Thanks Joe for summarizing and for the link to the book. As always with anything in the popular sphere I’ll reserve judgement until I see the actual research paper (methodology and raw data). In far too many cases, authors extrapolate to make their case rather than arrive at conclusions based on statistically viable results derived from properly designed studies. Until one reads the actual research paper there is simply no way to tell. If correct, the results reported would represent an example of ecosystem exploitation (e.g. members of a species within the same ecosystem will, if biologically possible, vary their patterns of exploitation so as not to overwhelm any single resource) but given the generally poor quality of social-science research it’s probably best (a) to look at the original study, rather than anyone’s summary of it, and (b) wait until these results have been independently verified by at least one other study showing, to P>95, the same phenomenon.