Sidestep: Extermination of the Moa

It can be proven, it seems, that an extremely low-density human population exterminated New Zealand moa

New Zealand moa are the only late Quaternary megafauna whose extinction was clearly caused by humans. New Zealand offers the best opportunity to estimate the number of people involved in a megafaunal extinction event because, uniquely, both the Polynesian settlement of New Zealand and moa extinction are recent enough to be dated with a high degree of precision. In addition, the founding human population can be estimated from genetic evidence. Here we show that the Polynesian population of New Zealand would not have exceeded 2,000 individuals before extinction of moa populations in the habitable areas of the eastern South Island. During a brief <150 years period and at population densities that never exceeded ~0.01 km2, Polynesians exterminated viable populations of moa both by hunting and removal of habitat indiscriminate burning of forests. It shows that high human population densities are not required in models of megafaunal extinction.

A population in excess of 5,000 individuals has been suggested, but accurate estimates of the human population depend on knowledge of the size of the founding population, potential population growth rates and, especially, the duration of the period of human–moa interaction. Uniquely, the Polynesian settlement of New Zealand and moa extinction are recent enough to be precisely dated, and the mass migrant Polynesian population estimated from genetic evidence, so the New Zealand event offers the best opportunity to estimate the number of people present during a megafaunal extinction. Growth rates of population were taken into account and this can be estimated easily with such a plentiful and energy rich resource was available.

To provide a best estimate for the Polynesian population present during the extinction process, the dates of human settlement and of moa extinction, and hence the duration of the interaction, must be known with at least quasi-decadal precision. We therefore generated independent estimates of the onset and cessation of human interaction with moa from archaeological contexts, and of moa extinction from natural sites in the South Island (see map), where the interaction between Polynesians and moa was most intense and where the best archaeological and palaeontological evidence is available. Much of the South Island, one of the largest (~156,000 km2) temperate islands, is mountainous, so a few moa could have persisted for a few decades in remote areas.

There is no archaeological record of Polynesian settlement of New Zealand indisputably older than the Kaharoa eruption of Mount Tarawera (central North Island), which has been assigned a wiggle-match age of 1314±6 years CE. The earliest well-dated occupation, at Wairau Bar in the north-eastern South Island, dates to near the beginning of the 14th century. Evidence of intense human predation on moa there, and at other early archaeological deposits, includes multi-hectare arrays of ‘moa ovens’, but most 14C ages on archaeological sites in New Zealand are on materials with the potential for unknown inbuilt age (for example, charcoal) or subject to marine reservoir effects, which result in large calibrated age ranges.

Estimates for the founding Polynesian population in New Zealand, on the basis of analysis of the mtDNA haplotypes of the present Maori population, range from ~70 women17 to ~170–230 women (~400 individuals). Despite concerns that the power of such analyses may have been reduced by the effects of a sharp decline in the Maori population after European settlement, the estimate of ~400 individuals accords with oral traditions on the number and carrying capacity of voyaging canoes that reached New Zealand. Just over 450 years later, the population had reached at least 100,000. On the basis of Bayesian analyses of large series of calibrated radiocarbon ages on moa from natural sites and moa eggshell from archaeological sites, constrained by the date for the pre-settlement Kaharoa eruption, we show that Polynesians settled in New Zealand in the early 14th century CE, and that moa went extinct in the early- to mid-15th century CE.

At historically reasonable population growth rates, we show that, starting from a genetically estimated founding population of 400 individuals, the Polynesian population of New Zealand during the period of moa exploitation would not have exceeded 2,000, at a density of ~0.01 km−2. A small population of humans with a basic toolkit of stone tools and fire could, therefore, rapidly eliminate a megafauna by hunting and habitat destruction. Large human populations need not, therefore, necessarily be postulated in the models of megafaunal extinction elsewhere.

Results were made up of several factors of calculation Bayesian chronologies for moa extinction and the period of interaction of humans with moa in the South Island of New Zealand. The period of exploitation of moa eggs by Polynesians in the eastern South Island of New Zealand. Human annual population growth rates used in model for whole prehistory. Human population growth at different annual rates during period of moa hunting, (OK, to be fair we don't understand those things either...) and the human population in early New Zealand in relation to timing of key events as below...

Human population densities through New Zealand prehistory are calculated assuming 2.2% annual growth rate from a founding population of 400 individuals until 1400 CE, then annual growth rate of 1.1% after elimination of megafauna.

The early Polynesian settlers of the South Island are treated here as hunter–gatherers despite their long history of a horticulture-based culture, because of abundant evidence for significant exploitation of wild land and sea foods and sparse evidence for early gardening in the north-eastern South Island and none south of Banks Peninsula. Population growth during the first century of occupation would, therefore, have been sustained largely by a reversion to hunter–gatherer economics, as when other cultures have encountered climates inimical to maintenance of their farming, especially in the presence of abundant natural food resources. After having stable—or even slightly increasing—populations for the previous several thousand years, moa became extinct in the South Island, as a result of hunting and habitat destruction, before 1446 CE, 120 years after the start of the archaeological record in New Zealand. Moa populations were low in the mountainous and wet western areas, so for humans to have eliminated their populations there in a few decades would not have been as difficult as might be imagined. For example, Polynesians had reached the remote alpine Takahe Valley (45°17′24′′S, 167°39′42′′E) and butchered an upland moa there by middle of the 14th century (NZA2227). European gold prospectors explored all but the most remote valleys between 1860 and 1880. The extinction across the entire South Island took at the most five moa generations and was substantially complete within four human generations, insufficient time for the birds to develop anti-predation strategies. It was during this period that the drier eastern forests of the South Island were removed by anthropogenic burning and replaced by tussock grasslands, removing the most productive moa habitat, which contained the most diverse and densest moa populations. This is important to know when some publications point ot forest depletion only since Europeans arrived here and while that was for building purposes, the Maori burned forest for the sole purpose of hunting which in the end depleted both with nothing to show for it afterward.

6.7 million hectares of prime forests were burned by Maori after they arrived. Between 1840 and 2000, another 8 million hectares were cleared by Europeans, mostly lowland or easily accessible conifer–broadleaf forest. So, let's ensure we tell the whole story when referring to flora and fauna depletion in this land.

Polynesians and moa co-existed for, at the very most, 150 of the 450 or so years between settlement and the start of continuous European presence, or roughly one-quarter of the total prehistoric period. Most of the growth in their human populations would have taken place during the period when both the people and the environment were adapting to the loss of the megafauna. The Polynesian population of New Zealand reached at the most 2,000 individuals by the time of moa extinction ~120 years after settlement, and it was <1,500 during the period of most intense exploitation and habitat removal. Even allowing for moa being long-lived birds with protracted growth and low reproductive rates and their being naive to human predation, their extinction was caused by a remarkably low number of people.

Oh, and by the way, of the 56 extinct bird species in NZ since man arrived, just 16 became that way after Europeans arrived. That means 40 bird species are made extinct by Maori hands alone.... before Pakeha ever arrived here. You won't find that in the new NZ school curriculum of 2022! These bones are what Makere Chapman calls tūpuna or ancestors, because they lived when his ancestors did. Yes Makere, that is true. But they also died at the hands of your ancestors, culled, hunted, killed, eaten and then the bones discarded in ovens and around butchery sites. Let's be honest, you can now be sad about what your ancestors did and call it for what it was, but don't make it out to be some romantic nonsense about preserving the past. Your ancestors exterminated the past. Sorry, but it has to be said alongside the propaganda being taught right now. But yes, revere them within your guilt and sorrow just as Europeans should of other species gone since 1825. Of all extinctions, Maori account for more than Europeans, they only need one more animal to disappear to be on a level playing field with Maori. But that is not what they teach is it? Europeans are guilty of eliminating many species as well, also deforestation.

Forests were burned to flush out moa. Apparently deforestation is solely due to colonisation according to accepted teaching. Yet in just 500 years prior to European arrival, Maori had reduced the forest cover from 85% down to 56%.....and that is a fact. https://teara.govt.nz/en/human-effects-on-the-environment/page-2

One day, maybe all humans in this country will realize no one race or skin colour is blameless? One day!