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Influence of forest decrease and land-use development on fishery resources in coastal lake region

森林减少和土地利用开发对滨湖区渔业资源的影响

基本信息

批准号：
15580132
负责人：
YANAI Seiji
金额：
$ 2.37万
依托单位：
Hokkaido Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15580132/
关键词：
Suspended sediment land-use lake forest GIS Stable isotope Abashiri Fisheries resources 地質

项目摘要

The dynamics of suspended sediment concentration and the impact on a lake-inhabiting bivalve were studied in the Abashiri River basin, in eastern Hokkaido. The Japanese corbicula (bivalve : Corbicula japonica) is the most important fisheries resource in Abashiri Lake, which has an area of 32.3 km^2 and a mean depth of 6.1 m. Eighteen water-collection stations were established based on different land-use and geological conditions. The water was collected from spring to summer during freshet. The amounts of forest cover and agricultural land, as well as the slope gradient, lithological hardness, and the number of faults in each tributary were also calculated using Geographic Information Systems. Sediment concentrations greater than 1600 mg/l were observed at all stations along the main channel in the summer of 2003, except at the uppermost station and the station downstream from the lake. Suspended sediment (SS) concentrations >1600 mg/l were also measured in the tributaries. The factors influencing SS concentration were analyzed by multiple regression analysis. This led to the identification of soft bedrock and fault as significant factors influencing sediment concentration. Fine-sediment particles less than 10 μm in diameter accounted for more than 50% of the samples at all stations. Since the lake bivalve prefers coarse substrates, a negative relationship was observed between the amount of fine sediment. The substrate around the mouth of the river was also composed of fine sediment, which indicated that it had been transported from an upstream tributary. Together, the data show that the suspended sediment produced from the mountain tributaries has deteriorated the lake environment, especially for corbicula survival and growth. Careful watershed management, such as monitoring the effect of forestry and land-use practices, is required to protect the fisheries resources.

研究了北海道东部阿巴什里河流域悬沙浓度的动态变化及其对湖栖双壳类的影响。Abashiri湖面积32.3 km2，平均水深6.1m，是当地最重要的渔业资源，根据不同的土地利用和地质条件，建立了18个集水站。这些水是在春季至夏季期间收集的。利用地理信息系统计算了各支流的森林覆盖量、耕地面积、坡度、岩性硬度和断层数量。2003年夏季，除最高站和下游站外，主航道沿线各站含沙量均大于1600 mg/L。还测量了支流悬沙浓度&GT；1600 mg/L。对影响SS浓度的因素进行多元回归分析。这导致软基岩和断层被认为是影响含沙量的重要因素。直径小于10μm的细颗粒沉积物占各站样品的50%以上。由于湖泊双壳类喜欢粗糙的底质，因此细粒沉积物的数量与之呈负相关。河口周围的底质也由细小的沉积物组成，这表明它是从上游的一条支流运来的。综合数据显示，山区支流产生的悬浮泥沙使湖泊环境恶化，尤其是对河口的生存和生长。为了保护渔业资源，需要进行仔细的流域管理，例如监测林业和土地利用做法的影响。