十年禁渔初期金沙江干流鱼类群落结构及物种多样性OA北大核心CSTPCD

Based on catch survey data from six stations(Gangtuo,Benzilan,Shigu,Panzhihua,Qiaojia,and Suijiang)in the Jinsha River main stream from May 2022 to November 2023,we analyzed the current status of the composition of the fish community,characteristics of the dominant species,spatial and temporal distribution of the diversity of the community,and proposed conservation measures for fish in the Jinsha River main stream.The study collected a total of 68 fish species,distributed across 4 orders,15 families,and 48 genera.Cypriniformes were the most abundant(51 species),accounting for 75.0％of the total species count.Among these,5 species were nationally protected fishes,while 7 were exotic.The ecological types of the collected fish mainly included omnivorous,benthic,and sedentary fishes,representing 66.18％,44.12％,and 72.06％,respectively.The dominant species within the community were Hypophthalmichthys molitrix,Coptodon zillii,and Schizothorax dolichonema.Various diversity indices were calculated:the Shannon-Wiener diversity index(H'),Simpson diversity index(D'),Peilou evenness index(J'),and Margalef richness index(R').These indices ranged from 1.376 to 2.012,0.646 to 0.816,0.574 to 0.797,and 1.149 to 2.870,respectively.ANOVA analysis revealed the temporal variations in the four diversity indices were not significant(P＞0.05).However,spatial differences were observed to be significant(P＜0.05).ABC curve analysis showed that the biomass curve was above the abundance curve,and the W statistic value was positive,indicating that the community was less perturbed,but there were some changes in fish species and ecotypes compared with the historical records.The genera and family diversity indices(G-F)in 2022-2023 decreased from 0.29 to 0.19,but the number of species relatively increased;the results of cluster analysis and NMDS ordination analysis showed that the fish communities in the mainstem Jinsha River section were divided into 2 groups:Gangtuo,Benzilan,and Shigu in one group;and Qiaojia,Panzhihua,and Suijiang as the other.The similarity percentage(SIMPER)analysis showed that the species composition of the fish communities varied significantly among different seasons,and the main divergent species were Hemiculter tchangi and Rhodeus sinensis.As a systematic survey conducted after the fishing ban,the present results served as a benchmark for evaluating the ban's effectiveness on the Yangtze River.Based on these results,it is recommended to enhance the management of the fishing ban,monitor the population dynamics of exotic species,and impplement habitat restoration efforts in both the main stream and tributary streams to safeguard the fish diversity of the Jinsha River.