Customer Reviews

The Unified Neutral Theory of Biodiversity and Biogeography (MPB-32) (Monographs in Population Biology)

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A couple of years ago, Dr. Jim Brown (Univ. New Mexico) wrote an article in the National Center for Ecological Analysis and Synthesis (NCEAS) website indicating that he had not seen any really significant new ideas in ecology during the last few year. Well, we have one.
In the hierarchy of biological systems, ecology deals with the highest and most complex levels. Explanation for patterns of abundance and distribution of organisms have been either too specific that only applies to a few species or even one, or too general that can not be tested (remember the ghost of competition's past).
Ecologists working at the community level have mostly been guided by the general principle that interactions tend to determine the diversity of communities. On the larger scale of biogeography, researchers considered that local diversity tends to be a function of a regional species pool. This debate became very contested in the early 1980's and continued for almost a decade, without any meaningful progress. Nonetheless, significant achivements in both areas of inquiry were made.
Hubbell takes advantage of the increased large-scale reasearch in community ecology (like the Smithsonian-MAB biodiversity network of plots) coupled with the ever more manipulative and reductionist approach to biogeography. Is important to add here Hubbell's own contribution to biodiversity research is substantial. Furthermore, the originality of the work is what sets this monograph appart from the last few in the series. The application of random walk models (i.e., ecological drift) to the organization of communities is not a truly new approach. What make is unique is that then he incorporates immigration and extinction rates across space (classical MacArthur-Wilson), and can then predict a range of abundances and distributions. He supplies ample data from tropical systems that agree with model's predictions. The more interesting aspect is when the data doesn't agree. Here there is plenty of productive work to be performed.
One point that Hubbell makes concerning the "triviality" of the nuetrality assumption. Can there be cases when the differential survival of individuals lead to deviations from the theory's prediction? I think that the assumption of neutrality is not as trivial as Hubbell makes it.
Overall, is probably one of the most intriguing and original works of the last decade. If you are interested in ecology, biogeography, and even conservation, this book will challenge what you know and how should we look at patterns and process of biodiversity.

Hubbell's work is interesting and thought-provoking. Unfortunately, his writing ability leaves a lot to be desired. As an applied mathematician working with biologists personally I think you should:
1. Specify your (mathematical) model *without* examples or justifications first.
Hubbell mixes his models with examples and rambling justifications. Poorly constructed ones if you ask me. This makes it hard to pull out what exactly the model is sometimes.
2. Make derivations clear and concise and if complicated put them in appendices. Hubbell does none of these. His mathematical reasoning and writing is far below the standard in science and although impressive for an ecologist, substandard for anyone else. He would have strongly benefitted from having a trained mathematician co-write or at least edit his mathy sections. Many of the results are either well known or would be explained differently by someone trained in the explication of mathematics. The importance of this is huge since the result is sometimes his statements are totally unclear. For example, on page 124 he says "as the sample size increase towards infinity..." This is a sample from a finite sized population. So he should be clear and say either sample with replacement, or also taking the population size to infinity, (which is it!) otherwise it doesn't make sense.

I also find his egoism (common in my experience with ecologists) disappointing. While he may have come up with a new theory of biodiversity, he did not come up with many of the underlying models. Unfortunately, he barely pays any respect to the countless other people who paved the way for his results. For example, his species abundance distribution is just the Ewen's sampling formula from population genetics, derived in 1972. In fact, the model side of the entire theory comes straight out of population genetics. Yes it explains something different, but it would be nice to see something at least some acknowledgement of that (something he is clearly aware of since he cites many of the popgen papers).

Also, the reference list is incomplete and the index is one of the worst I have come across recently. Paying for a good indexer is always worth the money.

In short, the ideas in this book are important, but the book itself is cluttered and not as clear as it could be. So I average 5 stars and 1 star and get 3 stars.

The author presents a thorough case for his neutral theory of biogeography. He gives a full historical account of its development, and presents plenty of results from publications and simulations, essentially expounding point for point the search for more precise answers to the questions, why are there so many species, and why are they distributed they way they are? Full of interesting insights, and many points are applicable to other sciences as well - economics come to mind. One thing that might have been useful is a more explicit discussion of other neutral theories, say the theories of genetic drift, which predate Hubbell's equal named "ecological drift". But within its stated scope the book is very complete and highly readable as well. Maybe I should mention that I am writing as a scientist - it is not a typical pop science book to read on the train. It truly is a science book. It does not demand much prior knowledge but it does demand attention.