Iowa has the highest density of roads and among the greatest habitat loss of any state--less than 0.001% of the native prairie is left. New research shows that restoring prairie along roadsides increases the number of butterfly species that live there.
This research was presented by Leslie Ries at the June 1999 Society for Conservation Biology meeting.
Ries and her colleagues compared the abundance and diversity of butterflies in three types of roadside vegetation: grass (which contains primarily non-native grasses), weeds (which contains primarily non-native plants, some of which are butterfly hosts) and restored prairie (which includes butterfly host plants such as prairie clover and compass plant).
The results showed that restoring prairie along roadsides increases the diversity of rare butterflies: compared to grass and weeds, roadside prairie had twice as many species of butterflies that are sensitive to habitat disturbance.
The results also showed that roadside prairie may provide corridors or stepping stones between patches of butterfly habitat. Compared to butterflies in roadside grass, butterflies in prairie are only half as likely to cross the road.
Restoring prairie along roads has a huge potential for conservation: Iowa alone has more than 600,000 acres of roadside vegetation and there are millions more nationwide. "Wildlife benefits are not the primary goal of roadside vegetation but they could be," says Ries. "We need to explore this more, for example we don't include butterfly host plants on purpose but we should."