Assessing the Impact of Anthropic Pressures on Aquatic Macroinvertebrates: A Functional Trait Approach in the Irtysh River Watershed.

Simple Summary: This study investigates the evolutionary dynamics of macroinvertebrate functional traits within the Irtysh River Basin under the influence of urbanization. Through comprehensive field assessments and data analysis, we document a significant transition process toward pollution-tolerant functional characteristics in macroinvertebrates, coinciding with the rapid pace of urban development. Simultaneously, the community undergoes a gradual transition, marked by an increase in pollution-tolerant taxa. Urbanization-induced environmental pollution and waste discharge emerge as prominent catalysts, accelerating the observed changes in macroinvertebrate communities and functional traits. Our findings underscore the critical role of anthropogenic factors in aquatic ecosystems and highlight the imperative of strategic management strategies to mitigate these effects. This study contributes to a deeper understanding of the intricate interplay among urbanization, environmental change, and benthic organism responses, providing essential insights for sustainable river management amidst urban expansion. Little is known about how changes in the biodiversity and functional traits of macroinvertebrates in rivers respond to the responses of anthropic pressures and their driving factors. Macroinvertebrates were sampled at 17 sites in the Irtysh River Basin and classified macroinvertebrates into 10 traits and 38 categories between May and August 2022. Then, we performed R-mode linked to Q-mode (RLQ) analysis and calculated functional richness, evenness, divergence, and Rao's quadratic entropy (RaoQ) for each site and community-weighted means for each trait category. Our results indicated that there were pronounced alterations in species variability in the urban region. Functional divergence indicated fierce competition among species and considerable niche overlap in the urban region. Functional evenness indicated that species abundance distribution and interspecific functional distance were not uniform in the urban region. Functional richness indicated that the urban region was the strongest region in terms of niche occupation, resource utilization, and buffering capacity for environmental fluctuations. Rao's quadratic entropy showed that the trait difference of macroinvertebrates was the largest in all regions, which was caused by the gradient environmental difference. Research has revealed that urbanization significantly influences the evolutionary trajectory of macroinvertebrate fauna, culminating in an upsurge in pollution-tolerant species and a convergence of functional traits. We recommend strengthening the control of urban and industrial pollution and wise planning and management of land and water resources to mitigate the impact of anthropogenic destruction on habitat fragmentation in the Irtysh River Basin. [ABSTRACT FROM AUTHOR]