I have been inspired to write this after reading the very interesting post from Jorge Palmeirim (Dept. Biologia Animal/Centro de Biologia Ambiental Faculdade de Ciencias, Universidade de Lisboa, Lisbon, Portugal) on research priorities concerning invasive species on islands, amongst other things. This is not a direct comment on the content of Jorge's posting, but more of a question or an invitation for comments.

Jorge mentions the case of some Macaronesian islands with patches of highly valuable native vegetation that need to be protected from invasive alien species. My question is how does one achieve this when there is little or no control of what is brought to the islands in the way of alien species that are potentially invasive if they are deliberately or accidentally released?

What has spurred this line of thought is the fact that my own country, Malta, is experiencing this very problem now that it has become a member of the European Union. Malta does not have as rich a biodiversity as do the Macaronesian islands, but it does have its own suite of scientifically interesting native species including island endemics. These are under threat from invasive alien species as are other islands biotas elsewhere. Before entry into the European Union, Malta operated a system of controls on the import of alien species whereby the importer had to apply for a permit to import BEFORE the actual importation took place. These permits were refused if the species was a known invasive in habitats similar to those that occur in the Maltese islands or if there was the danger that the species in question would negatively affect local biodiversity if it escaped or was released into the wild (applying the precautionary principle).

After 1st May, borders no longer existed between Malta and the rest of the EU and under the requirement of free trade anybody could bring in almost anything from any other EU member state. The system of requiring permits before transporting alien species to Malta was abolished. The result is that in the past few months there has been an influx of all manner of alien species into local garden centres, aquarium shops and petshops and many more have been 'imported' by private individuals - these species include know invasives in Mediterranean ecosystems.

No know escapes have occurred so far, but very little time has passed and predicting that such an escape or release followed by establishment of an alien population in the wild is a pretty safe bet.

So again, how does one guard island biodiversity from alien invasive species under the 'free trade regime' operating in the European Union? How do existing EU member states guard their island biodiversity in this regard?

Perhaps one research priority can be the impact of existing management regimes on island biodiversity!

Patrick Schembri
Department of Biology
University of Malta
Msida MSD 06
MALTA