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Afrikaanse Inligting
Recruiting Plants from other Regions?
A suggestion
If the climate of the region changes is set to change so significantly
should we not be considering recruiting plants from other regions to
bolster our biodiversity and researching alternative suitable homes for
our Cape plants in South America or somewhere? In fact should we not
be thinking of a global plant travel and relocation policy, testing
to see which rare plants might survive elsewhere, find suitable
pollinators etc.
I find it ironic that in a world where people are allowed to travel freely
and globalization is encouraged, we are now trying to restrict the
movement of plants. Surely the survival of many species is going to
be based on their ability to move as climate changes and we should be
looking at this globally and trying to help them along, rather than
whacking any alien that shows its head. While I do acknowledge that
some aliens are grossly greedy and need controlling while there is
still a chance for other plants to occpy that space, I think we are
becoming overly obssessed with the notion of indigenous at all costs.
These are after all geographic boundaries which are impossed by man and
plants have been moving about the world with men for many centuries.
I think there is a term in Britain for species which arrived there before
1500 and they are now very concerned as some of them are also threatened.
Man has been a good disperal agent and now that he has mucked up the
climate, instead of wringing his hands and trying to put the clock back to
some idyllic , pristine age when all plants knew their places, man had
better become a better disperal agent and try to find everything a new
home on the planet where it will thrive.
To recap. I think if many species are to survive the changes that
lie ahead they are going to have to move and travel maybe far from their
original homelands and we should start looking at what needs to be to
ensure the survival of current Cape plants from that perspective.
Can we model which parts of the world they would thrive in infuture- Can
we try setting up trial plantings there?
We should also perhaps acknowlege that the plants which will thrive
at the Cape in future might be very different to our current lot and so we
should perhaps be testing a range of alien plants to see which will
support the fauna of the region which might not move off with the plants.
Yvonne Reynolds 16/05/05
Response from the Protea Atlas Office
The answer to your question is quite simple:
All species come with baggage: predators, pollinators, pests, fungal
pathogens, fungal mycorrhiza, seed dispersers and so forth.
Furthermore, most species can only cope with a small range of ecologies,
based on climate, soils, fire ecology and so forth.
Most introductions outside of home ranges fail because they are taken to
the wrong habitat. Of course, keen gardeners can look after
anything, but these plants would not stand a chance outside of carefully
managed gardens.
Where the introduction is to a suitable ecology, most fail because their
essential symbionts are absent.
Of those that survive, a small proportion fit in well, being able to use
other symbionts and thus thrive. Not having any pathogens or
predators, these go wild and become major pests.
Even the introduction of plant or animal species that will not go wild is
fraught with problems, in that its symbionts - some of which might be
pathogenic to other organisms - may run amok if inadvertently introduced
with the host.
So the answer to your question is simple. The danger of a plant
going wild, and its costs in terms of ecosystem services lost and
subsequent control mean that we must quarantine high potential invasives
out of all susceptable ecosystems.
The possibility of establishing rare species outside of their natural
ranges is low and does not justify the cost and effort.
Climate change is going to put all natural ecosystems under stress. During
this period they will be particularly vulnerable to invasions, and the
most suitable strategy is to minimize all stresses. Bringing in
aliens is absurd. Even moving species within the Fynbos Biome is
fraught with problems - the first and foremost is to ensure that the
species you move in does not hybridize with its relatives already there.
And secondly, ensuring that it will not compete directly with its
relatives and thus exacerbate the stresses in an already stressed system.
The only loose end is the old introduced plants that they are trying to
conserve inthe UK (and Europe). Follow up the details and you will
discover that these are species of cultivation, and rely on cultivation,
furthermore on old-style cultivation (no herbicides, shallow ploughing,
hedgerows and inefficient harvesting). These plants do not occur in the
wild and the only way to conserve them is in agricultural systems, hence
the need to pay farmers to maintain subeconomical farming practices.
This works well when you only have 2000 plant species, of which a quarter
are weeds. However, in the Cape with 9000 plant species natural and
many more introduced, such luxuries are beyond our conservation budgets.
I trust that as you give more thought to the matter, you will soon realize
that what you are suggesting is not an option, but on the contrary, must
not be allowed at all costs. Conservation cannot be achieved by
propagating invasive alien weeds that will aggravate the conservation
plight of threatened species in underfunded and underresourced
conservation areas.
What will happen can be seen in the bird-world: flocks of Eurasian
Starlings, Mynas, House Crows, and Eurasian Sparrows are worldwide
impacting local birds. Plant-wise we will also end up with a handful
of cosmopolitan weeds threatening thousands of plants. Some
ecosystems are particularly sensitive to such invaders - the Cape Flora
appears to be one. Such systems should be especially carefully
protected from unwise translocations.
Tony Rebelo
May 2005
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