New Zealand History II – Impacts of Settlement

Overview of Aotearoa/New Zealand Colonization

• The history of Aotearoa/New Zealand is defined by two primary periods of colonization: the arrival of Māori and the later arrival of Europeans.

• Both periods resulted in extensive habitat loss and successive waves of species extinction.

• Māori Period: Characterized by the eradication of large-bodied animals and flightless birds through hunting and habitat modification.

• European Period: Characterized by the introduction of predatory mammals that targeted the remaining native species, alongside massive land clearance for agriculture.

Pre-human Aotearoa (~$1000\,\text{AD}$)

• Vegetation Cover: Approximately $85-90\%$ of the country was heavily forested.

  • Low scrub and herbaceous communities were restricted to areas above the treeline and dry inland regions of the South Island.

  • The South Island was dominated by beech forests ($Nothofagus$).

  • The North Island was dominated by podocarp-broadleaf forests.

• Native Fauna Biodiversity:

  • Freshwater Life: Included various fish species, kōura (freshwater crayfish), and shellfish such as freshwater mussels.

  • Marine Life: Diverse fishes, shellfish, and marine mammals including whales, dolphins, sea lions, and fur seals.

  • Land Mammals: Limited solely to bats, with $3$ distinct species.

  • Reptiles: Included the Tuatara and over $100$ species of skinks and geckos.

Avian Diversity in Pre-human Aotearoa

• Breeding Bird Species by Region (at first human contact):

  • Norfolk Island: $34$ species

  • Kermadec Islands: $21$ species

  • Northern offshore islands: $62$ species

  • North Island: $100$ species

  • South Island: $113$ species

  • Southern offshore islands: $60$ species

  • Stewart Island: $65$ species

  • Chatham Islands: $60$ species

  • Subantarctic Islands: $68$ species

  • Total: $245$ breeding species across the New Zealand region.

• Endemic Orders and Families:

  • Apterygiformes: Kiwi ($5$ species).

  • Dinornithiformes: Moa ($9$ species).

• Distinctive Physical Features:

  • Gigantism: Examples include the New Zealand eagle ($Aquila\,moorei$), weighing up to $15\,kg$, as well as New Zealand geese and the Adzebill.

  • Flightlessness: A significant portion of the fauna was flightless, including $5$ species of Kiwi, $9$ species of Moa, $2$ species of geese, $7$ species of penguins, the Takahe ($2$ species), the Kakapo, the Adzebill, and various wrens and rails.

• Ecological Naivety: Native species evolved without human or mammalian predators, making them uniquely vulnerable upon human arrival.

The Arrival and Occupation of Māori

• Timing and Evidence:

  • Humans arrived from central eastern Polynesia as part of a southern voyage.

  • Evidence from dating charcoal (forest burning) and rat-gnawed seeds converges on a colonization date of approximately $1280\,\text{AD}$.

• Māori Historical Periods:

  • Archaic Period ($1300-1500\,\text{AD}$): Cultural development was centered in the Otago region. Settlements were usually within $10\,km$ of the coast, ranging from $40$ to $300-400\,\text{people}$. This period is noted for a lack of weapons and fortifications.

  • Classic Period ($1500-1642\,\text{AD}$): Marked by a colder climate and natural disasters (earthquakes in the Southern Alps and Wellington, tsunamis). This led to resource loss and the development of fortified pā and a more defensive culture.

Ecological Impacts of Māori Settlement

• Deforestation: Māori used fire as a deliberate tool to open the countryside and convert forest into fern habitats to harvest edible tubers.

• Land Transformation:

  • Low and middle-elevation dry sites saw permanent conversion from closed forest to tussock grasslands and fern-shrubland.

  • Approximately $6.7 \times 10^6\,ha$ of forest were lost during this period.

  • Fire activity caused slope instability, erosion, and changes in lake chemistry due to sediment import.

• Impact on Wildlife:

  • Hunting and predation by kiore (Pacific rat) decimated populations of terrestrial birds, marine bird/mammal colonies, reptiles, and large insects.

  • The Moa Extinction: There were an estimated > 1.0 \times 10^6 moa when humans arrived. Hunting lasted only $150\,years$, and the moa were extinct within $200\,years$. The loss of the moa resulted in the extinction of its primary predator, the Haast's eagle ($Aquila\,moorei$).

  • Species Turnover: Genetic documentation shows the extinction of the Waitaha penguin (replaced by the yellow-eyed penguin/Hoiho) and changes in sea lion populations.

• Introduced Species:

  • Kiore (Pacific Rat): Valued as food but responsible for the extinction of small birds and frogs.

  • Kurī (Polynesian Dog): Likely contributed to the decline of ground-dwelling species.

Māori Subsistence and Diet

• Dietary Shift: Settlers transitioned from a carbohydrate-rich Pacific diet (kūmara, taro, yams, breadfruit, bananas) to a protein-rich diet in Aotearoa.

• Plant Resources:

  • Kūmara was grown in warmer areas.

  • Fern root (aruhe) was dug up, dried, roasted, and ground.

  • Young cabbage trees (tī kōuka) and tree ferns provided edible stems and tap-roots, cooked in an umu.

• Midden Evidence: Archaeological middens reveal the remains of a vast array of consumed species, including fur seals, sea lions, whales (Fin whale, Orca), fish (Snapper, Barracouta, Red cod), and numerous birds (Tui, Kakapo, Moa).

European Arrival and Direct Impacts

• Contact Timeline:

  • Abel Tasman ($1642\,\text{AD}$): Did not land.

  • James Cook ($1769\,\text{AD}$).

  • Extensive settlement began in the $1800s$.

• Deforestation and Land Clearing: Between $1840$ and $2000$, an additional $8.0 \times 10^6\,ha$ of forest were cleared, primarily lowland conifer-broadleaf forests, to establish farms.

• Wetland Loss: Farming led to the drainage of $90\%$ of New Zealand's original wetlands.

• Hunting and Collection: In the $1800s$, there was a major export of bird specimens to Europe. By $1880$, the market was so saturated that one London dealer had over $385$ Kakapo ($Strigops\,habroptilus$) and $90$ Little spotted kiwi ($Apteryx\,owenii$) skins they could not sell.

Indirect European Impacts: Introduced Predators

• Chronic Predation: The introduction of mammalian predators had the most devastating impact on native fauna.

• Chronology of Introductions:

  • Norway Rat: c. $1770$

  • Pigs: $1790$

  • Feral Cat: $1820$ onwards

  • Mice: $1824$

  • Brushtail Possums: $1858$

  • Black (Ship) Rat: $1860$ onwards

  • Hedgehogs: $1870$

  • Ferret: $1879$

  • Stoat: $1884$

  • Weasel: $1884$

• Impact Study (Braided Rivers): Research on South Island riverbeds shows high predation rates on shorebird nests, with hedgehogs accounting for up to $51\%$ of nest predation at specific sites (e.g., Lower Tekapō).

Extinctions During the European Period

• Recent Extinctions: $16$ bird species were lost, almost entirely due to predation, including:

  • Huia ($Heteralocha\,acutirostris$)

  • Laughing owl ($Sceloglaux\,albifacies$)

  • Bush wren ($Xenicus\,longipes$)

  • Lyall's wren ($Traversia\,lyalli$)

  • New Zealand quail ($Coturnix\,novaezelandiae$)

  • Piopio (North and South Island species)

• Big South Cape Island Incident ($1964$): An invasion of Ship Rats eradicated the last known populations of the Greater Short-tailed Bat, Stead’s Bush Wren, and South Island Snipe. The South Island Saddleback was saved through emergency translocation.

• Non-Avian Extinctions:

  • Fish: New Zealand grayling ($1930$).

  • Molluscs: $6$ species of terrestrial molluscs.

  • Insects: $1$ species ($Mecodema$ ground beetle, $1931$).

Commercial Exploitation of Marine Mammals

• Whaling and Sealing: During the first $40\,years$ of the $19th\,century$, whaling was the most significant economic activity for Europeans.

• Sperm and Right Whales: Initially hunted from visiting ships, then by shore-based stations.

• Humpback Whales: Perano's station in Tory Channel (Cook Strait) caught $4200$ whales between $1911$ and $1964$.

Summary of Impacts

• Māori Wave: Impacted large-bodied megafauna and ground-dwelling birds primarily through hunting, kiore predation, and wide-scale fire usage.

• European Wave: Impacted a broader range of species through massive habitat destruction (lowland forests and wetlands) and a secondary, more lethal wave of mammalian predators (mustelids, cats, and ship rats).

Questions & Discussion

• How do we know when humans arrived? Through carbon dating of charcoal from forest fires and specific evidence like rat-gnawed seeds that align to approximately $1280\,\text{AD}$.

• How long did moa survive human contact? They were hunted to extinction within roughly $200\,years$.

• Comparison of extinction characteristics: Māori-period extinctions were largely large-bodied or flightless "food" species. European-period extinctions were driven by predation on smaller, remaining species.

• Extent of forest loss: Māori cleared $6.7 \times 10^6\,ha$, while Europeans cleared another $8.0 \times 10^6\,ha$.

• The role of mustelids: While mustelids are lethal predators today, they are linked to fewer total extinctions than rats or cats because many vulnerable species had already been wiped out or restricted to offshore islands before mustelids were introduced in the late $1800s$.