Exact Growth and Increased Nitrogen Compensation by the Arctic Sedge Carex aquatilis var. stans after Simulated Grazing

Abstract

We investigated the effect of clipping on a natural stand of Carex aquatilis var. stans in Sverdrup Pass (79°N), Ellesmere Island. We clipped plants up to four times each growing season for 4 yr to a height of 1.5 cm above the moss canopy to simulate natural grazing. Cumulative biomass production above 1.5 cm showed exact compensation of lost tissue after clipping and cumulative nitrogen accumulation above 1.5 cm increased significantly in the frequently clipped plots. The concentration of nitrogen in rhizomes did not decrease in heavily clipped plots, even at the end of four seasons of clipping. Nitrogen losses from plants as a result of clipping were apparently overcompensated by increased uptake of nitrogen. We concluded that the plants had the capacity to compensate for the loss of clipped tissue by producing new growth.