1994 Fiscal Year Final Research Report Summary
STRUCTURE AND FUNCTION OF RIPARIAN ZONE AND IMPLICATIONS FOR JAPANESE RIVER MANAGEMENT
| Project/Area Number |
05660152
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
林学
|
|---|
| Research Institution | Hokkaido University |
|---|
Principal Investigator |
NAKAMURA Futoshi HOKKAIDO UNIV., FAC.OF AGR., ASSOCIATE PROF., 農学部, 助教授 (90172436)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KIKUCHI Shun-ichi HOKKAIDO UNIV., FAC.OF AGR., INSTRUCTOR, 農学部, 助手 (10250490)
YAJIMA Takashi HOKKAIDO UNIV., FAC.OF AGR., ASSOCIATE PROF., 農学部, 助教授 (90142702)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Keywords | Riparian zone / Riparian forest structure / Ecological function / Shading / Litter falling / Coarse woody debris / River environment / flood control |
|---|
| Research Abstract |
This report describes the ecological structure and function of riparian zone which vary with spatial scale. The riparian zone consists of valley floor landform and riparian vegetation. The functions discussed are attenuation of sunlight energy, input of leaves and needles, contribution of woody debris to streams, and retention of flowing material out of transport. These primary functions directly or indirectly influence water and sediment qualities of streams, bars and floodplains. Shading provided by tree crowns over the stream strongly influences water temperature and primary production in lotic ecosystems. Litter falling into streams is a critical food resource for stream organisms, especially in forested headwater streams. Coarse woody debris supplied from hillslopes and floodplains create storage sites for organic and inorganic matters and enhance habitat diversity for aquatic biota. Moreover, stems and roots of riparian vegetation comb inorganic and organic matter transported from upstream, increasing the soil nutrients of floodplain deposits. Variation in valley floor width plays an important role in retaining materials transported in stream water by increaxing hydraulic and geomorphic complesity. Generally, these functions diminish with an increase in watershed area although some functions are kept in floodplains of large rivers. The main reason for this longitudinal variation is due to changes in the relative size of riparian trees and the stream channel. The new river management policy should emphasize the ecological functions of the riparian zone. Finally, the authors proposes river restoration planning by preserving or creating landscape elements based on the concepts of sustaining physical and ecological linkages.
|
