Characterisation of constructed ponds and factors influencing their macroinvertebrate communities on the lower Waikato River floodplain, New Zealand

Abstract

ABSTRACT Ponds are increasingly being constructed to enhance amenity values in human-dominated lowland landscapes, but little is known of design features that influence macroinvertebrates which can provide important food resources for fish and waterbirds. We quantified pond characteristics, sampled benthic and water-column macroinvertebrates in winter, and related abundance, biomass and community composition to characteristics of 34 ponds on the lower Waikato River floodplain, northern New Zealand. Compositionally different macroinvertebrate communities occupied water-column and benthic habitats. Landscape setting had a significant effect on benthic composition in terms of biomass, while the independent effects of frequency of pond drying or flooding, respectively, influenced benthic (abundance, biomass) or water-column (abundance) communities. Distance-based linear models highlighted physicochemical conditions, water depth regimes and riparian vegetation composition as key variables accounting for dissimilarity in total macroinvertebrate biomass between ponds. Our results indicate that managing hydrological stability of ponds in terms of permanence and flooding influences the composition and biomass of invertebrate communities. Within this hydrological template, design of appropriate depth regimes and riparian conditions can enhance accrual of macroinvertebrate biomass, thereby increasing food resources for fish and waterbirds.