Background: When we build ponds in urban areas, they can play a number of important roles: managing floodwater, cooling the urban environment, removing pollution, improving the appearance of built-up areas and providing a habitat for wildlife. However, these different functions often require different forms of management, and so urban managers typically prioritise one or a small number of purposes. We were interested in the biodiversity value of ponds in Bradford in the UK.
What we did: My MSc student, Andrew Noble, surveyed a series of 21 sites across Bradford including 11 ponds that were prioritised for biodiversity, 6 ponds that were prioritised for amenity (usually park lakes and other ornamental features), and 4 ponds that were used as overflow ponds for water management. He surveyed aquatic plants and aquatic invertebrates to investigate patterns of biodiversity. This was then compared against what would be expected from high quality ponds of similar size (called a “reference site approach”). The results showed that the urban ponds were generally of very low quality, and that unsurprisingly the biodiversity ponds tended to contain higher numbers of animals and plants. However, this was not always the case and some amenity and overflow ponds contained more species despite not being managed for biodiversity. Finally, Andrew talked with managers who, while obviously enthusiastic about biodiversity, were unaware of important local factors that were influencing their sites, such as run-off from local sports fields which were likely contributing to algal blooms.
Importance: There have been a range of studies (including some by me) which have suggested that urban ponds can provide substantial benefits for biodiversity. However, these high value ponds are relatively rare, and it is important that we understand what factors result in some ponds being of high value while others are not. This study suggests that management could play a major role.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Poor ecological quality of urban ponds in northern England: causes and consequences”, was published in the journal Urban Ecosystems in 2014. You can find this paper at the publisher’s website.
Image credit: tpsdave, http://bit.ly/11ozTHF, Public Domain.