The action begins on a gusty afternoon in late September in Tetbury, Gloucestershire. Bee Inspectors’ efforts to track down the source of local sightings of Asian Hornets have resulted in the discovery of a nest. A zero-tolerance approach to one alien invader with the capacity to wipe out native bees and wasps and devastate honeybees has paid off. Eatherley’s prologue, A Hornet’s Nest, sets the scene for a long history of alien invasions, some disastrous, others useful. The unfolding story of invasive aliens is interspersed with vivid scenes like this, often involving combat between conservationist and alien.
The first invaders he describes are humans; alongside us come our fellow-travellers, including a bunch of annual weeds of cultivated land, invertebrates such as the grease moth or tabby, and mammals such as House Mouse and another tabby, the wildcat descendant employed as a mouse-catcher before being invited indoors. This historical tour continues with what the Romans and Normans did for us by way of introductions, and how European exploration of the world from the late medieval period onwards brought new species home, and took our own natives abroad. The legacy of Britain’s plant-hunters begins with a trek down a Devon stream, pulling Himalayan Balsam up by the roots. Invertebrate hitchhikers, fur-farm escapees and freshwater invaders all come under the spotlight. Until I read the chapter on aliens beneath the waves I had no idea how much trouble there was at sea.
The penultimate chapter catalogues some of the hair-raising mistakes which have been made in the name of biological control. Fortunately, most of these are historic, but their scale and cost are truly shocking. Where the motive is to find a cost-effective solution to deal with a damaging agricultural and forestry pest, ecology and caution are inclined to take a back seat. It is not uncommon for the biological control to get out of control.
There are some omissions, such as the absence of any mention of our own Cordgrass Spartina anglica which appeared 150 years ago in Southampton Water. Once planted to prevent coastal erosion, in my early conservation days it had become enemy number one, the Himalayan Balsam of its time. Parties of conservationists traipsed across mudflats, pulling it up. Now that it has faded away here, its ability to trap silt is sometimes missed. It is causing serious problems on Australasian shores, but in time it may fade from those mudflats, too. It tells a nuanced, complicated story which would have suited Eatherley well. The explanation may be that he is not entirely at home with plants; it is hard to be knowledgeable about everything.
That said, Eatherley has researched his subject well, and the many and varied theories about what turns an innocent species into an invading monster all get a hearing. Common names used throughout the text do not always pinpoint the species involved, so it is of great help to have at the end a species index, along with a general index. To sum up, Eatherley’s thorough digest of a complex subject is engaging, informative and balanced. It is the first of these which most explains why Invasive Aliens has garnered such a sheaf of book awards. If the journalistic style puts off a few readers, it will please many more because the subject has been presented with verve and panache; I did not expect to be drawn in so comprehensively or to learn so much.
As for balance, I expected Eatherley to stoke up what is becoming a polarised debate about introductions in the wake of Fred Pearce’s The New Wild. This glories in aliens as vehicles for dynamism which help nature to regenerate. I also expected that he would deploy half-truths – like half-bricks, journalists use them because they carry farther. He does no such thing. He presents the evidence and hands over to the reader to draw conclusions. In his final chapter, looking to the future, the note which he strikes is one of realism. That we are fighting a losing battle with most invasive species is a statement of fact, and the invasive species most responsible is, of course, ourselves. The impact of invasives can be severe. Technology is opening up new means of tackling problem species, but prevention and early detection are the best hope. Yet few species are actually damaging and some can have benefits. We should pick our battles carefully and avoid knee-jerk attitudes in either direction. We should encourage as many people as possible to understand this important issue. Reading this book is a very good place to start.