MULTIDIMENSIONAL DIVERSITY OF FRESHWATER BENTHIC MACROINVERTEBRATE UNDER MULTIPLE ENVIRONMENTAL STRESSORS

To investigate the impacts of common stressors, including climate warming, water body eutrophication, and pesticide pollution, on the diversity of freshwater benthic macroinvertebrates, this study simulated a freshwater ecosystem under multiple environmental stressors using a mesocosm system. The diversity and correlation among different diversity indices of benthic macroinvertebrates were analyzed at different stages of continuous pulse and restoration. Results showed that warming significantly increased species diversity and functional richness index (FRic) of benthic macroinvertebrate (<italic>P</italic>&lt;0.01); however, this positive effect disappeared with prolonged warming. Nutrient loading exerted no direct significant effect on diversity but had a positive lasting effect on the average taxonomic distinctness index (Delta+) (<italic>P</italic>&lt;0.05). The insecticide (imidacloprid) pulse mainly affected functional diversity, with a negative effect at the early pulse stage (<italic>P</italic>&lt;0.05), followed by a positive effect at the continuous pulse stage (<italic>P</italic>&lt;0.01), though no long-term effects were observed at the late recovery stage. The combined effects of the three stressors resulted in lasting declines in key functional diversity indices (<italic>P</italic>&lt;0.05). Correlation analysis showed significant positive relationship between species diversity and functional diversity (<italic>P</italic>&lt;0.05). Partial indices of phylogenetic diversity and functional diversity also exhibited significant correlations at different experimental stages (<italic>P</italic>&lt;0.05). The correlation strength of functional diversity indices gradually increased with the progress of the experiment. These findings highlight that long-term warming exacerbates the negative impacts of anthropogenic stressors on freshwater ecosystem functions. Functional diversity demonstrated higher responsiveness to environmental stressors, whereas phylogenetic diversity better reflected community recovery from pulse stressors. This suggests that evaluating artificial interventions in freshwater ecosystems requires integrating multidimensional diversity assessments to enhance accuracy and reliability. In summary, this study reveals the dynamic responses of multidimensional diversity in freshwater benthic macroinvertebrates under multiple environmental stressors, providing new insights for comprehensive diversity assessments under long-term environmental stressors.