Several examples of the uncontrolled spread of genetically engineered plants into wild populations and ecosystems have been documented: cotton in Mexico, oilseed rape in North America, Japan, Switzerland and Australia and grasses in the USA. There are also cases of repeated transgene presence in landraces or local varieties of crop plants such as maize in Mexico and rice in China. This increasing trend towards uncontrolled spread of transgenes into wild populations and ecosystems raises a high level of concern for the release of new organisms such as genetically engineered trees, fish and insects and the challenges posed by emerging applications of synthetic biology.
Genetic engineering and synthetic biology represent a radical break from widely recognized natural restrictions on genome regulation and interspecies genetic exchange. Maintaining the ability of organisms to develop under their evolved dispositions and naturally established restrictions and to participate in further evolutionary processes is a crucial aspect of the protection of biodiversity. In the same way that we seek to protect organisms and ecosystems from persistent chemical substances, we should also protect them from the uncontrolled spread of synthetic and genetically engineered organisms. In the short or long term, these organisms have a capacity to self-replicate, evolve and interact with other organisms in unpredictable ways and thereby represent a threat to ecological systems and their resilience.
There is a risk that we will not be able to recover the original biodiversity, as the dynamics of wild and cultivated native varieties will be altered. We cannot rely solely on gene banks, as they are able to preserve only a very small percentage of the genetic diversity present within centres of origin and of genetic diversity.
From a regulatory point of view, spatio-temporal control of genetically engineered organisms is necessary. It is a fundamental precondition for any risk assessment because no reliable predictions can be made concerning the consequences of artificially transformed organisms once they are released or escape into wider environments and become part of open-ended evolutionary processes.
Article 17 of the Cartagena Protocol on Biosafety requires Parties to prevent or minimize the risks of unintentional transboundary movements of genetically engineered organisms. The current trend of an increasing spread of these organisms outside of the managed settings for which they were approved threatens to enhance the potential for unintentional transboundary movements. Finally, the precautionary principle can only be implemented if genetically engineered organisms can be retrieved from the environment in case of emergency. This becomes impossible once transgenes move and accumulate in wild and landrace varieties.
While all genetically engineered organisms can pose risks to the environment and health, we particularly call for the prohibition of experimental releases, imports and commercialization of genetically engineered organisms if:

1. they can persist and invade the environment if they escape their containment.
2. they can not be withdrawn from the environment if this is required.
3. it is already known that they can persist or have invasive behavior after release into the environment.
4. their release may lead to transgene flow into populations of local varieties at centres of origin and of genetic diversity and the accumulation of transgenes in the genomes of native varieties.