Although establishing pollinator habitats on individual farms is important, stitching together a critical mass of safe, appropriate places for fragile species to find food, shelter, and nesting sites is essential.

It’s not just that habitats are disappearing; the distance between them is increasing, making it harder for pollinators to make long treks. Fragmentation, which breaks up continuous stretches of habitat, might be as devastating to pollinators as losing their homes altogether — but the effects are under-studied.

Research shows that bats that roost in tree cavities are more vulnerable to fragmentation than cave-roosting species; some species of bats decline in response to fragmentation, but others thrive. The abundance of pollinator species is lower in fragmented habitats, which might lead to lower fruit- and seed-setting in smaller habitats, limiting pollination.

Habitat fragmentation is especially troublesome for monarch butterflies. The featherweight pollinators travel up to 100 miles per day during their annual migration from eastern North America to the Sierra Madre mountain range in Mexico or from western North America to California. During the arduous trek to their overwintering sites, the iconic black, orange, and white butterflies depend on roosting sites. Illegal logging in the Monarch Biosphere Reserve, the area in central Mexico where millions of migrating butterflies spend the winter, has led to deforestation that exposes monarchs to wind and cold temperatures, leading to their death.

In a statement about the impact of deforestation on monarch populations, Chip Taylor, professor of ecology and evolutionary biology at the University of Kansas, said, “It’s so truly spectacular, one of the most awe-inspiring phenomena that nature presents to us. There is no way to describe the sight of 25 million monarchs per acre — or the sensation of standing in a snowstorm of orange as the butterflies cascade off the fir trees. To lose something like this migration is to diminish all of us.”

Patches of pollinator habitat aren’t just important for migrating butterflies; the plantings also provide places to feed and nest for the species that stick closer to home. Stitching together a patchwork of habitats was one of the goals of creating the North Carolina Butterfly Highway.

With the bells from the light-rail crossing ringing in the background, Angel Hjarding, director of pollinator and wildlife habitat programs for the North Carolina Wildlife Federation, dressed in a gauzy butterfly- printed scarf, points out the pollinator plants at First Ward Park in downtown Charlotte, North Carolina. When the Charlotte-Mecklenburg Parks and Recreation Department established the four-acre park on the site of a former parking lot, the raised beds were filled with traditional landscape plants like fescue grass (Festuca), Bermuda grass (Cynodon dactylon) and bush clover (Lespedeza bicolor) that, while popular, provided no value to pollinators. “The commercial landscape industry never stops to ask, ‘Who’s eating this?’ We need to start thinking about how we address the needs of pollinators in urban areas, and habitat is one important option,” explains Hjarding.

In 2017, Hjarding suggested using grant funds to replace 3,000 square feet of “useless” plants in First Ward Park with alternatives such as milkweed and mountain mint (Pycnanthemum muticum) that provide nectar and habitat for butterflies and other pollinators. The pilot project turned into a flagship public site on the North Carolina Butterfly Highway.

Now, walking along the paved path between raised beds and the great lawn as traffic whizzes past, Hjarding explains the need for the collection of pollinator habitats that make up the Butterfly Highway: Charlotte added more than 15,000 residents in 2016, making it one of the fastest-growing cities in the nation, and development has kept pace. In June 2017, more than 2,000 new residential units were under construction in the downtown area alone. Exploding development means less pollinator habitat and longer distances between available habitats.

By planting “pollinator patches” in Charlotte — and throughout North Carolina — Hjarding hoped to provide a network for fragile populations to congregate. She recruited fifty households in five neighborhoods to kick-start the North Carolina Butterfly Highway in 2015. The project has grown to include 1,700 patches of habitat at parks, government buildings, community centers, and residential yards. (Around the same time when Hjarding launched the North Carolina Butterfly Highway, former Charlotte mayor Jennifer Roberts signed the Mayor’s Monarch Pledge, creating a new landscape ordinance that required at least 50 percent of all new trees, shrubs, and ground cover planted as part of city projects in Charlotte to be native plants.)