Fish Functional Groups Of Structure And Seasonal Changes In Taizi River Benxi Site

Under certain habitat conditions,fish communities will changed with day,night,seasons and year.Fish interacts with the surrounding environments and other organisms.While affecting the habitats of rivers,the spatial heterogeneity and cyclical time dynamics of rivers also affect the distribution of fish and changes in community structure.Changes in the water environment will directly affect the survival and reproduction of fish,which in turn will change the community structure and diversity of fish on different spatial and temporal scales.Exploring differences in fish community structure is an important issue in the study of species ecology.This study takes the Benxi section of the Taizi River Basin as the research background,and collects 18 sampling sites in the Benxi River in the Taizi River basin in spring(April),summer(August),and autumn(November)in 2017.The aquatic organisms,mainly fishes,were studied.Based on the hydration environment and feed resources of the Benxi section of the Taizi River Basin,the Shannon diversity index,species richness,and evenness index of fish,phytoplankton,benthic,and aquatic insect communities were analyzed.Through principal component analysis,Pearson correlation analysis,and canonical correspondence analysis,the main environmental factors that mainly affect the aquatic bio-community structure were selected.Through differential analysis of multi-response displacement analysis(MRPP),the differences in fish community structure and fish functional groups in different seasons were explored,and the main reasons for this difference were found.The main findings are as follows:(1)One-way analysis of variance for the water environment factors in the Benxi section of the Taizi River Basin shows that the water temperature T,pH value,and total phosphorus content in the four seasons of April,August,and November in the Benxi section of the Taizi River Basin The ammonia nitrogen content NH4+ and chemical oxygen demand COD showed significant differences.Canonical correspondence analysis results showed that in April the chemical oxygen demand COD,water temperature T,pH value,conductivity Cond,and total phosphorus content TP had a significant correlation with the fish community structure.In August,the water temperature T and biochemical oxygen demand(BOD)of the hydration factor had a significant correlation with fish community structure.In November,the conductivity had a significant correlation with fish community structure.The results of studies on fish structure in the Benxi section of the Taizi River Basin indicate that the environmental factors affecting fish community structure are different in different seasons,and the fish community structure also shows different differences in different seasons.The results of multi-response permutation analysis show that the fish community structure in the Benxi section of the Taizi River Basin has obvious spatial heterogeneity(P<0.001).In the Benxi section of the Taizi River Basin,23 species of fish were collected in the spring,belonging to 5 orders and 6 families.In summer,21 species of fish were collected,belonging to 4 orders and 6 families.In the autumn,17 species of fish were collected.5 heads and 6 divisions.The average value of the Shannon-Wiener index in spring was 2.27,the average value of the average index was 0.72,the average value of the Shannon-Wiener index in summer was 2.26,the average value of the evenness index was 0.39,and the average value of the Shannon-Wiener in autumn was 1.94.The average value of the average index is 0.32.(2)The Benxi section of the Taizi River Basin as a whole is dominated by omnivorous functional groups,middle-lower functional groups,stone functional groups,and viscous egg functional groups.In April,fish-eating,mid-lower functional groups,nest-laying and spawning functional groups,and sand-habiting functional groups dominated;in August,herbivorous functional groups,low-level functional groups,and viscous egg functional groups dominated,and in November,The omnivorous functional group,the upper and middle functional groups,the special spawning functional group and the heavy egg functional group are the main ones.According to the canonical correspondence analysis between functional groups of the fish community and habitats in the Benxi section of the Taizi River Basin,the results show that the influencing factor on the distribution of insect predatory functional groups is dissolved oxygen(DO)(P<0.05),affecting sensitive functional groups and tolerance The impact factors of the functional distribution of the smut are total phosphorus content TP and dissolved oxygen content DO.Biochemical oxygen demand BOD and dissolved oxygen content DO are the influencing factors affecting the distribution of middle and lower functional groups,and the main environment affecting the distribution of sticky egg functional groups.The factor is dissolved oxygen content DO(P<0.05).(3)The richness of the bait in the water will directly affect the development and total amount of fish resources.The biomass and spatio-temporal distribution of various diets will,to some extent,cause differences in the distribution of fish resources.A sampling survey of phytoplankton in April,August and November in the Benxi section of the Taizi River Basin resulted in the following findings: A total of 70 species of algae were identified in April and the average species density was 460.45 cells/L.8 A total of 6 species of 99 algae were identified in the month,and the average species density was 8748.9 cells/L.In November,72 species of algae were identified,of which 6 were in total.The average species density was 6877.924 cells/L.MRPP results showed that the heterogeneity of phytoplankton in the different seasons under the Benxi section of the Taizi River Basin was significantly different(P<0.0001).Through the investigation of zoobenthos and aquatic insects in the Benxi section of the Taizi River in April,August and November,38 species of benthic and aquatic insects were collected in April,belonging to 3 families,6 orders,12 orders,23 families and 23 genera.The average density of density distribution was 298.76/L.A total of 34 species of benthic and aquatic insects were collected in August,belonging to 3 genera,4 classes,8 orders,14 families and 18 genera.The average density of species density was 449.02/L.A total of 26 species of aquatic insects and benthic animals were identified and collected in November,belonging to 17 families and 17 families in 3 orders,5 classes,8 orders,and the average density of species density was 142.9/L.MRPP results showed that the heterogeneity of macrobenthos and aquatic insects in the different seasons under the Benxi section of the Taizi River Basin was significantly different(P<0.0001).