. Ultimately, she adds, converting some
farmland to solar sites could also reduce overall pesticide use.

Still, experts warn such projects are hardly a panacea. “Establishing
pollinator habitat on solar facilities is not the answer to pollinator
decline,” says Argonne ecologist Ihor Hlohowskyj—but he believes it is
still one valuable way to prop up imperiled species. “With the large
surface areas that solar facilities occupy,” he says, “they offer a pretty
unique opportunity to plant and establish pollinator habitat that could
help conserve pollinator diversity.”

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