Some of you will be aware that I have recently returned from the World Congress of Herpetology, held at the University of Otago in Dunedin, New Zealand. I shall be blogging about my adventures on the other side of the world over the next couple of weeks so keep an eye out for that! I though the ideal book to read whilst on my flights to Dunedin was Where Do Camels Belong? for the obvious reason that it is all based on invasive and non-native species. This is something that is often on my mind especially when it comes to the midwife toad work I’m involved with around the country. In my opinion, a brilliant book is one that changes your viewpoint on something and this book certainly does this! I’d recommend reading it in quick succession to Chris Thomas’ Inheritors of the Earth that I previously reviewed here.

Ken Thompson certainly has a host of credentials that make him the suitable author for this book. All you have to do is type his name into Google or Google Scholar and a myriad of relevant information on his work with non-native and invasive species can be found. One of the most fascinating points Thompson makes in this book is the fact that as a society we have no fixed definition of what makes a species native. This also changes between countries and species groups within that country. Fluffy and charismatic animals tend to the be the ones where this uncertainty is most prevalent. Native species in the UK are those generally classified to have been present before it became an island but without a DeLorean, we can’t exactly be sure for some species as we lack fossil evidence.

One species caught up in this mess is the pool frog (Pelophylax lessonae), which is the subject of a successful reintroduction program. I’m not going to knock another species of amphibian being added to depauperate British herpetofauna. What I cam confused about is why southern clade frogs are seen as alien and have no protection, whilst northern clade frogs (including those reintroduced from Sweden) are seen as native and are protected. They’re all the same species so why aren’t they treated the same? As I’m sure you can probably tell, it’s complicated and this is something that Thompson repeats throughout his book.

The book itself is highly readable and takes the reader on an ecological tour of how some species have become public enemies despite a lack of any evidence to suggest so. Another message that is repeated throughout the book is how invasive species are often better adapted to human disturbed habitats that their native counterparts and so thrive in a world where we have irreversibly altered the planet. Instead of addressing these issues, we use the species as a scapegoat sometimes investing millions of dollars to eradicate it, only for those projects to fail. Imagine how much it would cost to eradicate grey squirrels from the UK or cane toads from Australia? We’re past the point of no return and it just isn’t viable. Going back to Thomas’ book, Thompson also shows how many invasive species actually improve species diversity. Now this isn’t exactly linked to Thomas’ any net increase in biodiversity is good policy, but instead demonstrates how some species help create food and a refuge for other species.

As we all know, correlation doesn’t mean causation and Thompson really drills this home. There are of course a few descriptions of some invasions that have gone horribly wrong such as Guam and Hawaii but there is also hope. In some locations, endangered species that have been moved outside of their native range (and by most definitions are therefore invasive), have been able to hold on, finding a niche that was previously unoccupied. Is this a bid thing? Well I think we need to look at the whole world as an Ark. As habitat loss and climate change ramp up, we’re going to need to move species around via assisted colonisation otherwise their currently habitat will become less viable and the species may become extinct. However this is unlikely to happen anytime soon at the landscape/ecosystem level but for now, some species may become ecological refugees unless we move them to new areas that are assessed to be suitable for them.

The book is thoroughly thought provoking and I urge anyone working in ecology, invasion biology or disease ecology to take the time to read the book. I guarantee it will change your viewpoint on a number of species and may even make you reconsider why it is you are doing what you do.