INVADERS FROM THE EAST

Rex Burress

“Giant African Snails seized at Los Angeles airport.” Thus stated a news item telling about 67 prohibited African snails being confiscated at the L.A. Airport. They are banned because they are eight inches long and will eat any kind of crop, and possibly spread disease.

Three African Snails were smuggled into Miami in 1966, turned loose in a garden, and within seven years 18,000 were collected! It took ten more years and one million dollars to eradicate them. Most of the edible common garden snails are introduced species

In 2016, a headliner was “Mudsnail found in Feather River!” The tiny invertebrate is from New Zealand and extremely prolific and invasive. Chalk up one more successful invader.

When I worked at the Oakland Nature Center, the airport security gave us some outlandish nature contraband to use for educational purposes. Much of it was taxidermy involving clawed frogs from Africa, and skins of all types. There is also traffic in rare live reptiles, cactus, birds, and mammals smuggled from afar! It is amazing what people spread illegally around the world for profit!

Once upon a time, it is theorized that the land mass of Earth was all connected in a unit called “Gondwana,” and geology was jammed together by tectonic plates colliding about 500 million years ago [mya]. Evolving life-forms developed throughout this super-continent, and spread to what became other continents in following ages. The prehistoric life dramas can be traced through fossils.

It is staggering to consider those vast spans of time when all kinds of physical transactions occurred. The converged land masses of Gondwana broke apart about 100 mya, taking prevailing species with it, diverging into separated continents where evolution went on separate paths. Thus not only small snails evolved into Giant African Land Snails, but thousands of plant species became different than North American flora.

As new species evolved, each earth-arena developed a new cast of biological entities, so that Giant African Land Snails appeared on the African continent, while different species evolved in North America.

Biodiversity is another mysterious development, yet millions of species have appeared and millions disappeared, especially at the end of the Permian Period about 251 mya when it is thought about 90% of species became extinct, according to the book “Prehistoric Life.” There is some speculation that a sixth mass extinction is at hand, with man's activities accelerating a case of 'climate change”' and habitat destruction.

If you're swamped by statistics, so am I. At best, we can only put together a fragmented picture of the past.

The thrust of all this is that when ships could cross the sea, there began an introduction of plant and animal life to other lands. The species-exchange between continents became more pronounced when faster means of transportation developed, and some of those foreign transplants were quite successful, to the point they became entrenched unfavorably with native flora and fauna, especially in North America. Some American species have been introduced to other countries and became invasive. The world is all mixed up!

Some species were acceptable, while others became overly invasive and threatened the existence of long-striving established species. Most of those accidental or purposeful introductions came from Europe/Asia, so we have hardy stands of European wild oats in America, star thistle, gorse, and thousands of other hitchhiker species.

For instance, among the 2,023-plus vascular plants of Butte County, CA, as compiled by Vernon Oswald in 1986, about 23 percent are not native to the county nor state.

“The snail leaves its trail wherever it goes.” --African proverb