Nutrient cycling strategies.

This paper briefly reviews pathways by which plants can influence the nutrient cycle, and thereby the nutrient supply of themselves and of their competitors. Higher or lower internal nutrient use efficiency positively feeds back into the nutrient cycle, and helps to increase or decrease soil fertility. These tendencies are further enhanced by secondary effects (higher or lower rates of decomposition of litter and hence of nutrient mineralization) in resp. fertile and infertile soils. Such feedbacks may strongly increase the fitness of the plants involved. Plants can also influence the external inputs and outputs into the plant-soil system, by affecting the general hydrology of their environment. Sphagnum peat bogs exemplify an extreme degree of control of plants over the hydrological cycle, causing intense nutrient impoverishment by making the ecosystem dependent on nutrient supply from the atmosphere, apparently giving Sphagnum a competitive edge over other plants.