Ponds: a quick win for biodiversity
Biodiversity and Biodiversity Net Gain (BNG) is undoubtedly a hot topic high on everyone’s agenda for 2023. Whilst some local authorities are already planning and delivering BNG, all are now gearing up to implement the mandatory 10% net gain that developers and landowners will be required to deliver across their projects, becoming effective in November 2023. But it’s not just developers and estate owners who are considering their biodiversity responsibilities – householders and communities too can make a real difference to habitat creation and addressing the impacts of climate change.
Increasing biodiversity
When it comes to increasing biodiversity, planting trees is the obvious solution and does, of course, have great environmental benefit. Trees provide habitats for a multitude of organisms and, from some of our largest species down to the smallest, are an important food source for countless species and provide a foothold for often overlooked epiphytes like mosses and lichens. Trees and woodlands are often the ‘go to’ option when habitat creation, biodiversity improvement or rewilding is considered for an area, and indeed it is likely that much of post glacial Britain was covered by woodland – the so-called wildwood (do you see what I did there?).
But there is an unfortunate problem with woodland habitat creation: it takes years, even decades, before a newly planted woodland reaches maturity and becomes that desired biodiverse habitat. This is often reflected in biodiversity net gain calculations where woodland creation, because of this long maturity, has a lower habitat creation ‘score’ than other, quicker maturing, habitats. Therefore, a larger area of planting may be required to achieve the necessary biodiversity net gain.
Dig a pond
So how do we create a habitat that is quick to mature and provides an environment that has similar potential for biodiversity?
The answer
is dig a pond. A well planned and well-located pond can be quick to mature and will
provide habitat for a wide variety of organisms. Unlike a
woodland (at least in its early stages), a pond requires very little maintenance in order to thrive.
No fish
A wildlife pond requires a different approach to an ornamental fish pond. Firstly, NO FISH. Unless you are planning a very large pond where a small number of native species may be possible, any introduced fish will soon clear the pond of invertebrates. No invertebrates will mean larger animals such as frog, toad and newt tadpoles will have no food source. The presence of fish can seriously deplete the potential for a wildlife pond.
Access for wildlife
It is important that wildlife can get in and out of the pond. A steep sided pond made of concrete or plastic will mean any animals getting into the pond will be unable to leave, including those that didn’t mean to enter. This means that poorly designed ponds can be a death trap to small mammals and reptiles. Design your pond with at least some gentle slopes, well positioned cobbles and branches can also be very useful additions.
Size doesn’t matter
The size doesn’t really matter, any standing water will attract wildlife, it may even be more beneficial to create a series of smaller ponds than one large one. Try to create a series of water depths, an area that is over 0.5m deep will allow over wintering animals the chance to survive the cold – ponds that are too shallow may freeze completely and so kill all hibernating animals.
Location
Location is important for a pond to flourish. It should receive as much sun as possible, a permanently shaded pond may not be successful. Also, if it is overshadowed by branches then it is likely to quickly fill with leaves which will seriously inhibit the life in the pond as the decomposition process removes oxygen from the water. Too much sun isn’t a problem as long as the pond isn’t in danger of drying completely for long periods. Occasional drying out isn’t a problem and may even be advantageous to some species.
Native plants
Animals will come to your pond, but plants won’t, at least not in short term. Use native plants where possible and research the best ones for the size of your pond; ponds can become swamped by a vigorous plant. Resist the temptation to put in a large lily in a small pond, the leaves will quickly cover the pond and shut out light. Marsh marigold, flowering rush, water plantain and purple loosestrife will provide a beautiful display of flowers throughout the spring and summer. Make sure that you only use low nutrient substrate to plant into, otherwise your pond will quickly turn into a green soup, due to rapid algal growth.
Maintenance
In the early years, a pond may need a little maintenance as the water nutrient balance becomes established. Allow the chance for the pond to become stabilised before rushing into remedial action and resist the temptation to use any kind of chemical control – trust in nature. If a plant becomes too vigorous or filamentous algae starts to take over, then some removal may be required. Do this in autumn before animals start to hibernate and leave the removed material on the side of the pond for a day or two to allow any removed fauna the chance to get back into the pond.
Wildwood’s pond projects
Wildwood Ecology has a proven record of designing and overseeing the creation of ponds. Projects have included the creation of successful compensation ponds as part of great crested newt district licence schemes and providing advice for pond creation as part of a site-wide management plan.
Get in touch if you are planning pond creation projects or to discuss how ponds can help you to meet the biodiversity net gain requirements for your project.
David Withington – Consultant Ecologist
