The Mathematical Demography of the California Condor Population

The California spotted owl: a technical assessment of its current status

“…In this chapter, we present analyses of available demographic data on the California spotted owl, using life-history and demographic information in an approach similar to that of Mertz (1971), Nichols et al (1980), Noon and Biles (1990), and Thomas et al (1990, appendix L). Our objectives were (1) to characterize the life-history structure of the California spotted owl, (2) to estimate values of the demographic parameters needed to compute rates of population change, (3) to test the sensitivity of the rate of population change to each of the demographic parameters, (4) to infer which parameters may be most influenced by management decisions, and (5) to suggest future research priorities, as indicated by the demographic analyses.…”

Evolution of marine mammal hunting: A view from the California and Oregon coasts

“…The biological community is largely in agreement, however, that pinnipeds are K-strategists (Eber hardt 1977); they have a low rate of population increase, delayed repro duction, small litter size, large body mass, high survival, long life span, and relatively stable populations (Delany 1982:33). It has further been found that low reproductive rates could only have evolved in a stable environment ~cause populations with a low reproductive potential are unable to withstand increased mortality without decline (Mertz 1971). Populations of marine mammals are particularly sensitive to depletion through exploitation and inclined to recover from such depletion very slowly (Estes 1979(Estes : 1010.…”

EVOLUTION OF INSECT LIFE HISTORIES AND HOST PLANT CHEMISTRY: HISPINE BEETLES ON HELICONIA

“…It is not an adaptation to continued population decline (sensu Mertz, 1971) because there is evidence that this species has recently increased greatly in numbers with man's modification of its habitats. The hypothesis that slow growth is the cost of a K selected adaptation, to shunt energies and nutrients from growth into competitive ability, is not attractive because much evidence suggests competition not to be intense for this species.…”

“…There are several hypotheses in the literature that might be invoked to account for this comparatively slow development, some of which can be ruled out on available evidence: First, there is no reason to suspect it as an adaptation for minimizing fitness losses in a prolonged situation of decreasing population size, as Mertz (1971) proposes might operate for organisms like the California Condor that are on the verge of extinction. Mertz's adaptation would have to be evolved as a result of several generations of declining population size.…”