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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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