Biosecurity: the first mention

The following is the first ever mention of biosecurity (or bio-security) in a UK newspaper. It appeared in the Scotsman on July 1st 1996 and was written by Fred Pearce.  


The aliens have landed

  Fred Pearce

THEY call them genetic stowaways and biological aliens. You probably have some in your garden. Scotland certainly has some of the most fabulous collections in the world in its great west coast temperate and sub-tropical gardens, at Inverewe, Lochalsh and elsewhere - alien species from New Zealand, China, the Himalayas and the Americas, lovingly collected by generations of botanists.

Amid all the talk of a crisis for the planet's biodiversity, some countries, Scotland included, "probably have far more species now than ever before," Jeffrey McNeely of the World Conservation Union told a conference on alien species today. But are they friend or foe, these biological interlopers? Should we embrace their bright colours and strange ways, or fear them? After extolling the virtues of the worldwide trade in ornamental plants in increasing local biological diversity, McNeely went on to warn the meeting, at Trondheim in Norway, that "the spread of alien species" is also "a threat to global biodiversity." In biology today, insularity and fear of the unknown is taking hold. "Most alien species turn out to be pests," said another speaker.

The downside to introduced biological diversity lies in the risk that aliens can pose to local species, espe-cially the rare species and "endemics" that are found nowhere else on earth. A simple British example is the red squirrel. The introduction of the grey squirrel increased British biodiversity, but it is now driving the red squirrel north and is one day likely to run it off the islands altogether. Scotland cannot hold out forever.

There are hundreds of similar examples of aliens driving out the indigenous. Of plants, animals, insects and microbes breaking out from one continent, or even a small island, and conquering new territories, causing genetic rape and pillage as they go. Whether carried deliberately by humans - as with ornaments or new crops, for instance - or hitchhiking aboard ships and planes; as parasites on other species or swimming up newly dug canals, the aliens are on the march, often with catastrophic results.

In the past two years the pink mealybug, a beast never before seen in the western hemisphere, has been destroying vegetation and crops in the Caribbean, starting in Grenada.

Some say it arrived in a diplomatic bag from a Far East nation, where it has happily existed for millennia without mishap. But in the Caribbean, where the pink mealybug has no predators, it has run wild, eating teak trees and hibiscus and stripping cocoa plantations.

British biologists this year sent for a Asian wasp to try to control the invader.

Peter Moyle of the University of California at Davis calls this "the Frankenstein effect" - the unpredictable and potentially devastating impact of apparently benign or invisible invaders. And aliens don't come much more devastating than Mnemiopsis leidyi, a jellyfish they now call "the blob that ate the Black Sea." It reached the sea in 1981 as a stowaway in a ship's ballast water from America, where it had never caused anyone any harm. In the Black Sea, it encountered no predators but plenty of food.

It munched its way through the eggs and larvae of numerous Black Sea fish, causing a 90 per cent drop in the sea's fish catches within six years. Sometimes the invasion is a deliberate act of man. The jury is still out on one of the greatest alien species experiments: the deliberate introduction in the Fifties of the Nile perch into east Africa's Lake Victoria, the world's second largest lake. It has not served biodiversity too well. Before the Nile perch was introduced, the lake had more than 300 fish species known as haplchromines, which are found nowhere else on earth. Today "some 200 are feared to have become extinct", Richard Ogulu-Ohwayo of Uganda's National Agricultural Research Organisation told the meeting.

The haplchromines once ate the lake's algae. Now the lake is filling with rotting algae, which is consuming its oxygen. Ecologists are up in arms, but the 30 million people who rely on the lake for their fish are happy. For now at least, catches are high and the Nile perch is the best catch of them all.

One of the biggest accidental introductions of alien fish followed the opening of the Suez canal linking the Red Sea and Mediterranean in 1869.

Nearly 300 species have moved from the Indian Ocean into the Mediterranean, according to Charles Bou-douresque of the University of the Mediterranean in Marseilles.

And more come every year, though curiously few species have gone in the opposite direction. "Off the Israeli coast," he says, "migrant fish now constitute a third of trawl catches."

One species that probably did not arrive via the Suez canal is a sea grass called Caulerpa taxifolia.

Nobody is admitting how it got from its Indian Ocean home to the Riviera, where its dense green mats just below low-water mark began to displace native sea grasses from the mid-Eighties. But it first appeared just outside the giant aquarium once run by Jacques Cousteau in Monaco.

Out of the way islands often suffer the worst from species invasions. Hawaii takes in more than 20 new insect species alone every year -roughly a million times the natural inva-sion rate for these remote Pacific islands. "Half of these alien invertebrates are known pests," says Alan Holt of the Nature Conservancy of Hawaii, and they are threatening the plethora of endemic Hawaiian species. Invaders so far held at bay by strict quarantine laws include poisonous snakes and biting insects such as midges and mosquitoes - but for how much longer? Island outposts of the British empire suffered especially, as sailors brought new animals along for food.

Goats ate the forests of St Helena, while cats ate the birds. And ships' rats have done the same from the Caribbean to the South Pacific. It may have been hunters that saw off Mauritius's most famous lost species, the flightless dodo bird. But in this "ecological disaster zone", says Wendy Strahm from the World Conservation Union, there are more alien plant species growing today than native species.

Even the biggest islands suffer.

After tens of millions of years of biological isolation, the landscape of Australia has been "transformed over the last 200 years" by new species, says Roger Pech, an Australian government biologist.

Rabbits, foxes and the house mouse from Europe have led the way. In New Zealand, according to Michael Clout of the University of Auckland, the most important issue in conservation "is the management of invasive species" such as the rat. A highlight of the country's legislative programme in 1993 was the passage of the Biosecurity Act to help keep out alien species.

It may be too late, as the globalisation of world trade and the exponential growth of air travel brings more and more species across the world every day. But more countries seem to be trying to raise the biological drawbridge. Alien species are no longer welcome.