‘a pond’

[POST BY LAB-TEAM 1]

On Oosterdokseiland we found an unexpected place: ‘a pond ‘, created by the delay in construction due to the crisis. We saw it as a potential for biodiversity, but how can it be transformed to a space for biodiversity?

It is difficult to be specific about what defines a ‘good’ pond for wildlife. Different types of ponds support characteristic flora and fauna, depending on their origin and local environmental factors such as substrate, water source and surrounding habitat. However, there are general features that, if present, are likely to encourage ecological interest.

Water quality is important. Ponds with a high ecological interest are usually associated with water that is free of pollutants and has low levels of soil nutrients such as nitrogen, phosphate and potassium. Ponds with structural variation are more likely to provide opportunities for a higher number of species than ponds with a more uniform structure. For example, small variations of pond-bed topography allow a greater number of dragonfly species to co-exist with each other. In a more uniform environment, smaller less-competitive dragonfly species will be less able to hide and avoid predation by the larger dragonfly species.

Native plants are preferable to ornamental ones because they support a greater diversity of animal species. It is important to remember that too much pond vegetation can have a detrimental impact and can cause undesirable chemical changes such as daily oxygen depletion. Ideally, a pond with approximately 35 per cent open water and 65 per cent vegetation cover during late summer is recommended, as some species require areas that are relatively plant-free.