Dominance of Picea glehnii in the Serpentine Forests of Hokkaido: Perspectives for an Ecological Understanding

Picea glehnii dominates serpentine forests in Hokkaido, whereas Abies sachalinensis dominates forests on brown soils. The main corresponding hypothesis in the literature is that P. glehnii is better adapted to harsh serpentine soils, but this has only been partly investigated. Here, we report preliminary results on aboveground and fine‐root functional traits related to adaptation to harsh substrates, measured for both species on both kinds of sites, together with observations of regeneration microsites. First, we tested the hypothesis that P. glehnii is better adapted to serpentine soils based on comparisons of functional trait values. P. glehnii showed more conservative leaf traits than A. sachalinensis , consistent with adaptation to infertile serpentine soils. However, its greater height does not match the expected size reduction on serpentine and may instead indicate efficient growth on this substrate. Second, we consider other nonexclusive hypotheses from the literature. Both P. glehnii functional traits and observations of its regeneration on fallen logs support adaptation to soil disturbance, which is expected to be more frequent in serpentine areas. In addition, its benefit from disturbance may be related to release from negative biotic interactions, including plant–soil pathogens and competition with the abundant dwarf bamboo found on serpentine. Finally, three priorities for future research are proposed: (i) large‐scale characterization of P. glehnii distribution, focusing on climatic and edaphic factors and regeneration microsites; (ii) identification of the plant–soil feedbacks controlling regeneration in both species; and (iii) analysis of the interaction between dwarf bamboo competition and tree canopy cover in controlling seedling development.