Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Stability and instability in ungulate populations
T2 - An empirical analysis
AU - Clutton-Brock, T. H.
AU - Illus, A. W.
AU - Wilson, K.
AU - Grenfell, B. T.
AU - MacColl, A. D.C.
AU - Albon, S. D.
PY - 1997/4/25
Y1 - 1997/4/25
N2 - While many populations of large mammals are stable from year to year, some show persistent oscillations associated with high mortality. This article investigates the causes of variation in population stability in ungulates by comparing the contrasting dynamics of two naturally regulated island populations: the Soay sheep population of Hirta (St. Kilda), where numbers fluctuate by 60%-70% every 3 or 4 yr as a result of overcompensatory winter mortality, and the red deer population of the North Block of Rum, where numbers have been stable for over a decade. We suggest that the contrasting dynamics of these two populations are caused by differences in fecundity and maturation rate. Red deer show relatively low fecundity and slow maturation, and increases in population density depress both fecundity and juvenile survival. In contrast, the relatively rapid development of Soay sheep allows them to evade density-dependent effects on reproduction and survival until the population exceeds winter carrying capacity by a substantial margin, subsequently triggering overcompensatory mortality in late winter in all age classes.
AB - While many populations of large mammals are stable from year to year, some show persistent oscillations associated with high mortality. This article investigates the causes of variation in population stability in ungulates by comparing the contrasting dynamics of two naturally regulated island populations: the Soay sheep population of Hirta (St. Kilda), where numbers fluctuate by 60%-70% every 3 or 4 yr as a result of overcompensatory winter mortality, and the red deer population of the North Block of Rum, where numbers have been stable for over a decade. We suggest that the contrasting dynamics of these two populations are caused by differences in fecundity and maturation rate. Red deer show relatively low fecundity and slow maturation, and increases in population density depress both fecundity and juvenile survival. In contrast, the relatively rapid development of Soay sheep allows them to evade density-dependent effects on reproduction and survival until the population exceeds winter carrying capacity by a substantial margin, subsequently triggering overcompensatory mortality in late winter in all age classes.
U2 - 10.1086/285987
DO - 10.1086/285987
M3 - Journal article
AN - SCOPUS:0030618143
VL - 149
SP - 195
EP - 219
JO - American Naturalist
JF - American Naturalist
SN - 0003-0147
IS - 2
ER -