Friday 5 August 2011

A Little Weekend Ecology Brainteaser

I'm away from the computer for a few days as my little brother is getting married tomorrow, so while I'm gone, here's a little photo that I took while fiddling around with my DSLR (I'm still learning...).


The fern on the left is Asplenium scolopendrium, a British native. I'm not entirely sure, but I think the other is Cystopteris fragilis - I'm thinking that because of the little ridges on the fronds.

Now, I like taking photos of ferns. Anyone who keeps in touch with my other blog knows that. But there's a scientific reason for taking this photo above and beyond my own pteridophilia. It's a lovely example of a stage of succession - the progression and development of communities from bare substrate to mature assemblage.

My questions to you:
  1. Is this primary succession or secondary succession?
  2. How far along in the succession is this community (use Clements' phases if it helps)?
  3. Are the species shown r-selected or k-selected?
  4. Do you reckon this would work as a good recap exercise for A-level students who've just studied succession?
Have fun, don't assume the previous commenter has got it right, and I'll be back with the answers on Monday night.

2 comments:

  1. So, not interested then? :(

    ReplyDelete
  2. Assuming that a stone wall counts as bare rock then it's a primary succession, as these plants couldn't make this a home until the mosses had done their work. Nevertheless, a rockface is no place for K-selected plants. They're past grasses but not trees. Using reason rather than research - which I'll grant you is less adequate - I'd say they are r-selected species in the shrubby stage of a primary succession. Get some Buddleia in there to break up the deep rock and to dump mass humus in the surrounding area (because nothing puts down organic matter like effing Buddleia!) and this could find itself being well on the way to a climax community.

    ReplyDelete

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