Species Diversity And Conservation Of Fish And Benthic Fauna In Upper Reaches Of The Jinsha River

This paper conducted a systematic survey of the main 12 water bodies in the study area in September 2019 and June 2020 respectively,and analyzed fish and benthic animals species composition,diversity status,spatial distribution of communities,and the main environmental factors affecting the community.Constructed the Fish Integrity Index(FIBI)and Benthic Integrity Index(B-IBI)to evaluate the aquatic ecological health of the study area,and use the Maxent model to predict the upper reaches of the Jinsha River for indigenous fish and invasive fish,and then assessment of threats to aquatic organisms in the study area.The main findings are as follows:1.There are 44 species of fish(including 2 subspecies)distributed in upper reaches of Jinsha River,belonging to 3 orders,9 families and 25 genera.Among them,there are a total of 33 species of indigenous fishes,including 22 species(66.67%)of Schizothoracinae and Triplophysa,4 species belongs to a national second class protected,7 provincial protected fishes,9 endangered fishes,and 6 vulnerable fishes There are 30 species endemic to China,27 species endemic to upper reaches of the Yangtze River,and 12 species endemic to Jinsha River.A total of 1,432 fishes were collected in the autumn survey,belonging to 3 orders,5 families and 15 genera.In the summer survey,a total of 810 fishes were collected,belonging to 3 orders,6 families and 12 genera,Schizothorax wangchiachii and Gymnocypris potanini firmispinatus and Schizopygopsis malacanthus are dominant species.The average values of H',D,J' in autumn are 1.46,0.77,0.73,and the average values of H',D,and J' in summer are 1.20,0.84,0.63.The seasonal variation of diversity is not significant,and the spatial values are higher than left and right.At the bottom,the north is high and the south is low.Based on Cluster and NMDS analysis,the fish in the study area can be divided into 4 communities in autumn and 5 communities in summer.The main environmental factors affecting the spatial distribution of fish communities are water temperature,altitude and pH.2.A total of 93 species of benthic animals were identified in this survey,belonging to 5 phyla,5 classes,10 orders,42 families,88 genera.76 species(86.36%)of Arthropoda,7 species(7.95%)of Mollusca,and Annelid are 4 species(4.55%),only one species(1.14%)of Platyhelminthes and Nematoda.In the autumn survey,40 species of benthonic animal were collected,belonging to 3 phyla,5 classes,12 orders and 28 families.The dominant are Baetis sp.,Heptagenia sp.and Hydropsyche sp.,the dominance is 20.29%,5.35% and 2.34% respectively,the average density is 257.8ind./m~2,and the average biomass is 3.08g/m~2.A total of 69 species of zoic animals were collected in the summer survey,belonging to 5 phyla and 7 classes 14 orders and 35 families,the highest dominance is Baetis sp.,Ephemera sp.and Cinygmina sp.,the dominance is 8.23%,7.14%,7.14% respectively,the average density is 308 ind./m~2,and the average biomass is 3.04g/m~2.The average values of H',D,and J' in autumn are 2.52,2.39,and 0.71,and the average values of H',D,and J' in summer are 2.72,3.57,and 0.74.The seasonal variation of diversity is not significant.Based on Cluster and NMDS analysis,the benthic fauna in the study area can be divided into 5 communities in autumn and 4 communities in summer.The main environmental factors affecting the spatial distribution of benthic communities are water temperature and dissolved oxygen.3.Fish and benthic animals were selected as indicator organisms to construct a biological integrity assessment system for the ecological health of rivers in upper reaches of the Jinsha River.Reference points and damage points were selected through the ? diversity coefficient and onsite investigations.Index distribution range test,sensitivity analysis and correlation test.From 23 F-IBI candidate indicators,the total number of fish species,the total number of exotic fish species,the number of species of Schizothoracinae,the number of species of Noemacheilidae,ShannonWiener diversity index,percentage of individual carnivorous fish,percentage of pelagic fish species,percentage of demersal fish species,percentage of sinking egg fish species,and viscous egg fish species,the percentage of fish species with special spawning types,the percentage of loach individuals in the total,the percentage of endemic species in the total,and the percentage of endangered and vulnerable species.A total of 14 indicators were constructed for F-IBI.The results showed that 72.73% of the water body is above sub-healthy,and 27.27% of the water body is in an unhealthy state.From the 33 B-IBI candidate indicators,the total taxa,the number of Plecoptera,the relative abundance of the top 3 dominant taxa,the relative abundance of the Plecoptera,the relative abundance of Trichoptera,the relative abundance of Coleoptera,the relative abundance of pollution-tolerant groups,the FBI index,the relative abundance of collectors,the relative abundance of predators,and the Simpson diversity index total 11 indicators were selected to construct B-IBI,and the results show that 82.61% water area is above sub-health,and 17.39% are in an unhealthy state.4.Based on the Maxent model,using our laboratory's records of fish collection in upper reaches of Jinsha River in the past ten years and 20 environmental variables downloaded by WorldClim,we have made a prediction of the suitable habitat for the aboriginal fish and invasive fish in upper reaches of Jinsha River.The results show that the main stream of Jinsha River and the upper and middle water bodies of the Shuiluo River and Dingqu River are the best habitats for indigenous fish in the region,The southern part of the region is the best habitat for invasive fish.The assessment of river threat factors shows that the operation of hydropower stations,the presence or absence of towns,invasion of alien species,and tourism development are the main threat factors to water bodies in the upper reaches of Jinsha River.