Alder Distribution and Expansion Across a Tundra Hillslope: Implications for Local N Cycling.

ABSTRACT: Increases in the availability of nitrogen (N) may have consequences for plant growth and nutrient cycling in N-limited tundra plant communities. We investigated the impact alder (Alnus viridis spp. fruticosa), an N-fixing deciduous shrub, has on tundra N cycling at a hillslope located on Alaska's Seward Peninsula. We quantified N fixation using ¹⁵N₂ incubations within two distinct alder communities at this site: alder shrublands located on well-drained, rocky outcroppings in the uplands and alder savannas located in water tracks along the moist toeslope of the hill. Annual N fixation rates in alder shrublands were 1.95 ± 0.68 g N m^-2 year^-1, leading to elevated N levels in adjacent soils and plants. Alder savannas had lower N fixati

SUBMITTER: Salmon VG 

PROVIDER: S-EPMC6807776 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature