Small Ponds, Large Value: Comparing Macroinvertebrate Assemblages in Ornamental and Wildlife Garden Ponds in Urban Landscapes

Small water bodies can contribute to freshwater biodiversity in urban landscapes, yet the ecological value of garden ponds may vary with their design and management. We compared macroinvertebrate assemblages in five conventional ornamental and five ecologically designed wildlife garden ponds in urban and suburban settings around Vác, Central Hungary. Macroinvertebrates were sampled on nine occasions between September 2020 and August 2021, excluding December–February, across open-water, marginal-vegetation and submerged-vegetation habitats, yielding 810 subsamples. In total, 43 taxa were recorded, of which 42 were identified to species level and one to genus level. Wildlife ponds supported higher cumulative taxon richness (33–40 taxa per pond) than conventional ornamental ponds (3–19 taxa); 20 taxa occurred exclusively in wildlife ponds, two exclusively in conventional ornamental ponds, and 21 in both types. Mixed-effects modelling indicated significant differences in taxon richness between pond types and among the nine non-winter sampling months within the single study period, but no significant interaction. Temporal differences could not be separated into seasonal and interannual effects. Wildlife ponds also showed greater among-pond compositional similarity based on Jaccard and Sørensen–Dice indices. These findings suggest that biodiversity-oriented garden ponds can provide valuable small-scale aquatic habitats and complement larger elements of urban blue–green infrastructure, contributing to biodiversity conservation in urban and suburban landscapes.