Environmental Engineering Reference
In-Depth Information
4
Ecological Limits and the
Size of Populations
T
HE ECOLOGIST AND CONSERVATIONIST
G
RAEME
C
AUGHLEY
(1976
B
)
WROTE
that all problems in wildlife management and conservation fall into one of
three categories: (1) too many (overabundance), (2) too few (threatened and
endangered), and (3) too many harvested. But, this begs the question:Too
many or too few relative to what reference? In many cases, such as for ex-
ample the problem of overabundance of North American white-tailed deer
(
Odocoileus virginanus
; McShea et al. 1997; Cote et al. 2004), the frame of ref-
erence often involves the biological properties of the population intertwined
with human perception (Sinclair 1997). As a consequence, scientific prin-
ciples sometimes are muddled by differing human values, which, in turn,
can cloud the policy debate about what management actions to take.
For example, to those who wish to avoid car accidents or the destruc-
tion of ornamental garden plants, even one deer may be too many.Those
who oppose killing deer to reduce their population size, counterargue that
the presence of one or a few individual deer within a local area is insuffi-
cient evidence to claim an overabundance problem. Either way, such val-
ues may or may not have any relation to the number of deer the natural
environment can support. In order to have productive policy debates, we
need to disentangle biological principles from value judgments.This requires
first understanding basic principles of population dynamics and factors that
may limit population size followed by application of these principles to rec-
oncile human values of abundance with the biological capacity of the en-
vironment to support a population.
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