12.1 Introduction
195
have happened. High populations by AD 1400, the beginning of the Little Ice Age,
in turn imply significant time depth for settlement in New Zealand, given that till
AD 1200 New Zealand would have had a population growth level consistent with a
settled hunter/gatherer population, rather than with a horticulturally based society.
If there were high populations at the beginning of the Medieval Climatic
Optimum, the global warm period which Patrick Grant dates to about AD 1180
in New Zealand, this can only have been the result of natural increase over a long
period of time.
Robert May [4] estimates the annual average population growth rate for preagricultural hunter/gatherers was of the order of 0.001% per annum. For present-day
New Guinea hunter/gatherers, Garry Law quotes 0.03% as a possible population
growth rate [5]. These figures, of course, presuppose a long time scale with balance
achieved between population and available resources so that close to a nil growth
rate is being maintained. In New Zealand initial growth rates, even given a settled
hunter/gatherer existence, would have been higher than this. But neither the fast
initial growth rates possible in tropical Polynesian islands with horticulture nor the
rates possible for an agricultural society such as that of medieval England could
be sustained long term in New Zealand. We considered a high initial growth rate
of 0.5% per annum in the last chapter in order to demonstrate its inadequacy for
generating a sizeable population by the time of Cook. A growth rate of this level is
17 times Law’s estimate for New Guinea.
A rate of increase that could enable British populations during the Medieval
Climatic Optimum to triple in 200 years (0.55% per annum) could not be sustained
for long in prehistoric New Zealand and certainly not during the extreme conditions
of the Little Ice Age. Sutton’s study of nutrition, as we have seen, makes it clear
that Maori would always have relied primarily on hunting and fishing and that this
would have continued even after the introduction of the Polynesian cultivars and
the beginning of organized horticulture in New Zealand after about AD 1200. The
extreme cold of the Little Ice Age would have impacted on the biota at every level
in every part of the country: fish, shellfish, birds, seals, forest foods, kumara and
other crops would all have been reduced. If population levels in New Zealand were
high in AD 1400, there would be population decline, probably long and sustained
in New Zealand, rather than short and sudden and tied to specific crop failures in
particular years, as in England and northern Europe. After AD 1400 it would probably have extended to the best lands as well as to the marginal, and there is little
doubt that, as elsewhere in the world in the Little Ice Age, high populations and
sudden reductions in food would have triggered starvation and conflict over land
and resources. Fear of attack and concern with tribal survival are implicit in the
extraordinary level of pa-building in New Zealand. The limited numbers of radiocarbon dates for pa that have so far been obtained place them centrally in the Little
Ice Age. The obvious implication is that populations were high enough for ceilings
of sustainability to have been breached in Little Ice Age New Zealand and so for
starvation and significant population losses to have occurred in New Zealand as in
Europe.
195
have happened. High populations by AD 1400, the beginning of the Little Ice Age,
in turn imply significant time depth for settlement in New Zealand, given that till
AD 1200 New Zealand would have had a population growth level consistent with a
settled hunter/gatherer population, rather than with a horticulturally based society.
If there were high populations at the beginning of the Medieval Climatic
Optimum, the global warm period which Patrick Grant dates to about AD 1180
in New Zealand, this can only have been the result of natural increase over a long
period of time.
Robert May [4] estimates the annual average population growth rate for preagricultural hunter/gatherers was of the order of 0.001% per annum. For present-day
New Guinea hunter/gatherers, Garry Law quotes 0.03% as a possible population
growth rate [5]. These figures, of course, presuppose a long time scale with balance
achieved between population and available resources so that close to a nil growth
rate is being maintained. In New Zealand initial growth rates, even given a settled
hunter/gatherer existence, would have been higher than this. But neither the fast
initial growth rates possible in tropical Polynesian islands with horticulture nor the
rates possible for an agricultural society such as that of medieval England could
be sustained long term in New Zealand. We considered a high initial growth rate
of 0.5% per annum in the last chapter in order to demonstrate its inadequacy for
generating a sizeable population by the time of Cook. A growth rate of this level is
17 times Law’s estimate for New Guinea.
A rate of increase that could enable British populations during the Medieval
Climatic Optimum to triple in 200 years (0.55% per annum) could not be sustained
for long in prehistoric New Zealand and certainly not during the extreme conditions
of the Little Ice Age. Sutton’s study of nutrition, as we have seen, makes it clear
that Maori would always have relied primarily on hunting and fishing and that this
would have continued even after the introduction of the Polynesian cultivars and
the beginning of organized horticulture in New Zealand after about AD 1200. The
extreme cold of the Little Ice Age would have impacted on the biota at every level
in every part of the country: fish, shellfish, birds, seals, forest foods, kumara and
other crops would all have been reduced. If population levels in New Zealand were
high in AD 1400, there would be population decline, probably long and sustained
in New Zealand, rather than short and sudden and tied to specific crop failures in
particular years, as in England and northern Europe. After AD 1400 it would probably have extended to the best lands as well as to the marginal, and there is little
doubt that, as elsewhere in the world in the Little Ice Age, high populations and
sudden reductions in food would have triggered starvation and conflict over land
and resources. Fear of attack and concern with tribal survival are implicit in the
extraordinary level of pa-building in New Zealand. The limited numbers of radiocarbon dates for pa that have so far been obtained place them centrally in the Little
Ice Age. The obvious implication is that populations were high enough for ceilings
of sustainability to have been breached in Little Ice Age New Zealand and so for
starvation and significant population losses to have occurred in New Zealand as in
Europe.