Functional response of plant communities to clearcutting: management impacts differ between forest vegetation zones

摘要

Understanding of the ecological impacts of logging practices on biodiversity and associated ecosystem processes is essential for developing sustainable forest management approaches. We documented the impacts of clearcutting on the functional structure of tree and herbaceous communities in hemiboreal, cool-temperate, warm-temperate and subtropical forests in the Japanese archipelago and identified forest vegetation that is vulnerable to deterioration of important ecosystem functions. We combined species data for leaf, stem, flower and fruit traits related to productivity, nutrient cycling and habitat quality for wildlife with phytosociological vegetation data from unmanaged and previously clearcut forests, then calculated functional structure indices [community mean (CM) of trait values, functional richness (FRic) and functional divergence (RaoQ)] of plant communities. For tree species, functional structure indices of specific leaf area (SLA), leaf carbon and nitrogen concentrations, maximum height, wood density and flower size differed between unmanaged and clearcut forests, while for herb species, only maximum height differed between the two forest types. Functional structure indices showed divergent patterns across forest vegetation zones. In hemiboreal, cool-temperate and warm-temperate forests, the CMs of SLA and leaf nitrogen concentration were greater and that of leaf carbon concentration was smaller in clearcut than in unmanaged forests. Although clearcut forests had greater species richness than unmanaged forests, FRic and/or RaoQ of maximum height were smaller in clearcut forests. In hemiboreal and cool-temperate forests, FRic and RaoQ of SLA were also smaller in clearcut forests. In contrast, subtropical forests showed no differences in species richness and functional structures between unmanaged and clearcut forests.Synthesis and applications. Functional redundancy of plant communities differs among traits and among forest vegetation zones. After intensive logging, hemiboreal, cool-temperate and warm-temperate forests were more vulnerable to the loss of ecosystem functions related to leaf and stem traits of tree species than were subtropical forests, which appeared relatively resilient. Locally adaptive management to maintain multiple ecosystem functions should be developed based on the degree of functional complementarity among plant species in forest communities.