The ubiquitous sight of power lines through both rural and urban areas creates an obvious corridor for the eye to see. Like most corridors, however, power lines have the potential to support the dispersal of both native and non-native species, due in part to the frequent disturbance with which they are managed. Although most research has shown that the potential negative effects of corridors do not outweigh the potential positive impacts, there is still the possibility of power lines creating habitat that ultimately benefits aliens. New research in Finland from Lampinen et al. looks at the extent of native grassland species versus alien species in power line cuts, and pinpoints which characteristics of power lines are most likely to affect the presence of each.
Over 400 plant species were recorded in 71 plots, including 150 grassland and grassland indicator species and 94 alien species. Grassland and alien species favored corridors with slightly different characteristics: grassland species were more abundant in corridors with dry, steep slopes, and a land cover history of pastures, while alien species were more abundant in corridors surrounded by a dense urban fabric, with abundant light and productive soils. Both grassland and alien species composition were most influenced by light and, particularly, soil conditions.
The implication is that including power line corridors in grassland conservation decisions has the potential to expand and support habitat for native species. Native grassland species will be most successful in old, dry corridors with steep slopes and a history of use as pastures. The most active conservation practices for deterring the spread of alien species are needed in recently clear cut corridors on productive soils that are close to the urban fabric. Incorporating these considerations into the management of power lines can make the difference in preventing further spread of non-native species.
Lampinen, J., K. Ruokolainen, and A.-P. Huhta. 2015. Urban power line corridors as novel habitats for grassland and alien plant species in south-western Finland. PLOS ONE. DOI: 10.1371/journal.pone.014223.