Molecular biology and evolution in New Zealand
Arguably New Zealand “punches above its weight” in the field of molecular biology and evolution. New Zealand is a small country, with a population of about 4.9 million, but it has a relatively large population involved in academic research across its eight universities, crown research organisations and other institutes and organisations.
In particular, molecular ecology and evolution has a strong history of research by New Zealanders, at home and abroad. Probably the most notable NZer in this field was Allan Wilson, who made major contributions to our understanding of the time scale of hominid evolution using a molecular clock and also led the seminal research that proposed a Mitochondrial Eve. Allan Wilson pursued this work at the prestigious University of California, Berkeley, in USA. But many other significant contributions to our understanding of evolutionary biology have come from researchers based in New Zealand.
This may be partly attributed to New Zealand’s rather unique biota and natural history. New Zealand was the last major hospitable land mass on Earth to be colonised by humans, with Māori arriving about 1000 years ago, followed by a second wave of colonisation from Europe starting about 200 years ago with whalers and sealers. The founding document that formed the modern country is the Treaty of Waitangi / Te Tiriti o Waitangi signed in 1840 between representatives of the British crown and Māori chiefs representing many of the iwi that already lived in NZ before the British arrived.
Because of the recent history of human colonisation in New Zealand, the impact of human activities on the native biota has been somewhat more clear than in many other countries around the world where humanity has lived for generally much longer periods of time. Prior to human settlement, NZ was thought to be almost entirely covered with forest except for alpine regions. However by the time Europeans arrived, roughly half of the lowlands had already been deforested by fire. Approximately 50 endemic animal species became extinct during that time including birds, a bat, amphibians and reptiles, with megafaunal extinctions of a number of moa species and the Haast’s eagle, which preyed upon them.
Organised European settlment accelerated this transformation of the NZ ecosystem with further rapid deforestation, especially in the North island, and the introduction of mammalian predators (such as mice, rats, possums, weasels and stoats). This led to a dramatic decimation of the population of many smaller endemic bird species, including numerous extinctions, the Huia being one of the best-known examples. Some endemic bird species that remain, do so only tenuously with a few closely managed populations in predator-excluded environments that are made so by expensive predator-proof exclusion fences or by being located on offshore islands where predators have been excluded by poisoning and trapping (e.g. Saddleback/Tieke, Stitchbird/Hihi).
New Zealand’s biogeography is also quite unique. New Zealand encompasses two large main islands and hundreds of smaller islands, with the whole land mass being rather remote. The closest continent is Australia, some 1500 kilometres of rugged southern Pacific ocean separating the two land masses between their closest points (roughly Tasmania to Fiordland). From a biogeography perspective New Zealand does not fit neatly into the island biogeography framework, nor is it quite large enough to be considered its own continent. It is large enough for considerable speciation and diversity to have developed endemically (and it has a very high level of endemism, due to its relative remoteness, and relative large size) but it’s diversity has also been maintained by continuous dispersal from the “source” of Australia, both for plant and animal (mainly bird) species. Explaining New Zealand biogeography is therefore a test case for any unified theory of biological diversity.