Imagine if universal truths were subverted. Up was down, right was left, day was night, and non-native species were good.

The last switch is exactly what Fred Pearce aims to do in his book The New Wild: Why Invasive Species Will Be Nature’s Salvation. He wants to convince people that non-native species do not deserve their negative reputation.

Pearce, a U.K.-based author and environmental journalist, challenges many of the typically held tenets of ecology and conservation. Using many examples of non-native plants and animals that do not harm their environment, he outlines why these beliefs need to be reconsidered in order to better support the changing natural world.

One of his most interesting points about invasive species is that they are able to spread so quickly in a new environment not because they are pushing out native species but because humans have created ideal habitats for them to thrive through environmental degradation, such as polluting waterways or abandoning factories. Pearce argues that invasive species are not the villains. They are simply acting as they are naturally meant to. It is human actions that underlie invasive species’ harms.

Water hyacinth (Source: Diogo Matias)

Water hyacinth in Lake Victoria is one example of this. In 1998, the plant covered four-fifths of Uganda’s shore. Fishermen removed patches six feet thick in Kisumu, Kenya. The coverage made it difficult for fishing boats to move through the lake, sometimes taking five hours to dock. It created public health dangers as well, namely breeding grounds for disease-carrying mosquitoes and hiding spots for crocodiles and hippos. Eight people from a nearby village had been killed by these large animals within two years.

At first glance, this looks a lot like a classic example of an invasive species rapidly spreading through a new ecosystem. But, the real problem, Pearce shows, is that Lake Victoria had become polluted. 

Water hyacinth is known to “[feed] hungrily on nutrient pollution from sewage and farm runoff,” he explains, so once Lake Victoria became filled with pollution, the water hyacinth followed.

This example helps explain Pearce’s frustration with the traditional assumption that non-native species are the root of the problem. Not only did this assumption give water hyacinth a bad reputation, it also kept the real cause — nutrient pollution — from being addressed.

Seeing invasive species successfully adapt to a world that is rapidly changing due to human influence is encouraging. Pearce argues invasives can help keep non-human species around as humans make it more and more difficult for them to survive. Instead of conservationists working to keep non-natives out of new ecosystems, they should be working to facilitate their survival. This is the “new wild” Pearce references in his title.

Although Pearce tries to destigmatize invasive species, he acknowledges that there are invasive species that do cause big problems. Both human related, like public health dangers, and non-human related, like crowding out of native shrubs. What he is actually arguing is that not all non-native species are invasive and those that are aren’t as problematic as they are often portrayed to be.

While I appreciated this recognition and agree with his general argument, Pearce makes broad claims surrounding it that have questionable implications. For example, he mentions a couple of invasive species — such as tamarisk and Himalayan balsam — that did not turn out to be very harmful. From this, he suggests people should “learn a little tolerance” for non-natives and essentially let them run wild. I am wary of this because, often, the species he looked at had taken decades to show they were not a problem. What if people waited to address a seemingly problematic species and it turned out to actually be harmful? The species and the problems it causes would be even harder to eradicate.

Something Pearce is heavily critical of is the “shaky foundation” much of the widely cited data about invasives and their impacts on native species and their economic damages is based on. He accuses invasion biologists (biologists dedicated to studying invasive species) of having a selection bias towards non-native species that are known to cause harm. But Pearce may be just as guilty of bias, only in the opposite direction. He largely favors examples that show non-native species that are not harmful.

Despite these limitations, keeping Pearce’s argument in mind when approaching invasive species solutions can be useful. It should encourage more research on invasives, both as a collection and as individual species. By completing further research, invasive species specialists can learn whether or not a species is actually a threat and, if it is, how it can best be dealt with, or, if it is not, what the actual cause of the problem is.

Going into the book, I was skeptical of the arguments Pearce advances. How could so much of what I was familiar with be incorrect (or at least partially so)? But, Pearce’s analysis made me think more deeply about how our assumptions about the natural environment and human’s relationship with it can actually get in the way of solving some of the most pressing problems related to Earth’s health in the future.