To battle or not to battle

Scientists are beginning to think that battling invasive species is a bad idea!

In a recent news article in CBC News, veteran ecologist, Professor Ken Thompson, says humans are panicked about invasive species but this might be a mistake. I found his thoughts to be very interesting. Consider reading the article!

Professor Thompson is a senior research fellow in the Department of Animal and Plant Sciences at the University of Sheffield, England. He thinks that there is good evidence to suggest that the plants and animals we see as “bad” and “invasive” rarely threaten ecosystems. Professor Thompson also believes that fighting against invasive species is doing more harm than the invader itself would have caused.

He released a book called Where Do Camels Belong – Why Invasive Species Aren’t All Bad. He starts by using camels as the perfect example of an invasive species. Camels were evolved in North America but have spread or “invaded” other areas of the world more recently. Professor Thompson speaks about how nature has moved species around throughout history, more frequently now, but it tends to be up for the challenge. Professor Thompson says there is this idea that invasive species drive native species to extinction when they are introduced into areas without predators and diseases as control, but the evidence for this is not very strong. Ecosystems are often already damaged by human activity such as pollution and development so invaders may not be displacing native plants or animals like we think. 

He points out that these ecosystems are often already damaged by human activity. Pollution, over-exploitation of native species, and pressure from development have compromised natural systems. Professor Thompson said, “Most of the time, alien species are simply responding to opportunities that human changes to the environment have created”.

Purple Loosestrife, for example, may not be as damaging as assumed. It has a reputation for crowding out native plant species and taking up their space with tall, colourful stalks and flowers. Professor Thompson says that the plant’s conspicuous nature fooled us. Scientific studies have shown that the Purple Loosestrife actually has little impact on the biodiversity of areas to which it spreads. This plant species may actually provide some benefit by supplying more food for native pollinators.

Professor Thompson does not lack to acknowledge that some species are true damaging invaders! For example, the brown tree snake, annihilated indigenous birds of Guam after being introduced to the Island. He clarifies though, that it is difficult to identify truly damaging invasive species ahead of time because their impact can vary with time as ecosystems evolve and respond.

Our efforts to eradicate invasive species can be very expensive, are rarely successful and often have unintended consequences. Herbicides are a good example. They are used to eliminate invasive plants but can negatively impact native species sprayed by them. Interestingly, Professor Thompson says the invasive species we should worry about most is actually us. Humans have spread to every corner of the world and have largely altered ecosystems.

What he says is completely reasonable! I’ll leave you with 2 very captivating quotes from Professor Ken Thompson that sum up this article…

1. “We’ve chopped down forests, built dams and turned the whole world into a giant cattle pasture, and then we’re surprised that some species quite like what we’ve done. We shouldn’t be surprised”

2. “The cure, in some of these cases, is worse than the disease”

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