Interactions between tall oatgrass invasion and soil nitrogen cycling

• Published in: Oecologia Vol. 199; no. 2; pp. 419 - 426
• Main Authors: Hinckley, Eve-Lyn S., Miller, Hannah R., Lezberg, Ann, Anacker, Brian
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2022; Springer; Springer Nature B.V
• Subjects: aboveground biomass; Ammonium; Ammonium compounds; anthropogenic activities; Anthropogenic changes; Anthropogenic factors; Arrhenatherum elatius; autumn; Biomedical and Life Sciences; Biosphere; Colorado; Cycles; Ecological function; Ecology; Ecosystem Ecology–Original Research; Ecosystems; Flowers & plants; Foothills; Grasslands; Hydrology/Water Resources; Indigenous plants; Indigenous species; introduced plants; Introduced species; Invasive plants; Invasive species; Life Sciences; Metropolitan areas; Mineralization; Moisture effects; Mountain ecology; Mountains; Nitrogen; Nitrogen cycle; Plant Sciences; Plant species; Seasons; Soil; Soil moisture; soil water; Statistical analysis; summer; tall oatgrass; Woodlands; Colorado; Nitrogen mineralization; Plant-soil interactions; Species diversity; Biogeochemistry; Restoration; Nitrification; Tallgrass prairie; Invasion ecology
• ISSN: 0029-8549; 1432-1939; 1432-1939
• DOI: 10.1007/s00442-022-05192-x

Increases in nitrogen (N) inputs to the biosphere can exacerbate the introduction and spread of invasive non-native plant species. Often, with elevated soil N levels, invasive plants establish and further enrich soil N pools, changing overall ecosystem function. This study examined the relationship between soil N cycling and an increasingly prevalent, invasive plant species, tall oatgrass ( Arrhenatherum elatius subsp. elatius ), in foothills ecosystems between the Colorado Rocky Mountains and the Denver-Boulder Metropolitan area—similar to many Western US grasslands and woodlands. It focused on investigating differences in soil N transformations, inorganic N pools, and vegetation characteristics across invaded and uninvaded plots at three sites in two seasons (summer and autumn). There was a statistically significant effect of invasion on rates of net N mineralization, but it was dependent on site and season ( p  = 0.046). Site had a statistically significant effect on soil moisture and aboveground biomass C:N ( p  < 0.04). The interactions of invasion x site were statistically significant for ammonium pools ( p  < 0.03). These findings suggest that A. elatius invasion can be associated with accelerated N cycling, but that the nature of the relationship differs by location and season in the foothills. More broadly, this study contributes to determining how the N cycle is shifting in grassland ecosystems subject to increasing pressures from anthropogenic change.