Roads can also affect aquatic ecosystems because streams are often channelized or rerouted, and wetlands are often partially drained. While the ecological effects of roads are mostly negative, it doesn't have to be this way. Awareness of the extent of roadside effects can help people meet both transportation and conservation goals, says Forman. For instance, people can restore roadsides with native plants, providing habitat for butterflies, birds and other animals. Many roads in agricultural areas of Australia are bordered by nature reserves.
People can also find ways to help animals cross roads safely.
Fourteen European countries are collaborating to build wildlife underpasses, overpasses and tunnels in an effort to reconnect habitat that has been fragmented by roads. Forman's work is part of a special section of the February issue of Conservation Biology on the ecological effects of roads, which was edited by Marion Hourdequin of the University of Montana in Missoula. Hourdequin adds that people should also avoid building new roads, particularly in rural and roadless areas. They are reducing the abundance of forest mammals virtually everywhere. Wright and his colleagues reasoned that poachers are probably also affecting forest plants, in part because many of the seeds are dispersed by mammals.