Differential growth patterns and fitness may explain contrasted performances of the invasive Prunus serotina in its exotic range

Abstract

This research investigates why the invasive American black cherry tends to dominate the forest canopy on well-drained, nutrient-poor soils, but usually hardly establishes on both waterlogged and calcareous soils in its exotic range. Prunus serotina was sampled from four soil types and two light conditions, to measure (1) radial growth; (2) height growth compared to the main native competitor, Fagus sylvatica; (3) leaf traits; (4) seed production; and (5) rate of fungal attack. We found that P. serotina invested a significant amount of energy in height growth and seed production on well-drained, nutrient-poor soils. These characteristics enabled it to rapidly capture canopy gaps and subsequently exert a mass effect on neighbouring stands. On moist soils, we found irregular growth patterns and high rates of fungal attack, while on calcareous soils, leaf traits suggested a low nitrogen assimilation rate, limiting the production of N-containing compounds. We conclude that P. serotina fails on waterlogged and calcareous soils because it is unable to allocate sufficient energy to fruiting and/or height growth. Conversely, it succeeds on well-drained, nutrient-poor soils because of high fitness which increases its invasiveness.