FACT: A key test of sustainable development is the extent to which biodiversity remains uncompromised by development
WHICH MEANS THAT: A sustainable development should not adversely affect the wildlife habitats with which it is directly or indirectly associated and wherever possible should enhance those habitats.
LOWLAND ACIDIC VALLEY MIRES are an example of wildlife habitats that are increasingly threatened by land development and have declined to such an extent that they are a 'threatened' UK wildlife habitat.
What are Lowland Acidic Valley Mires?
Lowland acidic valley mires are areas of land usually located in valley bottoms which because of their high groundwater levels and accumulations of peat have developed special fauna and flora found in no other wildlife habitat.
These valley mires are increasingly threatened by development because they are very susceptible to land drainage and pollution. Almost all of these habitats in Europe occur in the UK and almost all of those habitats occur in southern England, from Dorset across to Kent.
The plant and animal communities that live in valley mires are unique to that habitat and are dependent upon strong acidity and low levels of calcium and other nutrients. Studies by The Environmental Project Consulting Group over many years have shown that while many acidic valley mires have these characteristics, almost all of them have areas that do not.
So what is happening?
A significant proportion of valley mires are being degraded by calcium pollution which raises the pH and affects the chemical balance of mire waters. This in turn alters the flora and fauna (eg. mosses, herbs and dragonflies) such that their fundamental community characteristics are altered for the worse.
Excess calcium enters acidic valley mires through streams and drains arising off adjacent developed areas and also from calcium rich groundwater emerging in valley mires as springs and seepages.
We strongly suspect that the main source of calcium within developed areas is derived from the solution of lime used in concrete and many common building products. Concrete is widely used in house foundations, drain pipes, car parks, roads and other constructional elements of our society. Calcium also occurs in limestone chippings (scalpings) used in path and road foundations and even in recycled road scrapings.
And the solution?
The precautionary principle should apply. Before any new development goes ahead in or near these threatened and heavily protected lowland acidic valley mires, it is essential that they are protected from calcium rich surface and groundwaters. This can be done by directing such water away from the site and, where this is not possible, by using non-calcareous materials such as clayware and plastic pipes. |