| Water shortage has become the focus of attention in a worldwide range and the pollution of fountainhead is getting more serious in China. By studying the-species composition of bio-system, the distribution of vegetation and the reservoir water quality ,we investigated the biological resources in the Changtan Reservoir area ,which is the fountainhead of Taizhou City.The analysis of the biological species, sampled from the Changtan Reservoir area, shows that: (1) there were 70 species of algae in the reservoir, belonging to 9 phyla. Among these species, the Chromulina sphaerica, Ochromonasand sp. and Chlamydomonas sp. appeared seasonally, the former two present in spring and autumn, the latter present in Summer, all of these three species can be used as indicator species because they were resistant to pollution. The presence of the Chroomonas acuta, Cryptomonas ovata, Euglena gracilis, and Colacium was one of the symbols of eutrophication. The Microcystis, Chroococcus and Coelosphaerium can form a large colonies and they were dominant component of cyanobacteria water bloom. Cyanobacteria were the dominant group of phytoplankton and their maximal average density reached 22.89x104 cell/ L, and the diatoms and the green algae reached 1.6x104 cell/ L and 3.06x104 cell/ L, respectively. The miniaturization of planktonic algae and the presence of cyanobacteria are symbols of the eutrophication. (2) There were 113 species of aquatic vascular plants, belonging to 74 genera in the investigated area. Amongthese species, 5 species belonging to 4 genera were ferns, and the rest 108 species (including 45 new recorded species and 17 exotic species) belonging to 70 genera were seed plants. The aquatic vascular plants in this area were abundant, but their biomass was very small. They were mainly distributed in small ponds, ditch, bottomland and streams. According to the components of the aquatic life forms and the kinds of pioneering species, the aquatic plants in Changtan Reservoir area could be divided into 4 vegetation formations (including 28 associations): emergent, floating-leaved, free-floating and erect form. Among these formations, the erect life-form and the emergent life-form species were dominant. Because of the difference in each form of the associations and the environment where they were living, these species show different functions in purifying water quality. (3) The vegetation including coniferous forest, coniferous and broadleaf mixed forest, evergreen broadleaf forest, deciduous and evergreen broadleaf mixed forest, bamboo forest, shrubs and grass mixture. These could be divided into four vegetation-type groups, 8 vegetation types, 12 vegetation formations, and 19 association groups. Around Changtan Reservoir, the vegetation was mainly coniferous and fruit trees. In order to recover the vegetation in the reservoir area, the natural forest should be enlarged, and the fruit trees proportion should be cut down. (4) There are 23 genera of zooplankton (including 42 species), belonging to the Protozoa Phylum, the Nematoda Phylum and the Arthropod Phylum. Among these species, Sarcodina had the highest number, including 22 species; the second is Rotifer, including 10 species; there were 6 species of Cladocera and 4 species of Copepoda. With the deterioration of eutrophication, the zooplankton population structure will become simpler, the number of small zooplankton and zoobenthos of the reservior will increase, species that are sensitive to organic pollution will decrease or disappear completely, while species that can tolerate pollution will be more and more numerous, Sarcodina (Protozoa) and Rotifera (Nematoda) were the species that can tolerate pollution, Diaphanosoma brachyurum and Daphnia carinata as well, can be used as indicators of water pollution. (5) Benthicanimals of the reservoir included annelid, mollusk and arthropod and there were 22 species in total. Among these species, annelid had 5 species belonging to 2 families; Mollusk had 11 species belonging to 7 families; Arthropod...
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