Background: Urban ecosystems are becoming increasingly important as areas for biodiversity conservation, as we begin to recognise the importance of preserving natural habitat within heavily modified environments for both wildlife and human well being. Urban ponds are a key part of this network of habitats within cities, and are commonly found in parks, gardens and industrial estates. In fact, there are an estimated 2.5-3.5 million garden ponds in the UK alone, which could have an area the size of Lake Windermere!
What we did: I was invited to submit a review of the biodiversity value of urban ponds. This later expanding beyond simply describing biodiversity patterns to include the ecological processes that generate those patterns. I describe a wide-ranging set of potential negative impacts on urban pond biodiversity, including invasive species, mismanagement, pollution, and habitat destruction. However, I also took great care to highlight the benefits of these habitats in terms of their use in controlling stormwater, their role in local aesthetics, and the way in which they provide access to nature in inner cities. These ponds can be a fantastic resource if managed well.
Importance: Research on urban water bodies has been growing, and this review highlights both the work that has been done up to now and the gaps in our current knowledge that should be filled in the future.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “The ecology and biodiversity of urban ponds”, was published in the journal WIREs Water in 2014. You can find this paper at the publisher’s website or for free at Figshare.
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.
Background: The management of water in urban areas can be a problem, because rainfall rapidly runs off impervious surfaces like pavements and roads. This means the water quickly enters rivers and streams, which then flood. City managers reduce the rate at which water enters rivers using stormwater management facilities, which often include ponds to hold back the stormwater. These ponds are usually managed just for water retention, but they could potentially form a very useful habitat for aquatic plants and animals in cities.
What we did: We looked at 20 of these stormwater management ponds (SMPs) to see how many animals and plants were using them. We also compared those 20 ponds against 10 other ponds that were not used for stormwater management, but were found in roughly the same area. We showed that the water chemistry in the SMPs was often high in salt, and that the amount of salt in the ponds was related to the amount of urban land cover (which makes sense: much of the salt would have been road salt washed in during snow melt). However, despite some differences in water chemistry there were no significant differences between the SMPs and the other ponds in the diversity of animals. We conclude that it is not the management, per se, that affects the ponds, but the landscape within which they are found.
Importance: Management of particular habitats frequently has to prioritise one function over another. Stormwater management is a major concern in many areas, and so there may not be much willingness to detract from the role of ponds in managing run-off in order to benefit biodiversity. We showed that this may not be necessary: if the ponds are in a relatively low-intensity urban area then they may contain high biodiversity regardless of management.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Stormwater ponds can contain comparable biodiversity to unmanaged wetlands in urban areas”, was published in the journal Hydrobiologia in 2014. You can find this paper at the publisher’s website.
Background: Ponds have been identified as a very important habitat in the landscape. They enhance regional biodiversity, help control floodwater, reduce pollution in run-off from agricultural and urban land, and provide greenspace and biodiversity in urban environments. However, because of their small size (typically less than two hectares), they have been neglected by scientists until the last couple of decades.
What we did: This study used a large dataset of 454 ponds that had been surveyed in the north of England to identify all of the invertebrate and plant species that inhabited them. A wide range of physical, chemical and biological variables were also measured and, as the title of the paper suggests, we investigated which of these variables were related to the species richness of different plant and animal taxa. We were able to predict a reasonable amount of the diversity of invertebrates in general, but predictions varied between groups of invertebrates. In general, more shade and a history of drying up reduced the diversity of all groups.
Importance: It has been shown that landowners and managers tend to manage ponds and other natural resources using “received knowledge”. in other words, there is little evidence base for such management. Our study demonstrated a few important relationships which can be used to inform this kind of management.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Environmental correlates of plant and invertebrate species richness in ponds”, was published in the journal Biodiversity and Conservation in 2011. You can find this paper online at the publisher, or on Figshare.
The black bog had him by the feet; the sucking of the ground drew on him, like the thirsty lips of death. […] he tossed his arms to heaven, and they were black to the elbow, and the glare of his eyes was ghastly. […] Scarcely could I turn away, while, joint by joint, he sank from sight.
Lorna Doone, R.D. Blackmore
What do you think of when you think about wetlands: ponds, lakes, streams, rivers? Humankind needs water to drink, irrigate crops, and clean ourselves. However, our view of water tends to focus on the negatives: drowning, dirt, disease, and decay. Words like “bogged-down” and “swamped” have entered everyday use. In some ways Carver Doone’s plight represents the fears that we have about wetlands. But I want to make the case that these wetlands are misunderstood heroes of the natural world. Read More »