Whereby we communicate with the spirits of science and attempt to discern the meaning of a few of the latest papers. In this issue: how to predict extinction in only eight generations; why soaring testosterone levels ground CEOs; what's keeping basking sharks from rebounding; and who's speaking for beaches.
- On the road to extinction, dwindling populations pass a tipping point beyond which they may not be able to recover. The ability to anticipate this tipping point and to, theoretically, at least, take measures to avoid extinction remains elusive. Now a new paper in Nature argues the causes of a population’s decline are central to the predictability of its extinction. "Specifically, environmental degradation may cause a tipping point in population dynamics, corresponding to a bifurcation in the underlying population growth equations, beyond which decline to extinction is almost certain." Working with lab populations of water fleas, the authors found four statistical indicators heralding extinction as early as 110 days (~8 generations) before the tipping point was passed. Critical to anticipating correctly: reliable baseline data from before environmental deterioration begins. Good reason to exponentially grow the funding for field work.
- According to a new study in the September issue of Management Science, an Icarus effect, of sorts, is caused by the soaring testosterone levels of CEOs. Those suffering high testosterone levels during merger-and-acquisition negotiations drop more deals and also bulldoze their way into more hostile takeover attempts. "We find a strong association between male CEOs being young and their withdrawal rate of initiated mergers and acquisitions," say the authors, who characterize rejectionist younger executives as victims of their own dominance-seeking behavior. "High testosterone responders tend to reject low offers even though this is against their interest."
- NOAA's Fisheries Service has designated the eastern North Pacific basking shark a "species of concern," since it continues to suffer a dramatic population decline despite decreasing fishing pressures. US and Canadian fishing programs ended in the 1970s, yet the population has not rebounded, probably because of low reproductive rates, vessel strikes, fisheries bycatch, and illegal shark finning. Whereas schools of thousands used to occur off California in the mid 20th century, no more than three individual basking sharks have been observed at any one time since 1993. More or less ditto for Canadian waters. The current eastern North Pacific population size is estimated at 300 to 500 animals. That means the current basking shark population in the northeast Pacific is roughly 10 percent of pre-hunting levels. A fate befalling so many of the big fish. (What would the model from the Nature study, above, show if we plugged the basking shark data into it?)
- Four IPCC reports on global climate change mostly overlooked the impacts of a warming world on marine ecosystems. That prompted a review in Science last June by noted marine researchers. And that led to a letter in the current Science arguing that beaches are getting even less of their due than other marine ecosystems. "Specifically, there are no studies of climate change impacts to sandy beach ecosystems. Rather than any oversight by... previous authors, we believe that the omission of beaches from this and other assessments of anthropogenic impacts reflects a relative lack of appreciation of beaches as ecosystems. This paucity of beach studies is alarming, not only because beaches comprise ~70% of open-ocean coasts and have high socioeconomic and ecosystem value, but also because their position at the land-sea margin renders them highly vulnerable to climate change... The inadequacy of information on ecological impacts of climate change on this vulnerable and challenged coastal ecosystem must be addressed."