The ecology of cities

As water flows along streams and rivers, maybe spreads out, and creates a habitat; so money flows and creates an industrial quarter in a city. Sometimes the river is diverted, or dries up, and the watery habitat disappears, and is replaced with something else. Sometimes too, money is diverted, and the industrial habitat disappears, and is replaced with something else.

When an industrial area loses its sustaining flow of money, a typical ecological succession ensues.

First to populate the newly vacated habitat is broken glass, graffiti and litter. These pioneer species indicate that the habitat is changing. These are typically followed by Buddleia and discarded shopping trolleys – hardier species than the pioneers, but slower to colonise. These species slowly spread to dominate the area over several years.

Later, when the area seems to have reached equilibrium, giant grazing animals appear. These noisy, smelly yellow animals feed on bricks and building materials, the carcasses of the inhabitants from the earlier times. These act as “ecological engineers”, species that significantly change the habitat. Where once skeletal structures were, there now are flattened areas of rubble. Encroaching at the margins of these are the pioneer species, but more significant are the new arrivals – temporary car parks and their attendant signs, cones, and cars.

Later still, a distinct breed of human re-emerges, having been all but chased out when the money dried up. These are the artists and artisans, living at the fringes of the economy and in need of cheap space. They generally form a mutually tolerant relationship with the few light-industry humans that survived the money drought.

These humans encourage a trickle of money to re-enter the area, at which point the noisy smelly yellow animals begin to reappear although these ones, unlike their forerunners, begin to convert the temporary car parks back into new buildings.

The climax community of such a succession is one of superficially attractive but over-priced city-living, and computer games developers. Typical species thus include young city professionals (lawyers, accountants, consultants) and computer programmers. The former head to the city centre to graze during the day and return at night; the latter graze in the area during the day and leave at night to rest elsewhere.

You don’t see with just your eyes

My undergraduate degree is in ecology, but I am a terrible field ecologist.  To me birds comprise robins, crows, pigeons, and all the other ones; and trees are all oaks or not-oaks.

In the summer between our first and second year we had to make a taxonomic collection – collect, preserve and identify examples of 15-20 species from a taxonomic group or closely related groups.  At my mum’s suggestion I chose grasses, and quickly expanded this to include sedges.  Prior to this I had always strolled along country paths and through woods and, whilst I always liked the setting, I only ever saw an indistinct green background.  But once I had to look and understand, that is when I really began to see what that green background was – and it was intricate and beautiful.  By the end of the summer I could spot a species of grass I hadn’t yet collected from several metres away amongst a riot of green, when all I used to see was a green background.  You see more when you know what you are looking at.

If you want to pick up field identification skills, it can be a bit daunting when you speak to someone who knows what every bird call and flash of feather belongs to, or what kind of geologic material that stone and those cliffs are.  But the best way to start is from the beginning.  First, learn to identify the really obvious stuff, the ones you see all the time.  Want to know about birds but don’t know the difference between a coot and a moorhen?  Go to the pond with a bird handbook, wait till you see one or the other, and look it up.  Don’t go out straight out looking for kingfishers, start with the ones you will see most often.  Quickly, you will be confident in identifying 75% of what you see if you know the most common ones.  Your eye is then attuned to looking for one you haven’t yet seen.  See with your mind, not just your eyes.