Effect of the structural complexity of aquatic macrophytes on epiphytic algal, macroinvertebrates, and their interspecific relationships

Aquatic macrophytes may have a significant effect on associated communities such as epiphytes and macroinvertebrates, which through the structural complexity of habitat, provide shelter, resources, and interspecific interactions. We tested the hypothesis that the structural complexity of macrophytes positively modifies epiphytes and macroinvertebrates and that the interspecific interactions of epiphytes and macrophytes positively influence macroinvertebrates by synergism of epiphyte availability and increased habitat complexity. The macrophytes presented different structural complexities, ranging from low (Cyperus articulatus), medium (Nymphaea pulchella) to high complexity (Eichhornia crassipes and Ludwigia helminthorrhiza). The richness, diversity, and biomass of epiphytes presented a significant difference and positive relationship with the increase of the structural complexity of the macrophytes. The synergism between the structural complexity of the macrophytes and the epiphytic biomass (r(2) = 0.37; p = 0.0002), increased the biomass of macroinvertebrates (r(2) = 0.47; p = 0.003). The functional traits of the epiphytes were directly related to the morphology of the macrophytes with the unicellular, pedunculated, and firmly adhered dominating. The dominance of these traits indicates the absence or low disturbance (e.g., rain) in the studied site. The responses of the functional characteristics of the epiphytes are important to understand ecosystem functioning and dynamics. Therefore, we conclude that epiphytes showed a positive relationship with the structural complexity of the macrophytes. Moreover, macroinvertebrates showed a positive relationship with the increased macrophyte morphological complexity and increased biomass of epiphytes. The management of macrophytes with different structural complexities can be a strategy to recover the biodiversity in tropical aquatic ecosystems.

Automated summary

The study demonstrates that the structural complexity of aquatic macrophytes positively influences epiphytes and macroinvertebrates, with a synergistic effect observed between epiphytes and macrophytes increasing the biomass of macroinvertebrates. The findings suggest that managing macrophytes with different structural complexities could be a valuable strategy in enhancing biodiversity in tropical aquatic ecosystems.