Prairie Plant Species At Risk In Southern Alberta: Identification Of Critical Habitat At The Microsite Level For Halimolobos virgata (Nutt.) O.E. Schulz And Determination Of Set Back Distance Between Pipeline Disturbance And Halimolobos virgata And Crypta

Little is known about the effect disturbances such as pipelines can have on prairie plant species at risk and their critical habitat in Alberta. Halimolobos virgata appears to be a ruderal, disturbance evolved species that occupies a unique rim niche. This habitat around the rim of depressional areas is slightly compacted with high bare ground, low litter, lower surrounding vegetation height and slightly different soil chemical properties compared to random, typical prairie environments. A pipeline changes the environment up to 25 m from the pipeline right of way edge with increases in soil compaction, bare ground and non native plant species richness and decreases in litter cover. This distance is recommended as a set back for Cryptantha minima. Halimolobos virgata can recolonize a pipeline right of way under certain pipeline construction conditions, thus a set back distance is not required provided construction is under these specified conditions.