Contrasting metacommunity patterns of fish and aquatic insects in drainage ditches of paddy fields

• Published in: Ecological research Vol. 37; no. 5; pp. 635 - 646
• Main Authors: Iwamoto, Hideyuki, Tahara, Daisuke, Yoshida, Takehito
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.09.2022; Blackwell Publishing Ltd
• Subjects: Agricultural management; Aquatic insects; assembly mechanism; Autumn; Community ecology; Connecting; Dispersal; Dispersion; Distance; Ditches; Downstream; Drainage; Drainage ditches; Dynamical systems; Environmental factors; Fields; Fish; Flood management; Habitats; Hydrology; Insects; overland and watercourse distances; Redundancy; Rice fields; River basins; Rivers; seasonal flow fluctuation; Spring; Spring (season); Structures; Summer; temporal variation; Temporal variations; variation partitioning; Water depth; Water management
• ISSN: 0912-3814; 1440-1703
• DOI: 10.1111/1440-1703.12334

Understanding temporal variation in mechanisms and factors shaping metacommunity is an important issue of community ecology. The relative importance of different assembly mechanisms, such as dispersal and environmental filtering, can vary through time in dynamic systems, whereas it is still unclear how different dispersal modes affect temporal patterns of the variation. We investigated metacommunity structures of fish and aquatic insects with flying adults in spring, summer, and autumn in drainage ditches of paddy fields in the Kita River basin, Japan, where agricultural water management and flood events cause seasonal flow changes. Using redundancy analysis and variation partitioning, we examined how the variation of these metacommunity structures was explained by local environmental factors and two types of spatial factors (overland based and watercourse based). Fish metacommunities were mainly influenced by local environmental factors (e.g., water depth) in summer, and by watercourse‐based spatial factors (e.g., distance to downstream rivers) in spring and autumn. As fishes are obligate aquatic dispersers, increased hydrological connectivity among habitats in summer weakens the dispersal limitation from downstream rivers and enables species to track environmentally preferred habitats. In contrast, only overland‐based spatial factors (e.g., spatial patterns based on overland distance) significantly affected aquatic insect metacommunities in summer and autumn. These results suggest that regional and landscape variables can influence their metacommunity patterns more than the local environment. We conclude that the dynamic nature of the environment and dispersal modes can interactively influence metacommunity structures in temporally connecting habitats. Fish metacommunities were mainly influenced by local environmental factors in summer, and by watercourse‐based spatial factors in spring and autumn, as hydrological connectivity among habitats improves in the summer. In contrast, only overland‐based spatial factors significantly affected metacommunity structures of aquatic insects with flying adults in summer and autumn.