Multidimensional biodiversity and macroinvertebrate community structure response to seasonal changes in hydrology in southwest China karst region

Understanding the response of macroinvertebrate communities and diversity to seasonal hydrological changes is crucial for maintaining biodiversity, ecosystem functioning, and services. This study was a systematic examination of the seasonal dynamics of aquatic environments, macroinvertebrate multidimensional diversity, and community structure across three hydrological seasons (normal, dry, and wet) in a karst stream in southwest China. The dry season exhibited the highest taxonomic richness (16.7 ± 11.1) but lower taxonomic–phylogenetic diversity (222, median), alongside minimal evenness (0.65 ± 0.19). The wet season had higher richness (11.6 ± 7.6), the greatest phylogenetic diversity (297), and peak evenness (0.82 ± 0.12). The normal season showed the lowest richness (6.7 ± 4.8) and phylogenetic diversity (122), with moderate evenness (0.78 ± 0.2). Dry season communities were taxonomically uneven, dominated by Diptera (78.0% abundance), primarily Chironomidae and Simuliidae (75.4%), with Simulium and Chironomus alone composing 45%. Seasonal hydrological disturbances were the main drivers of diversity and structural changes. Increased turbidity was correlated positively with declines in richness (R2 = 0.24, P = .009), abundance (R2 = 0.53, P = .001), and phylogenetic diversity (R2 = 0.12, P = .078), but negatively with evenness (R2 = 0.30, P = .006). Environmental disturbances enhanced biodiversity by altering species interactions and community organization, with the net effect depending on habitat conditions.