Evaluation of ecological restoration using a simplified construction method of topsoil block transplantation for slope revegetation

Abstract

We developed a simplified topsoil block transplantation method to mitigate the impacts of the construction of National Route 40 on the surrounding old-growth boreal mixed-forest ecosystem of the Nakagawa Experimental Forest of Hokkaido University. Herbaceous vegetation and soil animal communities were compared between topsoil block transplantation treatments and transplantation without a blocked soil structure (controls). In the conventional method, equipment dedicated for soil blocks is used, but in our simplified method, commonly used construction machinery is used whenever possible. As a result, construction costs are dramatically reduced. The simplified soil block transplantation method developed in this study contributed to early recovery of plant and soil animal communities. Compared to control plots, block transplantation promoted higher species richness of herbaceous vegetation, composed of more native perennial herbs and woody plants and fewer exotic biennial plants. The similarity in plant communities between transplanted and source sites was greater in topsoil block plots than in control plots. The numbers of individuals and species of soil animals were also higher in topsoil block plots than in control plots. The similarity in soil animal communities between transplanted and source sites was greater in topsoil block plots compared to control plots.