Phenology and resource allocation in a high arctic evergreen dwarf shrub, Cassiope tetragona

During the growing season of 1981, we studied phenological patterns of development of vegetative shoots and sexual organs, partitioning of biomass and productivity, and partitioning and concentrations of N, P, K, Ca, and Mg for the evergreen dwarf shrub Cassiope tetragona (Ericaceae) at a high arctic lowland oasis at 79°N on Ellesmere Island, Canada. Short elongation (3.6 mm yr⁻¹) and net production (5% of aboveground phytomass) of Cassiope were small. Vegetative and reproductive development were initialed just after snowmelt. Seasonal patterns of allocation of phytomass and nutrients to current growth were characterized by gradual accumulation of quantity over the growing season. However, concentrations of N, P, and K decreased by ca 50% in current tissues during the growing season, while Ca increased with tissue age. Overwinter storage of nutrients occurred in live aboveground shoots. The large proportion of phytomass that occurred as aboveground, attached dead material, as well as the small net production and belowground standing crop, suggest an allocation pattern more similar to that of high arctic cushion plants, than to other evergreen, ericaceous dwarf shrubs occurring at lower latitudes in the Arctic.