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Environmental changes and the dynamic response of biological community along the shore of Lake Biwa

琵琶湖沿岸环境变化与生物群落动态响应

基本信息

批准号：
07458120
负责人：
YUMA Masahide
金额：
$ 4.86万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07458120/
关键词：
Lake Biwa environmental changes eutrophication biological community indigenous species exotic species

项目摘要

There are about 70 species of fishes in the present Lake Biwa. They include fishes which have been speciated in the lake by expanding their habitat into deep and open offshore of the lake, and also the exotic species like the largemouth bass the bluegill. There are also about 50 species of molluscs, a half of them are endemic to the lake.Many of these fishes and molluscs, however, utilize the shallow shore of the lake and inland waters through or during a part of their life. The survey on the historical changes in human activities along the lake shore revealed ; the most areas along lake shore and inland waters had been developed into paddy fields from old ages, however, the environment of these area has been changed again within this two or three decades. Such environmental changes might cause the changes in biological community in shallow waters along lake shore, inland waters and paddy fields. The land development far from the lake mightalso affect on the freshwater biological community around lake shore, especially on the fishes migrating between rivers and the lake.On the other hand, the underwater direct observation with the aid of SCUBA on the community structure of benthic animals along the lake shore revealed that many benthic animals depends on not only the lake bottom structure but also the condition of aquatic vegetation though the most of aquatic vegetation is occupied by exotic species. In another case, the decrease in lake water level causes the separation of fish population into riverine and lacstrine populations by blocking their upstream migration, though the water level of Lake Biwa is basically depends on the weather condition but also largely by human management.

现在的琵琶湖大约有70种鱼类。它们包括通过将栖息地扩大到湖的深水和开阔的近海而在湖里形成物种的鱼类，也包括像大口黑鱼这样的外来物种。还有大约50种软体动物，其中一半是湖特有的。然而，这些鱼类和软体动物中的许多在生命的一部分中利用湖泊的浅岸和内陆水域。对湖滨人类活动历史变迁的考察表明，湖岸和内陆水域的大部分地区自古以来就被开发成水田，但在这二三十年里，这些地区的环境又发生了变化。这种环境变化可能会引起湖岸浅水、内陆水域和稻田生物群落的变化。远离湖岸的陆地开发也可能对湖岸周围的淡水生物群落产生影响，特别是对江湖之间的鱼类的影响。另一方面，借助水下呼吸器对湖岸底栖动物群落结构的水下直接观察发现，许多底栖动物不仅取决于湖底结构，还取决于水生植被的状况，尽管大部分水生植被都被外来物种占据。在另一种情况下，湖泊水位的下降阻止了鱼类的上游迁徙，导致鱼类种群分离为河流种群和湖泊种群，尽管琵琶湖的水位基本上取决于天气条件，但也在很大程度上取决于人为管理。