Pond and wetland (photos)
Pond and wetland (photos)
Fresh water is, of course, the home of amphibians and fish. There are also many insects, plants, birds and mammals that live only in or near water. There are still further creatures that just visit water, to drink or feed.
To attract some of these various species to the reserve, in summer 1998 we created the Millennium Pond and Wetland. Initial construction took a week of digging and shaping by mechanical excavator, and an additional two months of volunteer work.
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The result is a collection of mini-habitats, ranging from the mud at the bottom of the ponds to the trees on the surrounding bunds. Each accommodates a different natural community.
The pond is filled only by surface run-off, creating further variation as its level changes through the year. (Click on the diagram, left, for more details.)
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Like the new woodlands and hedges, some parts of the pond and wetland will take years to mature. Whatever stage they are at, though, there will nearly always be some wildlife activity observable. You can watch it from the path, the bridge or the jetty. All these will be reachable by wheelchair by the time we finish the work.
The stream that separates the two fields forms its own mini-habitat. It provides a safe breeding place for insects and is a thoroughfare for other small creatures.
Why have a pond?
We wanted a pond for two reasons. The first was that it would add to the biodiversity* of the reserve, which had no standing water on it. It would attract and support aquatic and damp-loving species of plants and animals not found elsewhere on the Wildlife Area. Also, a large number of 'dry land' birds and mammals visit ponds in order to drink and feed.
*"Biodiversity" is conservationists' jargon for the range and number of species in an area and how they interact.
Ponds are unrivalled as a means of maintaining or improving biodiversity. At least two-thirds of Britain's populations of wetland plants, animals and birds inhabit ponds (as opposed to lakes or rivers, for example). Some of these pond and pond-side dwellers are easy to see, including:
birds (reed warblers, for example)fish (such as sticklebacks)amphibians (frogs and newts)molluscs (pond snails; ram's horn snails)pond-living insects and other invertebrates (diving beetles; water boatmen), andpond-hatched insects (damselflies; mayflies).There are many more creatures that go unnoticed. These include small bottom-living species, the various inhabitants of muddy margins and the myriad invertebrates that breed only on aquatic plants. From a conservation point of view, these are just as important as the larger and more colourful inhabitants. Each needs the other, with every species playing its part in a series of intricately interrelated communities.
The basis of life for all these creatures is the plants found in and around ponds. The margins of ponds are matched only by tropical rain forest in their rate of production of plant material. A square metre of either can, typically, increase its ' biomass' (the amount of living matter on it) at the rate of more than 5 lbs (2 kgs) a year. Grassland, hedges and woodland are, at best, only half as productive.
Even less productive is open water; typically, 90% of a pond's plant mass is on its margins. Ponds make their greatest ecological contribution at the edge and in the shallows. Partly this is through the abundance of plant matter and partly because of the greater amounts of light and oxygen there.
The other reason for making the pond and wetland was to help us meet our other two objectives - amenity and education. Ponds and wet places are interesting to people, especially children, and pack a lot of variety and wildlife activity into a small space.