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Browsing by Author "Wilkinson, Sarah R."

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    Influence of pipelines and environmental factors on the endangered plant, Halimolobos virgata (Nutt.) O.E. Schultz over a 10 year period
    (2020) Naeth, Anne M.; Locky, David; Wilkinson, Sarah R.; Bryks, Candace L.; Low, Caitlin H.; Nannt, Meghan R.
    We investigated the effects of pipeline construction and environmental factors on the occurrence and characteristics of the endangered plant Halimolobos virgata (Nutt.) O.E. Schultz. The plants were surveyed from 2007 to 2016 at three sites along the Keystone Pipeline in southern Alberta, Canada. Plant height, number of flowers and siliques, as well as microhabitat and climate data were collected up to 300 m away from the pipeline. Pipeline construction and distance had no effect on plant numbers or physical characteristics, with occurrences increasing markedly over time. Greater litter cover and depth and spring precipitation were associated with plant height and number of flowers and siliques. Vegetation cover was negatively correlated with H. virgata cover; however, plant height and number of flowers and seed pods were positively influenced by graminoid cover. The highest occurrences of H. virgata coincided with the driest and wettest years, and higher winter and spring temperatures. Some of this pattern can be attributed to the plant’s annual, biennial, and short perennial life forms, which may overlap and create a temporary exponential growth rate for an annual plant under ideal conditions. This research highlights the importance of understanding a species’ life history for the development of effective conservation and recovery strategies.
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    Pipeline impacts and recovery of dry mixed-grass prairie soil and plant communities
    (2020) Naeth, Anne M.; Locky, David; Wilkinson, Sarah R.; Nannt, Meghan R.; Bryks, Candace L.; Low, Caitlin H.
    Agricultural practices have historically dominated disturbance on North American grasslands. Disturbances from oil and gas have become increasingly common and problematic for grassland conservation. With growing demand for oil and gas, industry is actively implementing minimal disturbance techniques during construction to reduce impacts on grasslands. This study aimed to determine impacts of a large-diameter pipeline right of way (ROW) on dry mixed-grass prairie to determine if and how far these impacts extended beyond the ROW and the effect of time on grassland recovery on and off ROW. Soil and vegetation on the ROW and on transects extending 300 m on either side of the ROW were assessed over a 10-yr period, starting the yr of construction, at six sites along a pipeline route in southern Alberta, Canada. There were significant impacts to soil and vegetation on the ROW and within 5 m of the ROW in the first yr. The trench was most impacted, followed by work and storage areas. Within 2 yr, soil and plant communities were on a trajectory toward reference prairie conditions. Ten yr following construction, only soil pH and bare ground were greater, and litter was less, on the trench than on work and storage areas, and relative to reference prairie. While native grass richness, dominance, and cover were similar on and off ROW, abundance of some native forb species was less on ROW. Non-native species cover was < 2% in all yr and locations. Although ruderal weed species were abundant on ROW the yr following construction, they disappeared by the following yr. Use of minimal-disturbance construction techniques reduced the size and intensity of the disturbance footprint, allowing for even sensitive arid habitat to recover within a short period of time. Similar approaches to other grassland disturbances can increase ecosystem resiliency.