環境

学術研究成果リスト

Detail of Grant Awarded Academic Researches

Project

Regenerated vegetation and stand conditions in denuded area by destruction of alien invasive species forests in the middle reach of the Tama-gawa River.

Academic
Research
No.330
Principal
Investigator
Mikiyo Wada
Affiliation
(at that time)
Kumamoto University School of Pharmacy Department of Medicinal Plant Research Associate Professor
Research
Summary

In the middle reach of the Tama-gawa River, on the right bank of floodplain between Yotuya-Honsyuku Ground sill and the confluence of the Tama-gawa River and the Asa-kawa River, forests of alien invasive species such as Robinia pseudoacacia (originally come from North America) or Ailanthus altissima (originally come from China) were destructed as a part of natural restoration project on the gravel riverbed vegetation. In the barren area emerged by grubbing trees, we monitored regenerating vegetation for 4 years. We also investigated relief features, sediment deposit and soil moisture to clarify relationship between regenerating vegetation and environmental factors. Some plants typical of gravel riverbed vegetation, such as Chamaecrista nomame, Potentilla chinensis, and Artemisia capillaris were colonization in the area with fine sediment and relatively high soil moisture, whereas Lespedeza striata and L. stipulacea were recruited in the area with coarse sediment and relatively low soil moisture. R. pseudoacacia and Ailanthus altissima regenerated by sprouting from roots that were remained in the ground after tree grubbing, and they showed quick‐growing in the area where soil moisture condition was relatively high. The coverage of gravel riverbed vegetation decreased with the increase of coverage of the alien tree species and Pueraria montana var. lobate, indicating that extermination of these alien trees and climber are necessary to establish gravel riverbed vegetation.


Collaborators

Fusako Nagaoka

Shigetoshi Okuda


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