Do power line rights-of-way facilitate the spread of non-peatland and invasive plants in bogs and fens?

Abstract

Linear infrastructures are known to facilitate the spread of undesirable species in ecosystems. Compared with other types of infrastructure, the role of power line rights-of-way (ROWs) as dispersal vectors remains poorly understood, especially with regard to peatlands. The aim of our study was to evaluate their impacts on the vegetation of ombrotrophic (bog) and minerotrophic (fen) peatlands. The vegetation communities within and adjacent to power line ROWs were sampled in 23 bogs and 11 fens in southern Québec. In fens, invasive species were found in abundance along the first 250 m within ROWs, while native non-peatland species were able to spread into entire ROWs. Invasive species were also able to colonize the adjacent fen habitats but were mostly concentrated in the first 4 m from ROW edges. Some species were, however, able to establish at more than 43 m from ROWs. Invasive and native non-peatland species were mostly restricted to the first 31 m within ROWs intersecting a bog and almost none dispersed in the adjacent bog habitats. Overall, the average cover of native non-peatland and invasive species in ROWs was mostly related to intrinsic abiotic conditions such as water pH, water conductivity, and water table level, while landscape surrounding the peatland and historical variables (e.g., time elapse since the construction of the ROW) had few impacts in both bogs and fens.