Flow regime shapes seasonal patterns of fish species richness and abundance in main and branch channels of a rice irrigation system

摘要: Current modernization of an irrigation system degrades fish habitats in quantity and quality is a significant concern for biodiversity conservation management ecosystem services rice farming landscapes. Irrigation systems consist various types channels, whose hydrological hydraulic heterogeneities can contribute to the coexistence diverse species this flooded habitat. We compared seasonal patterns richness abundance between main branch channels which have different functions with flow temporality magnitude: (mean width 425 cm mean discharge 0.467 m3/s period) (176 cm 0.115 m3/s, respectively). The are small temporary, but densities were not smaller than during period. Further, clear positive hysteretic loops found indicates that gradually increased hydroperiod. Water velocity strongly constrained partially because slow-flow patches at microhabitat scale larger vegetation coverage. also provided deeper non-irrigation period contributed maintain abundance. Therefore, managing both as indispensable, interconnected channel network be key habitat system.