Invasive species: vectors and management strategies

Ruiz, G. M. & Carlton, J. T. (eds) 2003 Invasive species: vectors and management strategies. Island Press, Washington DC, USA xiii + 520 pp, figs, tables, maps, index. Hardback: price US 75, ISBN 1-55963-902-4. Paperback: price US40, ISBN 1-55963-903-2. Phase One of the Global Invasive Species Programme (GISP I), which ran over the turn of the century, was not unlike the SCOPE Ecology of Biological Invasions programme in the 1980s. Both were chaired by Hal Mooney of Stanford, both went forward by a series of symposia, some published expeditiously, some less so. The SCOPE programme was almost entirely straight biology while GISP I had much more on human effects, economics, trade and management. This volume is the result of a GISP I symposium held in 1999 and, as the second part of the title indicates, has much on trade and management but also something on diplomacy and on risk assessment. It comes in two parts, each roughly half the book. The first part ‘Invasion causes, routes, and vectors: spatial and temporal patterns in terrestrial, freshwater, and marine ecosystems’ has nine chapters on plants, fungi, insects, terrestrial vertebrates, land and freshwater snails and slugs, aquatic vertebrates in the US, invasions of the coasts of the US, marine plants, and an analysis of shipping to the Great Lakes. To those I would add chapter 12, 60 pages on ‘Vectors and pathways of biological invasions in South Africa — past, present and future’ though that does have a final short section on legislation. As can be seen, these first chapters cover a wide range of organisms and situations but are nevertheless not comprehensive. They tend to be very factual so will be most useful for reference but they are not light reading. Richard Mack's first chapter on plant invasions worldwide is sensibly selective and, I found, considerably more readable than most of the other chapters in the first section. In the other chapters, I often found it difficult to see the wood for the trees and the messages that I did get were a bit platitudinous: for instance that large organisms are usually introduced intentionally, small ones by accident or that pelagic stages are found in ballast, sessile ones on the hull of ships. But I fear I'm being unfair, the detail is what matters. Nevertheless, more analysis in many of the chapters would have been welcome. The second part is more varied and gave me more to think about. There are chapters on invasive species management in both Australia and New Zealand with, appropriately for this symposium, emphasis on preventing invasions. The chapter on mitigating plant pests invading the US also emphasizes prevention. The 20-page chapter by Jamie Reaser and colleagues on ‘Environmental diplomacy and the global movement of invasive alien species: an US perspective’ is excellent on the present situation but doesn't go into what could be done or the suggestions that have been made. The rest of the second part is three chapters on risk assessment. Keith Hayes would like us to move to something more akin to the chemical industries hazard analysis and hazard operability. From my experience of these for genetically modified organisms, I would expect the information on invasions to be insufficient to make them work. Indeed he praises Charles Suckling's GENHAZ which, as far as I know, has been a total disappointment. Hayes reviews, very usefully, past attempts and then summarizes five bullet points that ‘a good bioinvasive risk assessment will have’ but goes on to note ‘few bioinvasive risk assessments exhibit all (or indeed any) of these characteristics’. Richard Orr gives more detail, including the forms, for a particular risk analysis review process, one of several discussed by Hayes. David Andow gives a thoughtful, if brief, discussion, in the context of pathways, of the differences between ex post and ex ante analyses and what needs to be done. Andow's chapter leads neatly into the third part, a single 46-page chapter by the editors, an attempt at ‘A conceptual framework for management’. Apparently this is a shortened version of a chapter in the much delayed overview volume of GISP I. It has much sensible comment with interesting ideas and I was glad to see my aphorism ‘explanation is not prediction’ which encapsulates a fundamental difficulty with invasion risk analysis. Even so, this chapter is largely aspirational, complete with ‘an ecologist's graph’ (a diagram with speculative lines and no numbers on either axis). But management has to be done now and this chapter is a useful guide about how management of pathways can be improved while we learn more about the science. Altogether, this is a most useful book, but it shows too how much we still have to do.