长江上游宜宾至合江江段鱼类群落结构及优势种分析OA

To evaluate the initial response of fish communities to the"Ten-Year Fishing Ban"in the National Na-ture Reserve for Rare and Endemic Fish in the Upper Yangtze River(Yibin-Hejiang section),a survey was conducted across four mainstream reaches(Yibin,Jiang'an,Jiangyang,and Hejiang)in 2024.We analyzed fish species composi-tion,ecological types,dominance patterns,and community stability to assess post-ban ecological changes.A total of 5 809 individuals representing 84 species,59 genera,18 families,and 4 orders were collected.Notable captures included 5 nationally key-protected wildlife species,namely Acipenser dabryanus,Myxocyprinus asiaticus,Coreius guichenoti,Pro-cypris rabaudi,and Leptobotia elongata,along with 23 Yangtze-endemic fish species and 9 alien fish species.The fish community was characterized primarily by demersal,omnivorous,and rheophilic fishes.Dominant species(IRI>1000)were identified as Acipenser dabryanus,Coreius heterodon,and Pelteobagrus vachellii.Community-level diversity indi-ces were:Shannon-Wiener=3.38,Simpson dominance=0.95,Margalef richness=9.59,and Pielou evenness=0.76.Abundance-biomass comparison(ABC)curve analysis indicated that the fish community structures in all surveyed sections were in a state of moderate disturbance.Comparative analysis with pre-ban historical data revealed early signs of recovery:the richness of rare and endemic species increased,and the dominance structure shifted from small-bodied spe-cies to a complex assemblage involving medium-and large-sized fish.However,the community structure generally re-mained in a transitional adjustment phase.These findings provide essential baseline data for monitoring the long-term eco-logical trajectories of fish communities under the fishing ban.