Date: 30 August 2002
Subject: Pest Control

As a species we not only affect the environment but are aware of doing so. One way I which we have affected in particular island ecologies is through introducing alien species. Actually I quite enjoy having "alien" grey squirrels in my back garden – but also in seeing our native red ones in nearby Formby where they still live.

A year or so ago it was estimated that only about 160,000 red squirrels were left in the UK, compared to 2.5 million grey squirrels. A system of "safe havens" for red was established (cf http://www.ananova.com/news/story/sm_423195.html), which does seem to have had some positive effect. Red squirrels, of course, are fluffy and photogenic – and children can be urged (eg by the Dorset Wildlife Trust) to "adopt" a red squirrel.

Havoc can be brought by alien species which may be quite unlike native ones. On the Galapagos islands (made famous by Charles Darwin) there are some 500"introduced" species, and feral goats have become a particular problem because they take vegetation liked by the famous giant tortoises. In 1959, Ecuador declared all uninhabited areas in the Galapagos to be a National Park – and are trying to exterminate the goats in some islands. Goats are large enough to see and eliminate once one finds them, and one method used to do so is a "judas goat". Since goats are sociable, a "judas goat" with a tracking device can locate feral goats more easily than a human could. It may seem hard on the poor goats, but the alternative is extinction for native species and unease is largely emotional.

There may be more fundamental unease at the solution to the control of another alien first reported in Galapagos in 1997: the cottony cushion scale. In January 2002 a natural enemy of the cottony cushion scale, the Australian ladybird ("ladybug" to some countries), was released by scientists. This followed extensive studies to try to ensure this new predator species posed no threat to the Galapagos ecosystem. But can we be sure?

Most of us find ladybirds unthreatening, but biological methods used to attempt to control the rabbits introduced first in 1859 into Australia may raise more concerns. Not very humane human introduced lethal sicknesses in the form of rabbit viruses like myxomatosis and calicvirus have been used in the past – though not even all that effectively since rabbits develop resistance and less lethal strains of the virus become more common. The more recent method is a kind of human introduced birth control for bunnies. This involves adding new genetic information to a strain of the myxoma virus. The modified virus will cause only a brief non-threatening fever, and so it should spread easily amongst bunnies and make them infertile (cf eg http://genetech.csiro.au/research/environment/rabbit_doc_long.htm). This month (10th August) the New Scientist reported that since May 2002 this project has been meeting success, and that release of the virus is now sought.

Should Christians be concerned? Are we now "playing God"? The problem is that humans first caused the threat to native species by introducing alien ones. The native Galapagos or Australian species cannot form a committee to deal with it – only we as conscious agents may be able to avert extinction. No means of doing this is perfect, because we are in a non-ideal situation. So we have a dilemma. On the one hand nothing should be done without proper consideration – eg whether a virus could jump species or infect other countries where rabbits are native and not a threat. On the other hand if we think about it for too long the damage may already have been done. There can be no simple or jingoistic answers.