Patterns and correlates in the distribution, design and management of garden ponds along an urban-rural gradient

Abstract

Urbanisation results in the loss and alteration of natural wetlands and ponds. However, garden ponds in cities and towns can act as rich reservoirs of aquatic biodiversity and stepping stones for dispersal. Homeowners with a range of different motivations, including biodiversity values, install garden ponds. Here, our main aim was to study whether the design and management choices of garden pond owners was dependent on the location of ponds (capital city vs. countryside), when ponds were installed (pond age), or whether fish were introduced. We surveyed 834 garden pond owners across Hungary using a citizen science questionnaire, asking questions on pond size, location, construction date and materials, vegetation structure, introduction of fish and management practices. From 753 validated responses, we found that the introduction of fish into ponds and high urbanisation were strongly associated with local features and management practices, especially large ponds with a water circulation feature, irrespective of pond age. A typical garden pond in Hungary is ∼20 m2, <10 years old, made of rubber (PVC) lining, contains fish, aquatic vegetation and circulating water, and is actively managed. There was a spatial separation of ponds based on local features between ponds in the capital city (Budapest) and elsewhere. These findings suggest that garden pond owners in cities are likely to make different choices in pond design and management compared to owners in regional areas. Our results also suggest that pond owners may primarily select management practices to improve habitat quality for ornamental fish. Our findings have important implications for maintaining aquatic biodiversity in urban areas, where garden ponds may be the only aquatic habitat available.RESEARCH HIGHLIGHTSHungarian garden ponds ≤ 200 m2occur in both large cities and small villagesMost garden ponds we sampled in Hungary were built in the last decadePond design and management differs between Budapest and regional areasPond design and management practices are influenced by ornamental fish stockingPond owners frequently drain ponds to remove sediment and leaves and use algaecides

Effects of urbanisation, habitat characteristics, and management on garden pond biodiversity: a citizen science approach

“…Despite the introduction of fish into 85% of ponds, amphibian reproduction was observed in 60% of the ponds, indicating that some species are able to co-exist with fish (Hamer et al, 2021; Kloskowski et al, 2020). In another study focusing on local pond features in the same set of ponds, it was also found that the introduction of fish was a significant predictor of garden pond design and within-pond features including management practices (Hamer et al, 2023). This result implies a potential conflict between creating ponds with the main aim of keeping ornamental fish and the potential of garden ponds to support native biodiversity.…”

“…Many amphibian species prefer well-vegetated or large ponds (Arntzen et al, 1997; Péntek et al, 2017; Rannap et al, 2013), which was supported by our results that several species such as Bombina bombina, Pelobates fuscus, Triturus dobrogicus were positively associated with aquatic vegetation in our ponds. Due to the larger size of the rubber-lined ponds, rubber substrate had a significantly positive effect on the presence of amphibians and their tadpoles, also odonates, birds, and wading birds (Hamer et al, 2023).…”