14.2 New Zealand Palaeodemography
231
so), a very rapid and sustained population growth is required to meet these estimates.
Even assuming an initial population of 300 in AD 1200, the 155,000 figure for 1801
corresponds to an improbably high average rate of growth of 1.045% p.a., while the
175,000 figure gives 1.065% p.a. As we have stressed, these improbably high population growth rates would have to be sustained, against global trends, during the
Little Ice Age.
Even with a first settlement in AD 750, a group of 300 migrants would still
need growth rates of between 0.596 per annum and 0.608% per annum to reach the
estimated 1801 levels.
What light does the demographic work of Brewis et al. shed on Anderson’s late
settlement claim? The abstract to their paper records the implausibility of an earlier
first settlement date of AD 750–950:
Skeletal and comparative evidence of mortality is combined with fertility estimates for the
precontact Maori population of New Zealand to determine the implied rate of precontact
population growth. This rate is found to be too low to populate New Zealand within the
time constraints of its prehistoric sequence, the probable founding population size, and the
probable population size at contact. Rates of growth necessary to populate New Zealand
within the accepted time span are calculated. The differences between this minimum necessary rate and the skeletally derived rate are too large to result solely from inadequacies in
the primary data.
The authors proposed four alternative explanations:
(i) the skeletal evidence of mortality is highly inaccurate;
(ii) the skeletal evidence of fertility severely underestimates actual levels;
(iii) there was very rapid population growth up to AD 1150 for which no skeletal
evidence is currently available;
(iv) the prehistoric sequence of New Zealand may have been longer than generally
accepted.
After some discussion, Brewis et al. concluded that a combination of the last two
was the most probable.
Brewis et al. found a population decline of 0.414% p.a. in association with a
low infant mortality rate of 0.035. In a sample of 172 individuals, there were 6
infant deaths and 141 individuals reaching age 15. This corresponds to p = 141/172
where p denotes the probability at birth that a woman will live to age 15 or more.
Considering the likelihood that infant deaths were under-represented by 24, Brewis
et al. concluded that infant mortality would have been 15.3%, corresponding to p =
141/196. Examining this scenario, the authors obtained a corresponding population
decline of 1.52% p.a., a rate more than three times the already high rate of 0.414%
obtained from the skeletal analysis. Unaware of the climatic factors causing severe
population losses globally during the Little Ice Age, which may have explained and
validated their results, they rejected their own findings, although they could find no
flaw in their approach or analysis.
Faced with the problem of a decreasing population, Brewis et al. proceeded to
calculate, without reference to the skeletal evidence, the population growth rate
231
so), a very rapid and sustained population growth is required to meet these estimates.
Even assuming an initial population of 300 in AD 1200, the 155,000 figure for 1801
corresponds to an improbably high average rate of growth of 1.045% p.a., while the
175,000 figure gives 1.065% p.a. As we have stressed, these improbably high population growth rates would have to be sustained, against global trends, during the
Little Ice Age.
Even with a first settlement in AD 750, a group of 300 migrants would still
need growth rates of between 0.596 per annum and 0.608% per annum to reach the
estimated 1801 levels.
What light does the demographic work of Brewis et al. shed on Anderson’s late
settlement claim? The abstract to their paper records the implausibility of an earlier
first settlement date of AD 750–950:
Skeletal and comparative evidence of mortality is combined with fertility estimates for the
precontact Maori population of New Zealand to determine the implied rate of precontact
population growth. This rate is found to be too low to populate New Zealand within the
time constraints of its prehistoric sequence, the probable founding population size, and the
probable population size at contact. Rates of growth necessary to populate New Zealand
within the accepted time span are calculated. The differences between this minimum necessary rate and the skeletally derived rate are too large to result solely from inadequacies in
the primary data.
The authors proposed four alternative explanations:
(i) the skeletal evidence of mortality is highly inaccurate;
(ii) the skeletal evidence of fertility severely underestimates actual levels;
(iii) there was very rapid population growth up to AD 1150 for which no skeletal
evidence is currently available;
(iv) the prehistoric sequence of New Zealand may have been longer than generally
accepted.
After some discussion, Brewis et al. concluded that a combination of the last two
was the most probable.
Brewis et al. found a population decline of 0.414% p.a. in association with a
low infant mortality rate of 0.035. In a sample of 172 individuals, there were 6
infant deaths and 141 individuals reaching age 15. This corresponds to p = 141/172
where p denotes the probability at birth that a woman will live to age 15 or more.
Considering the likelihood that infant deaths were under-represented by 24, Brewis
et al. concluded that infant mortality would have been 15.3%, corresponding to p =
141/196. Examining this scenario, the authors obtained a corresponding population
decline of 1.52% p.a., a rate more than three times the already high rate of 0.414%
obtained from the skeletal analysis. Unaware of the climatic factors causing severe
population losses globally during the Little Ice Age, which may have explained and
validated their results, they rejected their own findings, although they could find no
flaw in their approach or analysis.
Faced with the problem of a decreasing population, Brewis et al. proceeded to
calculate, without reference to the skeletal evidence, the population growth rate