Concentration, mass, and distribution of nutrients in a subarctic Piceamariana – Cladoniaalpestris ecosystem

Abstract

The concentration and mass of nutrient elements (N, P, K, Ca, Mg, Cu, Fe, Mn, Na, Zn) were examined in 110-year-old lichen woodland in the subarctic of eastern Canada. Biomass plus soil organic matter contained two-fifths (41%) of the total nutrient mass in the system. Calcium (85%), P (76%), Mg (67%), and K (64%) were largely in live biomass. Nitrogen was equally in biomass plus organic soil (45%) and mineral soil (55%). Micronutrients were mainly in the soil inorganic fraction. Nitrogen was acutely deficient for rapid growth. Potential loss of Ca under logging and burning regimes consistently exceeded exchangeable soil reserves. A realistic evaluation of these impacts was dependent on more complete knowledge of net atmospheric and soil inputs and vegetation requirements. Dominant tree, shrub, and lichen genera all differed strongly in the concentration of tissue elements. Among vascular species, total element concentration related inversely to species abundance. Since evergreen perennial plants of low nutrient concentration prevailed at maturity, we postulated that nutrients increasingly limited the abundance of deciduous shrubs.