Halophyte Resilience to Roadside Salinity in Urban Southeastern Michigan

Abstract

For the past 70 years, municipalities in southeastern Michigan have used chloride as a deicer in winter months. This has resulted in increasing soil salinity and halophytes (salt tolerant plants) proliferating along roadsides. Three halophytes that have taken root in Michigan are common mugwort (Artemisia vulgaris), Bassia scoparia, and seaside goldenrod (Solidago sempervirens) were studied along with Canada goldenrod (Solidago canadensis) as a control. Roadside soil was collected to measure its sodium content, texture, moisture content, organic matter content, and pH. The sodium content of the halophytes stems, roots leaves, secondary stems, fruits, and flowers were also measured. Results have demonstrated all three species have adapted to saline environments as includer halophytes. The perennials seaside goldenrod and common mugwort were found to have contained more sodium than the annual Bassia scoparia. Sequestered sodium was highest in the leaves and stem of the seaside goldenrod, the secondary stems of common mugwort, and the fruit or leaves of Bassia scoparia. Soil sodium content was highest at soil by highways and lowest in residential areas. Additionally, salinity is affected by moisture content and soil texture. Lastly, the sodium content of plants increases with soil salinity. Halophyte sodium content was highest in those collected from roadsides while halophytes growing in soil with no to little salt contain no or little sodium as well. Common mugwort was found growing in soil with the highest salinity measured, seaside goldenrod the second most, and Bassia scoparia the least.