Monday, October 08, 2007

succession

There is an ecological theory that ecosystems have what is called a climax state. Stop sniggering at the back. Climax is, to grossly oversimplify, that state at which an ecosystem will arrive if left to it’s own devices. Setting aside issues of if and when human activity is to be regarded as part of an ecosystem, and whether climax is a static or a dynamic equilibrium (it’s dynamic, to my mind, by the way), the idea is that there is a path, or series of identifiable and categorisable states, that any system, all other things being equal, will follow on the way to climax. The process of moving through these states is known as succession. I did say it was a gross oversimplification.

Now, the key phrase here is all other things being equal. They aren’t. And never where. Go back far enough, and where I am now was a warm shallow sea. A bit nearer our time, and it was under a bloody great ice sheet. That’s why the place I live is made of gritstone hills with the tops shaved off, exposing the limestone made from the reefs that grew in the warm shallow sea.

It’s been a fashion in conservation to try and achieve and conserve climax vegetation, and thus the fauna it suports, as it is regarded as the best and most stable habitat. This leads to things like the pumps that have to run to keep Wicken Fen wet, and the removal of sycamores from woods. Bottom line is, Cairngorm possibly but very debatably aside, there is not one habitat in the UK that is in any way as it is without human activity. We have no wilderness. Even cairngorm is less than wild, due to the lack of wolves, and all the other stuff we exterminated to make this island more comfortable. Even the deep dark lakes that hide the relict populations of arctic chard are changed, chemically and now thermally by our influence.

Our environment is based on arrested, or manipulated succession. This is where we live. However, the rules are about to change. The other, non equal things are going to get even less equal. Climate change is already pushing species further north, some faster than others, and the subtle webs of interdependence that keep the whole shebang together will warp and deform, some strands will snap, and some new threads will emerge. Holm oaks in Kew Gardens, a mediteranian species that actually does quite well in the south west, are taking a kicking from a moth, because it has migrated north faster than it’s predators. And before you start banging on about survival of the fittest, that moth is going to last about a week if all the oaks die. I won’t labour the metaphorical potential of that point.

We’ve made a good living out of a fairly stable system we have amended, controlled and fostered for about 4000 years, in some shape or form. And all the while we have been increasing the level of control, making life easier. I’m not so sure we can remeber how to be flexible enough to deal with what comes next, we’ve had too long a ride. When we have to get along with left overs, and each other, I don’t see us cutting it. The process of succession will kick in, but with a changed substrate, and a new set of variables, the climax will be different to those we’re used to.

It’ll take a bunch of critters with more flexibility, short generational turnover, big populations made of small individuals and a wide ranging appetite to succeed us. Things that are hard to kill, and willing to do what it takes to get by. You can probably see where I’m taking this by now. Think very small swarms of Daleks. But without the individuality. Think Insects. Arthropods. Roaches.

Under the fridge, the future!

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