There’s a deeper problem, too, in our attitude towards aliens. Moreover, much of the cost of the invaders turns out to be the money spent controlling them. For one thing, says Thompson, hardly anyone bothers to count the economic benefits of “aliens” such as wheat and cows – a sum that runs to $800 billion per year in the US alone. Nor are introduced species the financial burden they are often made out to be. Even in Hawaii – poster child for the noxious effects of alien species – invaders tend to make ecosystems more diverse, not less. But when ecologists looked closer, reports Thompson, there was little evidence of actual harm. Purple loosestrife, for example, is often viewed as one of the worst invasive weeds in North America because it forms dense stands of tall, conspicuous flowering heads. In Where Do Camels Belong? The story and science of invasive species, plant biologist Ken Thompson argues that most alien species – even some topping the eco-horror lists – cause little or no lasting damage and aren’t worth the angst, effort or money we devote to controlling them. He discusses, too, whether our fears could be getting in the way of conserving biodiversity, and responding to the threat of climate change.Not so fast. But do we need to fear invaders? And indeed, can we control them, and do we choose the right targets? Ken Thompson puts forward a fascinating array of narratives to explore what he sees as the crucial question - why only a minority of introduced species succeed, and why so few of them go on to cause trouble.
We have all heard the horror stories of invasives, from Japanese knotweed that puts fear into the heart of gardeners to brown tree snakes that have taken over the island of Guam. This is a classic example of the contradictions of 'native' and 'invasive' species, a hot issue right now, as the flip-side of biodiversity. They evolved in North America, retain their greatest diversity in South America, and the only remaining wild dromedaries are in Australia. Where do camels belong? In the Arab world may seem the obvious answer, but they are relative newcomers there. Print Where Do Camels Belong? - The story and science of invasive species
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