Making a Beeline Through Portland

by Heather McCargo

Habitat Corridors for Pollinating Insects

Bees and butterflies are getting a lot of attention these days, now that they are in severe decline. Our whole ecosystem depends on declining populations of bees, butterflies, and other pollinators. Pollinators transfer pollen between flowers, resulting in fertilization and the combining of genes, which ensures the genetic diversity that is crucial for the long-term survival of a species.

Without bees, butterflies, and other pollinators need more than just flowers: they require places to nest, reproduce, and overwinter. That's where we come in: we can build corridors of supportive environments in our communities for migrating insects and birds to help protect and preserve our environment.

What pollinators want
Bees and butterflies are most active in warm weather when they forage for nectar and pollen, but this is just one part of their life cycle. During the larval stage, they need the foliage or stems of specific native plants to reproduce and feed (the monarch butterfly’s dependence on milkweed is a classic example). Many of our native species rely on green foliage, woody stems, and leaf litter for year-round food and habitat.

Most common ornamental plants fail to provide our native pollinators with the habitat they need. Ornamental plants have been bred for characteristics that are appealing to people, not bees or butterflies. Many multi-petalled double flowers have no pollen, nectar, or ovaries — they don’t attract pollinators or produce seeds. Herbs and most agricultural crops, on the other hand, produce seeds or fruit and rely on pollinators to reproduce.

Humans have altered the natural landscape and reduced pollinating insects’ ability to survive, but we can bring their habitat back. Creating corridors of native plants stretching across the landscape, from healthy wild habitats through farmland and into our most populated urban areas, provides native pollinators pathways for foraging, nesting, and migrating.

Creating pollinator habitat in Portland

What would a habitat corridor look like? Most people can’t imagine a city or suburban area populated with native plants. Our Portland Pollinator Vision Plan, created in collaboration with graduate students from the Conway School of Landscape Design, illustrates what a thriving, urban ecosystem could look like in this place.

Even in Maine’s most densely-built and populated city, there’s still space for native plants and pollinators. The Portland Pollinator Vision Plan is a design manual and tool kit for returning native plants to the city. The plan emphasizes the creation of habitat corridors that support the insects and birds that are crucial to a healthy ecosystem and agricultural production. This will help species migrate across the landscape that connects the metropolitan area with the surrounding countryside.

In the city of Portland, native plant species can thrive anywhere there is bare dirt, lawn, waste areas, or weeds. Wet drainage areas, dry gravelly soil, mown strips, and roadside edges can all be made more beautiful with the addition of native plants that will invite the pollinators back and keep the native habitat in balance.