14 January 2011

Limestone Fynbos - post fire

To me fynbos after a fire is... um, er... yum!

I'm not a pyromaniac but fynbos requires fire to maintain species diversity, and the rejuvenation after a burn is magical. Take for example the pretty Fire Lily (Cyrtanthus fergusoniae), only seen after fire:



Basically fire clears all the big bushes and makes space for a host of annuals, geophytes and so-called fire perennials - short-lived perennials which flower only in the first few years after a burn. Like the yellow Bobartia macrospatha, seen below:


Carpets of Prismatocarpus sp.

Apart from being pretty in a monochromatic kind of way, the burnt skeletons of Protea and Leucadendron bushes provide clues about the age of the veld prior to the burn, and the intensity of the fire.



Looking at the unburnt leaves and seed heads on these pincushion (Leucospermum) bushes tells me it was a cool fire of low heat intensity. Considering the high fuel load of the adjacent veld which was clearly old and woody, and the well maintained fire breaks this was clearly a controlled burn. These are typically done on cool, windless days so that it's easier to 'manage'.



Considering the danger of uncontrolled wild fires, this practise is understandable. However cool fires favour the germination and success of certain plant species (those with small fine seeds), so one does need occasional hot fires to maintain species diversity.

Veld fires vary in a number of ways - viz. season of burn, intensity and frequency (how often). It is thought that the resulting patch mosaic of different fire types - in space as well as time - is one of the main factors that drove the evolution of species, and which has resulted in the incredible diversity of fynbos.

(end of lecture - or at least, I'll try)

Seedling of Leucospermum with characteristic red nectaries on the leaves (above) and Protea seedlings (below).

Walking through the veld (the south african word for 'bush'), Koensrust farm appears to be well managed: there were no alien invasive plants (which form thickets elsewhere around Vermaaklikheid); and there were well maintained firebreaks. I started my walk in newly burnt veld and ended up going through very old / mature limestone fynbos, which made a fascinating comparison. More about the latter in another post.

A blister beetle foraging pollen on Bobartia sp. This unsual plant looks just like a reed with long thin stem-like leaves. It reveals its geophyte identity only when in flower.



Aristea sp.

3 comments:

  1. I love your blog! :)thank you

    Fiona (not Kipper but he loves it too I'm sure)

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  2. Thanks for checking in, Fi. Hope to do a walk again with you soon!

    ReplyDelete
  3. Wow, those fire lilies are beautiful!

    ReplyDelete