Grazing and right-of-way affect native rangeland 12 years after pipeline construction in southern Alberta

Abstract

ABSTRACT Over the past 100 years, large areas of native grasslands have been lost due to human activities and natural disturbances. Construction of pipelines for oil and gas transportation continues to pose significant challenges to grassland ecosystems. Thus, reclamation of disturbed native grasslands is critical for their existence in North America and around the world. This study investigated long-term (12 years) effects of grazing and right-of-way (RoW) treatments on revegetation of native rangeland on two pipelines in southeastern Alberta, Canada. Grazing and RoW treatments influenced soil and vegetation parameters; and plant species group responded differently at Milo and Porcupine Hills. Grazing was associated with significantly greater bare ground and decreased litter at both sites and increased vegetation cover at Porcupine Hills. At Milo grass density and biovolume increased as RoW disturbance increased, but not at Porcupine Hills. Trenching increased rhizomatous grasses and all RoW disturbances reduced tufted grasses. Vegetation was dissimilar on the RoW from undisturbed prairie with intermediate levels of disturbance (work, storage) having greater plant species diversity, whereas grazing had no effect. This study suggests 12 years may not be long enough for restoration of native rangelands after pipeline construction although there was some progress.