Evaluation method of biological nitrogen removal capacity in water based on functional traits of benthic animals

A method for evaluating nitrogen bio-removal capacity in water based on functional traits of benthic macroinvertebrates, wherein the method comprises following steps:

• S1, constructing an evaluation table for the nitrogen bio-removal capacity in water based on final functional trait evaluation scores of benthic macroinvertebrates, wherein the evaluation table for the nitrogen bio-removal capacity in water is divided into multiple grades, and said grades are classified according to different ranges of the final functional trait evaluation scores of benthic macroinvertebrates,
• S2, collecting the benthic macroinvertebrates in the water to be evaluated, calculating the final functional trait evaluation scores of the benthic macroinvertebrates in the water to be evaluated based on modalities that are strongly correlated with nitrogen bio-removal rate of water indicating the nitrogen bio-removal capacity in water, and then determining corresponding grade of the nitrogen bio-removal capacity in the water to be evaluated from the evaluation table pre-constructed for the nitrogen bio-removal capacity in water according to obtained final functional trait evaluation scores of benthic macroinvertebrates, the step of constructing an evaluation table for the nitrogen bio-removal capacity in water based on final scores obtained from the evaluation of functional traits of benthic macroinvertebrates comprises:
• S11, collecting benthic macroinvertebrate samples at multiple sampling sites, and for each sampling site, constructing a benthic macroinvertebrate abundance matrix based on species and individual counts of collected benthic macroinvertebrates,
• S12, constructing a benthic macroinvertebrate functional trait matrix comprising multiple functional traits of benthic macroinvertebrates,
• S13, for each sampling site, performing a logarithmic transformation on the constructed benthic macroinvertebrate abundance matrix, and multiplying it by the constructed benthic macroinvertebrate functional trait matrix to obtain a modality value matrix representing the modalities in the functional traits of benthic macroinvertebrates, wherein a parameter for j-th modality of i-th functional trait of benthic macroinvertebrate is denoted as benthic macroinvertebrate modality parameter Aij,
• S14, for each sampling site, obtaining nitrogen bio-removal rate of the water based on on-site measurement;
• and based on the obtained measured nitrogen bio-removal rates, screening out the strongly correlated traits and strongly correlated modalities among the benthic macroinvertebrates that are strongly correlated with nitrogen bio-removal rate of the water,
• S15, based on the obtained measured nitrogen bio-removal rates of water, combining with partial least squares regression, calculating and determining first component value for the strongly correlated modalities,
• S16, based on the screened strongly correlated modalities, and taking the corresponding first component value of the strongly correlated modalities as modality weight Bi, calculating final functional trait evaluation scores of benthic macroinvertebrates for each sampling site according to formula X=ΣAij·Bi,
• S17, performing a statistical distribution analysis on the final functional trait evaluation scores of benthic macroinvertebrates across all sampling points, and grading the nitrogen bio-removal capacity in the water based on the quantile intervals where the scores fall, so as to obtain the final evaluation table for the nitrogen bio-removal capacity in water.