Abstract:

By combining the classical faunal analysis method and the value of faunal presence method, we analyzed fish diversities and their representatives in three first level tributaries including Nangunhe, Nantinghe and Mengboluohe in Yunnan to the middle Salween River system, to compare the difference in values of fish faunal presence and to analyze the characteristics of the faunal composition and the importance of families and genera in fauna formation. The purpose of the study was to explore the guiding role of the fish faunal presence value index in planning and establishing fish nature reserves. Results showed that a total of 74 endemic species were recorded in middle Salween River system in the Yunnan section, belonging to 5 orders, 12 families, and 45 genera. 53 species were recorded in these three first level tributaries, belonging to 5 orders, 12 families, and 38 genera, among them 32 species belonging to 9 families and 23 genera in Nangunhe; 47 species belonging to 11 families and 33 genera in Nantinghe; and 33 species belonging to 10 families and 26 genera in Mengboluohe. Sorted by species absolute number, Cyprinidae, Cobitidae and Sisoridae were ranked in the top 3 families in the three first level tributaries. Sorted by the fauna presence value, Anguillidae, Channidae, Mastacembelidae, Cobitidae, Synbranchidae and Sisoridae were ranked in the top 5 families in the three first level tributaries. Results from the two methods were consistent with one another. The faunal presence value in the same genus changed greatly in the different tributaries, and the regional distribution features of the genus and species became obviously. The fish composition in the three first level tributaries was composed of a primitive group from the Palaeogene, comprised of a group that originated from the south and a small number of taxa that originated from Qinghai Tibet Plateau. The results of the fish fauna presence values indicated that one or more of the first level tributaries should be selected as reserves in the upper, middle and lower reaches of the main stream when setting up freshwater fish natural reserves. The greater the taxa of orders and families with a high fauna presence value covered when planning fish natural reserves, the greater the protection, which was not an element must be considered. However, the fauna presence value of the genera should be a special concern when planning reserves.

Key words: fish fauna, faunal presence value, biodiversity, fish nature reserve, Salween River system