Effect of removal of free-floating macrophytes on zooplankton habitat in shallow wetland

Abstract

Key-words:submerged macrophyte, macrophyte habitat, zooplankton, species diversity, shallow wetland Submerged macrophytes improve the structural heterogeneity of microhabitats in aquatic ecosystems, often providing an important habitat for zooplankton. However, excessive development of free-floating macrophytes on the water surface can reduce the biomass of submerged macrophytes and result in a relatively simple habitat structure. We hypothesized that controlling the development of free-floating macrophytes would result in a more complex habitat structure by promoting the development of submerged macrophytes. After applying three experimental treatments (NR, no removal; IR, intermediate removal; CR, complete removal of free-floating macrophytes), we found that CR of free-floating macrophytes improved the growth and development of submerged macrophytes and supported a large zooplankton assemblage. However, the largest zooplankton assemblage (in terms of abundance and diversity) was recorded after the IR treatment. Although submerged macrophytes were abundant in the CR treatment, the number, abundance, and density of zooplankton species were much lower than those in the IR treatment. Preferential selection of different macrophyte types by zooplankton presumably led to variation in plant utilization of niches, and the simultaneous presence of different macrophyte life forms created a complex microhabitat structure that induced high species diversity and zooplankton density. RÉSUMÉEffet du retrait des macrophytes flottants sur l'habitat du zooplancton dans les zones humides peu profondes Mots-clés :macrophytes submergés, habitat des macrophytes, Les macrophytes submergés améliorent l'hétérogénéité structurelle des microhabitats dans les écosystèmes aquatiques, offrant souvent un habitat important pour le zooplancton. Cependant, le développement excessif des macrophytes flottants à la surface de l'eau peut réduire la biomasse des macrophytes submergés et aboutir à une structure de l'habitat relativement simple. Nous avons supposé que le contrôle du développement des macrophytes flottants se traduirait par une structure de l'habitat plus complexe en favorisant le développement des zooplancton, diversité des espèces, zones humides peu profondes macrophytes submergés. Après l'application de trois traitements expérimentaux (pas de suppression, suppression intermédiaire, et la suppression complète des macrophytes flottants), nous avons constaté que l'élimination complète des macrophytes flottants améliore la croissance et le développement des macrophytes submergés et favorise un important assemblage de zooplancton. Cependant, la plus grande communauté de zooplancton (en termes d'abondance et de diversité) a été constatée après le traitement de suppression intermédiaire. Bien que les macrophytes submergés soient abondants dans le traitement de suppression complète, le nombre, l'abondance et la densité des espèces de zooplancton ont été beaucoup plus faibles que dans le traitement de suppression intermédiaire. Une ...

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