Root dynamics of Carex stricta-dominated tussock meadows
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- Lawrence, B.A., Fahey, T.J. & Zedler, J.B. Plant Soil (2013) 364: 325. doi:10.1007/s11104-012-1360-y
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Background and aims
The roots of tussock-forming plants contribute to the formation of microtopographic features in many ecosystems, but the dynamics of such roots are poorly understood. We examined the spatial heterogeneity of tussock fine root dynamics to investigate allocation patterns and the role of root productivity in the persistence of tussock structures.
We compared the spatial variability of fine root (<1 mm, 1–2 mm) density, biomass, % live, allocation, turnover rate (using bomb 14C), and productivity of four Carex stricta Lam.-dominated tussock meadows in the upper Midwest, USA (3 reference, 1 restored site).
Relative to underlying microsites, tussocks were warm, dry, and high in root density, productivity, % live biomass, and turnover. Root productivity averaged 649 g m−2 yr−1 (±208) in reference sites, comprised 57 % (±10) of total net production, and was concentrated in tussocks (70 % ± 4). Root turnover rate averaged 0.63 yr−1 (±0.08), but tussocks had ~50 % faster root turnover than the underlying soil, and <1 mm roots turned over ~40 % faster than 1–2 mm roots.
Our detailed analysis of the spatial heterogeneity of tussock root dynamics suggests that high allocation and elevated turnover of tussock roots facilitates organic matter accumulation and tussock persistence over time.