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Introduced organisms or invading species?

Date: 17.8.2009 

One of environmental risks referred with genetically modified organisms is impair of biodiversity. Such statement is included in the Convention on Biological Diversity (CBD) as well as in the Cartagena Protocol. It has never been explained why particularly GMO are introducing such risk. How, for example, Bt maize can impair the biodiversity of central Europe. Or RoundupReady soy beans the biodiversity of Illinois.

On the other hand radiation mutant of rice expressing tolerance to salt has been introduced in thousands of hectares in Asia without any concerns by CBD. It can invade halophillic biotopes, but nobody cares.

Opponents of GMO claim that GM crops will replaced traditional local varieties. However the history of agriculture and selection of crops consists in stepvise improving the crop performance that means replacing existing variety by a new one giving higher yield or exhibiting better resistance to pests or diseases.

What is the danger to biodiversity and where it comes from?

The damage to biodiversity may be seen in the reduction of the spectrum of species or varieties at given region. There are many factors that may cause such effect. Let us focus on one of them that could be in some connection with GMO - the introduction of an organism that is foreign for given region. If the invader is more competitive than local organisms in similar niche it may, after certain time, replace them.

An example may be the introduction of locust-tree in our country. It replaced oaks (Quercus pubescens) on warm and relatively dry hillsides. Globally there are many more examples. However, the introduction of new organism may cause also the opposite - the increase of the number of species without suppressing the native ones in given region. But this is often felt as unwelcome, usually because it interferes with human interests.

Such introduction may be deliberate, by accident or totally independent on human activity. Rabbit in Australia is very popular example of the first case. It is less known that carp in Australian rivers is also "weed-fish". Domestic animals were introduced in different natural habitants causing serious damage to local society of organisms.

Many pests and weeds were transferred by accident between continents. Gallant soldier (Galinsoga parviflora) is well known weed to all gardeners in our country. It came from Peru. After maize reached large-scale planting in Europe it provided optimal host for the reproduction of a little moth - Ostrinia nubilalis, which became specific pest in maize. Later by accident it was transferred to American continent - and turned into serious pest called there european corn borer. The American continent paid back: in 1992 a little beetle as a dead-head in a plane reached the airport in Beograd. It found the new habitant pleasant and start to colonize it. Recently it has arrived to Czech Republic and we are faced with new pest of maize - root worm Diabrotica.

Why we discussed these well known stories right now? There are two reasons for this. In Brussels the discussion starts how to combat invading organisms by bureaucratic steps. It is very difficult to find rational approach and the EU regulation of GMO must warn us. Nobody can say in advance that, e.g., certain decorative plant can turn into difficult weed in Europe. We may remember the history of japanese knotweed (Reynoutria japonica) that was brought to gardens in England as a decorative exotic plant and now is troubling almost whole Europe. Being upset by weeding gallant soldier in our garden should we take legal steps to eliminate species transferred, e.g. from Peru? We have to be careful: there is another species transferred from that region Solanum tuberosum - potato!
On the other hand biofuel is now politically popular. Burning wheat in power plants, some time ago celebrated as green achievement, is out off fashion in these days. Green laws ask agriculture for s.c. "energetic plants" and companies and farmers are looking for best candidates. In fact japanese knotweed is one of them, but there are more. Certain hybrids of docks are grown in our country and farmers are pleased with the encouragement by law supporting biofuels. Some of these hybrids originated in Ukraine or Russia. There are no concerns by environmentalists who are so much afraid that Bt maize will damage the biodiversity of our country.

We come to the conclusion that the topic of "invading species" is again one of the political issues and we have to ask our representatives in EU bodies to follow science rather than ideology.

Author: Prof. Jaroslav Drobník




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