Temporal And Spatial Changes Of Functional Groups Characteristics Of Benthic Macroinvertebrates In Qixinghe Nature Reserve

This study collected benthic macroinvertebrates in Spring(May),Summer(July)and Autumn(September)2017 from 12 sample sites in Qixinghe Nature Reserve,the spatial and temporal distribution of species,density and biomass were analyzed,and it identified two functional groups,comprehensive evaluated the water quality by using the physical and chemical indicators,biological indicators and biological indexes.The main results of this study are as follows:The samples of benthic macroinvertebrates collected for 14 orders,32 families and 66 species,which can be classified into four categories:mollusc,annelid,aquatic insect and shellfish,respectively belonging to Mollusca,Annelida and Arthropoda.There were 42 species of aquatic insects,accounting for 63.64%of the total species.In addition,12 species of molluscs and 11 species of annelids were found,and only 1 species of shellfish was found.The dominant species of each season were mostly Gastropoda,such as Bithynia fuchsiana in spring,Cipangopaludina ussuriensis in summer and Radix ovata in autumn.The density and biomass of benthic macroinvertebrates are related to their species composition.The annual density of benthic macroinvertebrates was between 11ind/m2 and 1155ind/m2.The annual biomass of benthic macroinvertebrates was between 0.08g/m2 and 371.38g/m2.The feeding functional group of benthic macroinvertebrates was dominated by predators with 28 species.There were 12 kinds of gathers collectors and 10 kinds of scrapers.The highest density of the year was the scrapers,up to 5379ind/m2.In the movement functional group of benthic macroinvertebrates,the number of species of clingers,burrowers and sprawlers were more,which were 17,16 and 14,respectively.The annual density of clingers was much higher than that of other groups,as high as 7128ind/m2.There was little difference among the distribution of functional groups of benthic macroinvertebrates in Qixinghe Nature Reserve.In terms of species and density,predators,scratchers and direct predators were relatively important groups in the feeding functional groups,and adherents,diggers and crawlers were relatively dominant groups in the movement functional groups.In addition,the dominant feeding functional groups in each season and functional area were predators,and the dominant motor funnctional groups were adherents.The composition of sediment and type of aquatic vascular plants are important environmental factors affecting the community structure of benthic macroinvertebrates.This study found that the more content in the sediment,the richer aquatic vascular plant types,the richer the species of benthic macroinvertebrates,and the more functional groups.The functional groups in the humus-rich samples(e.g.7#)were significantly more than those without humus(e.g.1#),and the functional groups in the vegetative rich and diverse samples(e.g.5#)were more than those in the vegetative single and sparse samples(e.g.2#).Contrast national surface water quality standard,the physical and chemical indicators showed water quality evaluation was I class water,there was little difference from spatial and temporal distribution.Total nitrogen content and water quality standard,indicated that water from Qixinghe Nature Reserve was slightly polluted.This study used indicators for water quality monitoring,which mainly belongs to clean species fotnd ephemeroptera(e.g.Caenis sinensis)and odonata(e.g.Brachythemis contaminata),but their distribution were not common;Oligochaetes(e.g.Limnodrilus claparedeianus)and larva(e.g.Polypedilum pedestrians)were found among the pollution-resistant species,and there were many types but few distribution.The water quality of the comprehensive indicator was close to that of clean water,but it did not have the conditions for mass breeding of clean indicator species.This study selected five biological indexes for analysis.Each index focused on different directions,and the results were slightly different.The Simpson index and Pielou index evaluation results were all clean water.Shannon-wiener index and index BPI were light pollution.The Margalef index shows that water quality tends to be moderately.Overall,the water quality of Qixinghe Nature Reserve was slightly polluted.