How a Rooftop Meadow of Bees and Butterflies Shows N.Y.C.’s Future

Tall grasses glow in the afternoon sunlight. The last bees and butterflies of the season hover over goldenrod and asters. Silver orbs that look like alien spacecrafts shimmer nearby.

The wild-looking meadow is not in a rural outpost, but sandwiched between a sewage plant — the orbs are the tanks — and a parking lot packed with tractor-trailers. The plants perch atop the roof of a film production studio in the Greenpoint section of Brooklyn, beside a Superfund toxic-waste site.

As bird and insect populations plummet, sounding new alarms about the health of the natural world, one promising arena where humans can help is also a surprising one: cities. In New York, scientists and officials are calling for residents and companies to do their part, with projects as ambitious as the rooftop meadow and as simple as choosing native plants for home window boxes.

For some species, scientists say, cities can be more hospitable than rural and suburban areas, because fewer lawns and farms mean fewer pesticides. The green roof in Brooklyn, Kingsland Wildflowers at Broadway Stages, draws endangered monarch butterflies, a panoply of birds and wild bees that are native to New York City but threatened by what scientists have called an “insect apocalypse.”

Measures to help wildlife survive in, and migrate through, cities overlap with those needed to protect people from the impact of climate change and the related flooding.

Green roofs like the one in Greenpoint, for instance, are expected to multiply under a city law that is set to take effect next month and will require new buildings to be topped with green spaces or solar panels. Either measure can help reduce carbon emissions and rising temperatures; green roofs also reduce storm-water runoff. Currently, the 730 green roofs in New York cover just 60 of the city’s 40,000 rooftop acres, according to the Green Roof Researchers Alliance.

“Cities have so much potential for creating natural habitats,” said Alixandra Prybyla, science director for the Honeybee Conservancy, a group that is expanding its activities to include the protection of wild bees.

There are 2.9 billion fewer birds in the United States and Canada than there were 50 years ago. Over 20 years, America’s monarch butterfly population has declined 90 percent, and the number of bumblebees has dropped nearly as much. The declines could be a harbinger of broader ecological collapse, and the disappearance of pollinating creatures threatens the food supply.

But in the same way that “wildlife corridors” created by countries like Indonesia and India have helped protect large animals like tigers, smaller spaces in cities can be corridors and archipelagos of green space for birds and insects.

Other measures can be as sophisticated as designing windows to prevent bird collisions, as a proposed city law would require, and as simple as choosing native plants for roadsides, gardens and parks or leaving patches of bare soil where ground-dwelling bees can burrow.

Such spaces also help people by reducing storm-water flooding and dangerous urban heat islands, asphalt-covered areas that retain the sun’s energy and get much hotter than their surroundings.

Much of New York City’s potential in this regard remains untapped, experts say. But the law taking effect next month could change that.

With it, New York will join cities like Chicago, Denver and San Francisco, which use requirements or tax incentives to promote the development of green roofs. New York State also recently increased the value of the tax abatements it offers for such roofs in some city neighborhoods.

Real estate groups argue that requiring green roofs is too expensive and burdensome for property owners. The solution that environmental activists consider ideal — charging properties for the amount of storm-water runoff they produce, and creating incentives for installing green roofs to reduce such runoff — is often called a “rain tax” by opponents.

But many animals thrive in urban settings, adapting to them over generations, or using them creatively, like Ms. Prybyla’s favorite, a hive of honeybees that started producing red honey. It turned out that the bees had discovered vats of red syrup in a maraschino cherry factory in Brooklyn’s Red Hook neighborhood.

“We want to challenge what people think belongs in an urban ecosystem,” said Guillermo Fernandez, the Honeybee Conservancy’s executive director. “People think only the hardiest rat or pigeon could live in our city, but then we start hearing about hawks and even sometimes deer and coyotes roaming through.”

It is difficult to quantify the effect of wildlife corridors, scientists say, because it is hard to isolate their impact from that of other environmental factors. But research so far shows that such corridors increase the number of species and individual creatures able to thrive in cities, and that even a patchwork of habitats can act as steppingstones, especially for flying creatures.

Not everyone can build a meadow like the one at Broadway Stages. It cost $700,000 to build 22,000 square feet of green roof, with $300,000 more going to New York City Audubon and the Newtown Creek Alliance for the community education programs that bring people to the rooftops. The seed money came from the settlement of a state lawsuit against Exxon Mobil over its pollution of the creek.

Broadway Stages spent another $500,000 to shore up the roofs. It is planning 60,000 square feet of green roofing on other buildings in Greenpoint.

Marni Majorelle, whose company, Alive Structures, designed and installed the Greenpoint roof, said that for now most of her projects are smaller green roofs atop the luxury homes of “the 1 percent.”

“That is not where big change can be made,” she said, adding that large industrial roofs could make a bigger difference. “I wish more property owners would follow suit.”

The Greenpoint project can have a calming effect on humans, too. School visits, community science projects and parties regularly bring workers and residents to the roofs.

Standing in coveralls amid nodding wildflowers, overlooking a truck parking lot, Ms. Majorelle said she had expected some that of the “tough union guys” who work in the neighborhood to wonder, “Why’d you put all those weeds up on the roof?”

Instead, she said, a studio-set worker told her recently, “I was up there and the grass was swaying, and I had a moment. I felt peaceful.”