关键词: 饲草作物, 根冠比, 粗蛋白产量, 水分利用效率, 间作群体

Abstract: Fishes in Yunnan Jianhu Lake are important food sources for many migratory birds. Changes in fish species composition have significant impacts on structure and function of wetland ecosystems. In this study, we investigated fishes in Jianhu Lake to understand the composition of fish community and the homogenization of fish fauna between Jianhu Lake and its related areas. A total of 24 fish species were historically recorded in Jianhu Lake, including nine indigenous species and 15 alien species. 20 species still existed, and four indigenous species were functionally extinct. Eight alien species were recorded for the first time. It was confirmed that the endangered species Schizothorax yunnanensis was still distributed. Among all the alien species, 11 species were from the middle and lower reaches of the Yangtze River, accounting for 73.3% of the total; and 13 species originated from China, accounting for 86.7%. The genus and family diversity index (G-F) was 0.45 in the original indigenous community, but the current value was only 0.26, indicating that the fish community differentiation in the lake has changed from complex to simple with the invasion of exotic fish. The fish fauna similarity between Jianhu Lake and several adjacent plateau lakes has obviously increased. Moreover, the similarity of species composition between Jianhu Lake and main lakes in the middle and lower reaches of the Yangtze River has reached a significant level (P=0.05). The fish fauna in Jianhu Lake has evolved into one dominated by the main component of the river plain. Results from the individual ecology matrix analysis showed that the habitat requirements were similar between alien species and indigenous species, with strong competition.

Key words: intercropping system, water use efficiency, forage crop, root/shoot, crude protein yield