Getting a balanced view

[Beatriz]

Those who read “Where do Camels Belong” should also read “Invasive Species” by Daniel Simberloff to take a balanced perspective. Thompson misunderstands and misrepresents the works and writings about invasive species. Nobody wants to return to a “frozen moment.” We all know that evolution goes on unstoppable and that biotas also keep changing with time. The most that we can aspire to is to restore the estimated trajectory the ecosystem would have followed before being disrupted by species introductions.

Ken Thompson debunks some myths of his own creation. It is easy to debunk myths created for that whole purpose. Nobody believes that “Aliens are out to get us” or that “Aliens are bad, natives good.” For instance, those who study the invasive brown snake call it “handsome and sleek” and regard it as a “regrettably translocated species, not a demon from ecological hell.” No, invasive species are not bad, evil or any of the other emotionally laden terms Thompson uses repeatedly.

His examples of beneficial invasive species are unconvincing. It is not enough to show that some native species benefit from the introduction. You must look at the totality of interactions with the rest of the biotic community. Newly arrived species require many thousands of years to become fully integrated with the rest of the biota. He never considered this notion.

He lists some examples of disastrous attempts to control invasive species. This was true of some earlier attempts. However there are many other examples of successful eradications or control, and the list of successes keeps growing. He should present a balanced list.

It is not a matter of favoring some native species over some introduced ones. Unfortunately he doesn't grasp the larger issue, invasions cause serious impacts on ecosystem diversity and processes. If we continue transporting species at the present rate, the entire globe would become a second Pangaea which couldn't support the present biodiversity.

Most reviewers don't understand what an invasive species is. They assume that invasive is the opposite of native. Not so, only a small number of non-native species become established and an even smaller number invade. This shows the failure of the book to explain what we understand for invasive. How can you write an entire book on invasions not making clear what you are talking about to the point that the readers don't get it? Yes, species have been on the move from the beginning of life. However, the numbers of species that move beyond geographic barriers and invade other territories on their own are minuscule. This doesn't compare with the huge numbers of species (several orders of magnitude larger) moved by humans in recent centuries. This is why we need to talk about human caused invasions.

The biggest trouble with this book is that it conveys the idea that invasive species are OK. It reassures people to go on moving species and producing new invasions. This is extremely irresponsible because the best measure against invasions and their consequences is prevention. PREVENTION!