美工圖片   Investigation of Current Status in Zeng-Wun River System (Water Resources Planning Institute, WRA, MOEA. April, 2006)

The purposes of the two-year plan are to integrate ecological information and current status on the ZengWun River System in order to provide a basis of ecological engineering planning and an establishment of ecological resources database. In addition to the compilation of abiotic factors (physical conditions, water quality indices, engineering constructions, and recreation usages), we conducted seasonal biological surveys on algae, aquatic insects, shrimps, crabs and freshwater fishes in aquatic ecosystem , and on riparian vegetations, mammals, birds, reptiles, amphibians, and butterflies in terrestrial ecosystem.

The contents of the river situation investigation include: (a) the river physical survey (including the river essentials, watershed essentials, flow and water quality, river type...etc.);(b) the biological survey (including fish, shrimps, crabs, spiral shells, shells, aquatic insects, algae, birds, mammals, reptiles, amphibians, butterfly, dragonfly, plant, etc.);(c) the river usage condition (including riparian land utilization condition, river usage condition...etc.) ; (d) the ecosystem resources data base establishment.
 

ZengWun River
 

This plan has finished ecological survey in main stream of ZengWun River System from June 2004 to January 2006. It was conducted seasonal biological surveys in aquatic ecosystem on fish, shrimps, crabs, spiral shells, shells, aquatic insects, and algae, and in terrestrial ecosystem on birds, mammals, reptiles, amphibians, butterflies, dragonflies, and terrestrial plants. The acquisition data of this region contains 11 fixed positions and 26 random positions totally.

In the aquatic ecosystem, it recorded 11 orders, 36 families, and 80 species of fish; 11 families and 29 species of shrimps and crabs; 2 class, 12 families, and 17 species of spiral shells and shells; 7 orders and 19 families of aquatic insects; 5 phyla, 65 genera, and 106 species of algae. There are 10 endemic species and only one conservation species of fish. There are also 17 exotic species of fish.

In the terrestrial ecosystem, there are 17 orders, 53 families, and 163 species of birds; 7 orders, 14 families, and 30 species of mammals; 2 orders, 10 families, and 30 species of reptiles; 5 families, and 23 species of amphibians; 8 families, and 87 species of butterflies; 7 families, and 19 species of dragonflies. The birds amount to 6 first–rate preservation species, 24 second–rate preservation species, 14 third– rate preservation species, 8 endemic species, and 46 endemic subspecies. The mammals amount to 4 endemic species, 13 endemic subspecies, and 4 second–rate preservation species. The reptiles amount to 4 endemic species, and 10 second–rate preservation species. The frogs amount to 5 endemic species, and 7 second–rate preservation species.
 

In general, most of the species are typical animals that represent the ecological status in this region. Some species (i.e., birds) showed a seasonal abundance pattern due to the migration, while most of the species maintained a fairly constant population size. It is worth paying attention to the serious invasion of the exotic fish (17 species) and exotic birds (7 species), and this will impact native species directly or indirectly.

The resource database based on GIS technology was compiled. In the database, various layers of abiotic and biotic factors were digitized. These maps included administration, topography, river,

ZengWun Reservoir

ZengWun River Dike

 

 

Mashan Bridge

human development, water survey, pollution index and biological resources. A web-based query system was also established and installed. Users may access the maps from remote computers.

Our work on the current status in the ZengWun River System is only a beginning for effective management of the natural resources in the region. We expect similar work can be conducted in other rivers of Taiwan in the near future, and these data can be compiled in a well-designed database. These status reviews should provide a starting point for our river management work and, thus, a better environment for future generations.