Wild in the city

I've always had a fascination for the wild parts of the city, and admired those plants and creatures that make a living in spite of humans. Of course, compared to other places, the biodiversity can be rather small, but in some ways the city is the ultimate multi-ecology environment, with each garden having its own microclimate and resultant suitability for colonisation.

For a long time the dominant trend in city gardening has been micromanagement: designing and building a garden around its human occupants and creating sharp edges, very few wild parts. I think that with the current interest in matters ecological that is starting to change.

But in any case, humans are not capable of absolute control of the environment. There are always natural processes that interfere, even with the most tightly governed of environments. For example, in the Biosphere projects, where the species that were grown or lived in a sealed glass dome were carefully introduced into a formerly sterile environment, other species that had not been deliberately introduced (ants) appeared and began to strongly affect the ecology.

In the city, which somehow seems quite sterile, species find a niche that they can exploit. Bats roost in old railway tunnels (for example in Sydenham Woods). Feral pigeons, which descend from cliff-dwelling rock doves, find ideal conditions in cities, with balconies and bridge struts taking the place of natural ledges and caves. Any under-maintained area can quickly become a rich pocket of life. The rear wall of my house, where water has dripped for years, has a small collection of ferns and mosses.

Natural processes such as rainfall and wind and earthquakes also cannot be controlled, obviously. I love finding stalactites and stalagmites in the city, where rainwater has dripped through layers of concrete and dissolved calcium carbonate, which is then deposited out as the water drips off onto the ground. Under the South Bank concrete monstrosities is a good place to see this.

The rainwater flows into storm drains, which are often the only remnants of rivers that once flowed through London. I take great delight in showing people where the Fleet River used to enter the Thames. To the west of St Paul's Cathedral, it was once wide and deep enough for boats to navigate at least to Holborn Viaduct. If you walk the area (it runs roughly where the railway line goes from Blackfriars to King's Cross) you can see how the surrounding areas slope down towards the old river channel. The Fleet was gradually covered over, as were many other rivers, even in central London. It does still exist as a storm drain, coming out under the Blackfriars platforms.

Canals, man-made and often rather unsavoury-looking, are hotspots for wildlife observation. It is very helpful now that bodies like British Waterways now keenly promote the environmental impacts of the canals. I observed a cormorant taking an eel in the Regent's Canal, which runs alongside Queen Mary College. The eel was big, and the cormorant struggled to swallow it for around half an hour, dropping and recatching it several times. Eventually it flew away, but with the eel's tail still protruding from its beak.

BBC news report of a similar encounter: http://news.bbc.co.uk/1/hi/wales/8097291.stm