There was another interesting article in the Autumn issue of BBC Wildlife magazine on the importance of brownfield sites for wildlife.

We all think in terms of brownfield sites being derelict, dangerous and useless. But in fact it provides a whole range iof valuable, and often novel, habitat for wildlife. Indeed often brownfield sites are richer in wildlife than green belt land which tends to be managed and manicured by comparison.

Again the article isn’t online (although there is a short news report) so once more a few pertinent extracts.

Much has been made of the importance of brownfield for wildlife … there’s also an assumption … that it must be the priority for development in order to protect the countryside and the green belt
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a conflict between the need for economic development and the conservation of wildlife habitats near where people live.
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Often, though, the ideal solution is neither protection nor redevelopment but natural regeneration. Some of the pollutants in the soil and ground water of former industrial land can be broken down, neutralised and stored by microorganisms, fungi and plants … the environmental value of these natural decontaminants should not be taken lightly.
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Brownfield land is full of contradictions. On the one hand, many wildlife-rich green spaces in our towns and cities are, ironically, brownfield. They provide the green networks on which these conurbations depend. And on the other, brownfield is far from an exclusively urban phenomenon.
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There are countless brownfield sites … that may never become protected nature reserves, yet nonetheless are important refuges … landfill sites, scrapyards, car parks, skip depots, industrial estates and gravel pits.
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in Britain, some species now depend on the ‘surrogate’ habitats provided by brownfield sites … shrill and brown-banded carder bees … both species of bee now depend on brownfield in the Thames Gateway
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the last outpost of the silver-studded blue butterfly in the Midlands is a disused airfield at Prees Heath Common … the concrete runway, too expensive to remove, protects colonies of black ants that in turn protect the silver-studded blue caterpillars.
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brownfield sustains as many Red Data and nationally scarce invertebrates as ancient woodland.

Dereliction is not the sole qualification for brown field land. Many other places don’t fit the official definition, because they are functioning as intended: railway-line cuttings and embankments, motorway verges, canal towpaths, retail parks and the open spaces backing onto housing estates and enterprise zones … because they are urban or industrial, they are still lumped together as brownfield, and all are of unintended wildlife importance.
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Asphalt and piles of bricks are equivalent to heat-retaining heathland for basking slow-worms and common lizards. Warehouses and towers are like cliffs to nesting peregrines and kestrels. Railway ballast supports plants adapted to growing on limestone.
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disturbance opens dormant seeds in the soil and gives the ‘seed rain’ falling from the air a chance to germinate. Moreover, in brownfield land not used for food production or recreation, there is little or no exposure to herbicides, pesticides, fungicides and chemical fertilisers.

The importance of small, inter-connected wildlife havens is very noticeable, and brownfield clearly contributes much to this.

Here in west London we are lucky. There is a string of open green land running from Richmond north-west through Ealing, Harrow and Watford right out to the farmland beyond the M25. No one piece is more than about half a mile from the next, even if that next piece is only a range of large gardens or a brownfield area. And it is especially noticeable the extent to which birds use these green corridors — a definite SE-NW axis to bird flights is noticeable from my study window.

We do not need more office bocks or airports. We need all the open space we can get, even if that is scrubland, bushes and hedges. Although trees and meadows are just as valuable. Planners please note.