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Posted on July 24, 2015 @ 06:35:00 AM by Paul Meagher
This blog goes into further detail on the 12th permaculture principle that advises us to "Creatively Use and
Respond To Change". In my last blog on this principle,
I mentioned that ecological succession was one model that permaculture uses to understand change and promised to
address this topic in a future blog. The hope is that models of successional change might be useful for understanding
change and therefore using and responding to it more creatively.
The topic of ecological succession is huge and I cannot hope to do it justice in this brief blog. My goal is to simply to highlight a few ideas from the ecological succession literature that might be used as a starting point for thinking about how change happens in natural ecosystems. These concepts might prove useful for thinking about how change happens in other contexts, such as business or life in general.
The first concept that I think is useful for thinking about change is the hump diagram below that depicts how forest succession works. This diagram comes from the Wikipedia page on ecological succession.
The diagram is fairly self-explanatory about how forest succession works. All I want to do is point out that the hump diagram at the top used to depict this change encapsulates alot of useful information in a succinct form. It shows that some species have their day in the sun but are eventually replaced or dominated by other species that thrive
for awhile before they too are replaced or dominated. Eventually, in a mature ecosystem, one or more species comes to dominate the ecosystem. Note that some species don't completely disappear over time, they just become less dominant in the landscape. The end of this particular sequence has a couple of species dominating with a couple of other species
doing quite well (one appearing to rebound a bit) and one just hanging on. So succession doesn't necessarily involve completely replacing one species with another. It mostly involves changes in which species become dominant over time.
So the diagram gives us a way to think about what succession looks like over time but it doesn't give us much in the way of tools for thinking about why succession has this form. So the second set of concepts I want to discuss are some of the mechanisms that drive this succession.
One mechanism is called faciliation which is the idea that some species prepare the ground for later species. For example, the early species that emerge after a distrubance, the pioneer species, are often nitrogen fixers
that cover the ground and help to retain moisture in the ground. This moisture and nitrogen provides an environment for later species to enter and become dominant.
Another mechanism is inhibition which is the idea that some species become dominant by shading out or releasing alleopathic chemicals that cause existing species to become less dominant or die off.
Another mechanism is symbiosis where, for example, a nitrogen fixing tree helps another tree to grow while also benefitting from the moisture, wind protection, root exudates, or mycelial network associated with adjacent trees. One tree may appear dominant, but if the surrounding non-dominant trees were removed, the dominant tree might do less well
or die off. This phenomenon is often observed in suburban developments where a few trees are spared but do less well as singular trees.
To conclude, this blog offers up some ideas for how to think about sucessional change in natural ecosystem - what it looks like when it is graphed, and some of the mechanisms that might be used to explain the humps in that graph over time. In permaculture we try to use this knowledge to accelerate successional change in our cultivated systems (e.g., gardens, orchards, forests). Perhaps these concepts might also be useful for thinking about how your products, services, or business might need to evolve over time to become dominant or co-exist successfully in a business ecosystem.
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