Characteristics and historical changes in the fish community structure in Longyangxia Reservoir
To quantify the fish assemblage and its historical change,we conducted surveys in Longyangxia Reservoir in May,September,and December 2023 and analyzes the data against historical data. Nineteen species of fish were collected,belonging to 4 orders,6 families,and 15 genera,among which Cyprinidae was the dominant family,accounting for 52.63％ of the total species captured. The dominant species of fish in Longyangxia Reservoir were Carassius auratus,Oncorhynchus mykiss,Triplophysa scleroptera,Pseudorasbora parva,Hypomesus olidus,and Gymnocypris eckloni,and the dominant species of fish in the main stream of the Yellow River were Gymnocypris eckloni,Schizopygopsis pylzovi,and Gymnodiptychus pachycheilus. The species diversity index was highest in May and lower in September and December. ABC curve analysis showed that the W value was greater than 0,the biomass dominance curve was above the abundance dominance curve,and the community structure of Longyangxia Reservoir was relatively stable. Comparative analysis with data from 1981 and 2005-2007 showed that,since the impoundment of Longyangxia Reservoir,indigenous fish decreased by two species and exotic fish increased by 10 species. Currently,Longyangxia Reservoir is dominated by fishes that prefer quiet and slow water,are omnivorous,lower-middle,sedentary,exhibit sticky egg-laying,and the lower mouth. The ecological matrix of individual fish showed that the indigenous fish in Longyangxia Reservoir were mainly in the lower middle layer (R=0.556) and the lower mouth (R=0.889),which provided ecological niche vacancies for broadly adapted exotic fishes. The fish composition of Longyangxia Reservoir in 2023 showed a similarity index of 0.33 (moderately dissimilar) with that of 1981,and a similarity index of 0.50 (moderately dissimilar) with that of 2005-2007. The fish community structure changed significantly after the impoundment of Longyangxia Reservoir in 1987. The analysis confirmed that the reservoir impoundment and the introduction of exotic fishes were the main reasons for the changes in the fish community structure of the Longyangxia Reservoir.
fish assemblagehistorical changeexotic fishecological typeLongyangxia Reservoir
万方数据
维普
