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Biodiversity in Urban Spaces
World Environmental Health Day falls on the 26th of September every year which is set by the International Federation of Environmental Health and its purpose is to raise awareness of the significance of the health of our environment. Urban spaces are a threat to our environment through Urban Creep which massively reduces refuge for wildlife. In this post we discuss the ways in which urban biodiversity can be helped and amplified by Sustainable Urban Drainage Solutions (SUDS).
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The Importance of SuDS and Creating Habitats in Urban Areas
What are SUDS
SUDS or Sustainable Urban Drainage Systems are different methods we use to manage stormwater, with a focus on mimicking natural processes. These methods are meant to reduce the risk of surface water flooding, make us more resilient to drought and help reduce the risk of sewage spills into our waterways.
Why wildlife in Urban Areas is important?
Cleaner Air
Studies estimate ambient air pollution causes over 4 million premature deaths annually as well as the general negative impact on health and increased risk of cardiovascular and respiratory diseases Article. Green spaces in urban areas act as natural pollution barriers and help filter the air we breathe. Therefore, it is vital that any plans we undertake should consider implementing greener solutions.
Impermeable surfaces/flooding
The expansion of cities leads to more concreting of green spaces reducing surface water absorption as these surfaces are impermeable. This in turn can lead to dangerous standing water and flooded homes. Wild spaces act like sponges helping to reduce these risks.
Pests
More habitats for smaller animals will attract larger prey animals. Birds, like sparrows and swallows, feed on insects, while bats consume large quantities of mosquitoes and other insects at night. In fact, bat nesting boxes have been used in Italy to combat mosquito populations as a natural alternative to pesticides. Similarly, urban foxes help control rodent populations, which can otherwise lead to a spike in pest-related issues
Examples of SUDS and how they help
Rainwater Planters
Just like conventional water butts, rain planters are connected to a downpipe and roof gutter. However, these devices include a basin at the top of water butt, ideal for small plants improving the aesthetic of your outdoor space and biodiversity! The water from the roof feeds the plants and any excess infiltrates down into a container that can be used for other gardening purposes.
How they Help
- Similar to rain gardens they provide a habitat for insects and other pollinators but on a smaller scale.
- Supplying water that you can use to help water your other green habitats.
- Great aesthetic addition to your garden or public space.
- When installed in series along streets, rain planters can create green corridors that help urban wildlife move more freely and safely through urban areas.
BioSwales
BioSwales are shallow manmade channels covered in vegetation with sloping sides that allow stormwater to be filtered and naturally infiltrate through the ground and replenish aquifers. Aquifers are layers of rock or other geological strata that can absorb water and allow it to flow which are viable and vital stores of water that can be utilised in drier periods.
How they Help
- Depending on the vegetation used can be used as a refuge for smaller animals and attract larger prey animals.
- They filter the water which makes it safer water for the animals that use it.
- If planted with native grasses and shrubs, can act as migration corridors for small mammals, insects, and reptiles, helping them traverse urban environments safely.
- The slow-moving water can support aquatic insects, which are a crucial food source for birds and other wildlife.
Retention ponds/basin
They are manmade ponds designed to receive stormwater runoff an act as an artificial wetland, it is different to a detention basin in that a detention basin only temporarily stores the stormwater, a Retention basin will be permanently wet. Storm water is usually directed to these basins from non-permeable areas.
How they help
- These retention ponds can be especially important to amphibians who are losing ponds and wet habitats in urban areas. They in turn benefit us by acting as a natural pest control
- These ponds attract various bird species, including waterfowl, wading birds, and songbirds, by providing a reliable water source and feeding grounds.
Rain Gardens
Rain gardens are typically shallow areas of ground designed to receive water run offs from a roof, this will usually involve disconnecting a downspout from flowing directly into the storm drain. The area will be planted with plants that can withstand waterlogging and these act as a natural filter for the stormwater before the water returns to the system.
How they Help
- Provides a habitat that attracts insects and birds and other pollinators. Which in turn will help other plants and wildlife flourish.
- By filtering pollutants before water reaches local waterways, rain gardens help maintain cleaner streams and ponds, supporting healthier aquatic ecosystems.
Green Roofs
Green roofs is exactly how it sounds. Growing vegetation on the side of your roofs absorbs some of the stormwater which collects on there, which in turn reduces the amount that ends up down the downspout and into our sewers.
How they Help
- Apart from looking visually pleasing, these act as an important refuge for smaller animals high up off the ground and can be especially important in cities if there is lack of garden space for this vegetation.
- Habitat for pollinators
- The cooler, vegetated surfaces of green roofs provide a refuge for wildlife during hot weather, helping to mitigate the urban heat island effect.