Jn. Mcnair, ONTOGENIC PATTERNS OF DENSITY-DEPENDENT MORTALITY - CONTRASTING STABILITY EFFECTS IN POPULATIONS WITH ADULT DOMINANCE, Journal of theoretical biology, 175(2), 1995, pp. 207-230
Several stage-structured population models are considered in which fec
undity, mortality, and maturation to the next stage are allowed to dep
end on stage and within-stage age, and in which adults are assumed to
be the dominant consumers of limiting resources. Local stability effec
ts of changing the strength of regulation about a fixed equilibrium po
int are examined. The main result is that shifting the principal targe
t of strongly density-dependent mortality from adults to progressively
earlier phases of juvenile development reverses the stability effect
of such mortality from locally stabilizing to destabilizing. This resu
lt holds for all the models studied and therefore appears to be fairly
robust to the pattern of age-dependence in adult fecundity and the sh
ape of the juvenile period's durational distribution. A simple intuiti
ve interpretation is developed which can account for these and several
related results in the literature. The necessity of distinguishing be
tween life-historical delays and regulatory delays is also discussed.
(C) 1995 Academic Press Limited