CHINESE WILDLIFE SCIENCE - Wildlife Conservation in China: Preserving the Habitat of China's Wild West - page 195

hand, and uncooperative wild animals living in vast places that are expensive and dif-
ficult to move around in on the other, it is no wonder that Chinese wildlife scientists are
frustrated. Provided with scant financial and logistical resources to begin with, they are
expected to produce precision on a subject that defies all attempts to do so.
A potentially more troubling example of unwillingness to countenance uncertainty
comes from the attempt to estimate sustainable yield for a given animal population. The
practice of harvesting wildlife with governmental monitoring and regulation is so com-
mon in rural and lightly populated areas of North America, Europe, and elsewhere that
it may come as a surprise to the nonspecialist that scientific determinations of maximum
sustainable yield for populations of animals subject to recreational hunting are almost never
conducted. Although the theory of how this might be accomplished is well established,
doing so in practice would require not only timely, accurate, and precise estimation of
the abundance of the animals in question, but also a thorough understanding of exactly
how the population will respond to the removal of a given number of animals of specified
ages and sexes and under a variety of environmental conditions (including the presence
of competitor and predatory species) that might also influence future population growth.
Such detailed knowledge almost always requires years of intensive study, and thus has
been accomplished only in limited, research settings.
In a monograph providing biological background for a proposed new nature reserve in
Gansu, one suggestion put forth for generating needed revenue was to initiate or expand
trophy hunting of high-priced ungulates (a suggestion that, by now, should come as no
surprise). 7 But unlike what actually occurs in management of the existing hunting areas
(Chapter 8), the monograph—being an ostensibly scientific work, and thus having to
distinguish itself from the more ad hoc methods adopted by Chinese agencies actually
responsible for the hunts—included an estimate not only of the population size for fo-
cal species (which were, unsurprisingly, argali, and—somewhat more oddly—goitered
gazelle) but of the maximum sustainable yield (and, by extension, revenue) that could
be expected. In the case of argali, the author estimated a yearly sustainable yield of 247
trophies, a figure that, I suspect, is too high by a factor of about fifty. How did they use
“science” to develop such an astounding estimate?
First, the authors estimated the number of argali within the area to be 3,294 (failing,
notably, to accompany this estimate by confidence intervals, which were almost cer-
tainly very broad). This estimate in turn was based on observation of a grand total of six
argali groups, and was almost certainly based on a highly biased sampling procedure.
Second, the authors employed a well-known but biologically unrealistic model known as
the logistic growth model 8 to calculate the population's maximum offtake rate from its
maximum possible growth rate. Third, the logistic model requires input of a maximum
possible growth rate, and despite its centrality, the value the author used was a complete
guess, interpolated from other species under a wide variety of conditions. 9 The model
also required quantification of the argali population's carrying capacity (i.e., the density at
which losses would, over time, cancel out gains), which the author similarly had no way to
determine. Instead, he assumed that the carrying capacity was identical to the guessed-at
population size, thus substituting one dubiously obtained parameter for another. Finally,