Purple Loosestrife not so bad after all

Sunday, March 8, 2015

Twenty years ago, non-native Purple Loosestrife was expected to take over wetlands in southern Ontario and overwhelm biodiversity. It didn't happen and Prof. Ken Thompson, a senior research fellow in the Department of Animal and Plant Sciences at the University of Sheffield in England, says that is typical. He argues that invasive species do not pose as great a risk as many say they do, the CBC reports.

In an interview with the CBC, Thompson – author of "Where Do Camels Belong - Why Invasive Species Aren't All Bad" – argues that many alien species are rarely a true threat to the native ecosystems they join. So-called "invasive" species are often just taking advantage of the damage caused by human activity and pollution. In an article for the Huffington Post, Thompson wrote that "if we think we have reason to dislike a species – native or alien – we should first check if it is actually causing net harm, and specifically if the species itself is the problem and not merely a symptom of some other problem."

According to Thompson, Purple Loosestrife may in fact be providing more food for native pollinators. Thompson does admit that some species – such as the Brown Tree Snake which destroyed the native bird population of Guam – are a true risk to an ecosystem, but that measures taken by humans against invasive species often have unintentional, long-lasting and harmful consequences on the environment. BF