title: Variation in mandible shape and body size of house mice Mus musculus across the New Zealand archipelago: A Trans-Tasman comparison using geometric morphometrics

authors: West, Annie Grace

subjects: geometric morphometrics

abstract: Islands create unique environments that provide niche expansion opportunities for invading species not previously available on continental areas. This thesis investigates variation in house mouse mandible shape and body size across the New Zealand archipelago, and aims to identify environmental variables that might influence change between island populations using geometric morphometric techniques.
Mice were introduced to New Zealand in the early 19th century with European explorers and settlers. The Mus phylogroups currently known in New Zealand include Mus musculus domesticus, M. m. musculus, and M. m. castaneus. Each of these subspecies has a distinct distribution throughout the archipelago, with M. m. domesticus dominating the northern New Zealand ‘mainland’.
Past studies have shown habitat composition and co-existence with rats can significantly influence the activity and behaviour of house mice. Additionally, environmental events such as seed masting are known to provide abundant food resources that inflate house mouse density. Consequently, different habitats may promote variation in dietary components. Here I examined variation between house mice inhabiting five different forest environments across the North and South Islands. Significant variation in mandible shape and body size was found between all five forest populations. Annual rainfall was the most significant covariate with mandible shape. General variation in body size somewhat followed rising latitude, supporting the general ecological trend known as Bergmann’s rule. Habitat type, ambient temperature, and presence of rats were also significant predictors of body size under regression.
Ecological complexity and biodiversity are known to vary with island size. Islands with greater landmass are associated with increased habitat and species diversity which support heightened competition and predation. Small mammals colonising diminutive, remote islands often experience ecological release from these interactions, leading to the largest cases of gigantism currently known. This study investigated variation between six populations of house mice on small, often very remote islands in the New Zealand archipelago. Significant variation in body size and mandible shape was found between all six populations, but again, rainfall was the most significant covariate with mandible shape. The general pattern in body size between island populations followed Bergmann’s rule, and is also consistent with previous studies that observe an inverse relationship between island size and body size, peaking at 50° latitudes. Ambient temperature, rainfall, and genetics were also significant predictors of body size.
Significant variation was also found between all New Zealand mouse populations compared with samples from Sydney. Australia. Sydney was an important shipping port during the settlement of New Zealand. Modern Sydney house mice are probably descendants of the original population from which northern New Zealand domesticus mice are derived. Sydney mandibles clustered with extreme examples of variation in New Zealand mouse mandible shapes on separate axes. Collectively, these studies describe significant variation between distinct house mouse populations of the New Zealand archipelago, and lay the foundations for further research in this area.

text: Variation in mandible shape and body size of house mice Mus musculus across the New Zealand archipelago: A Trans-Tasman comparison using geometric morphometrics Islands create unique environments that provide niche expansion opportunities for invading species not previously available on continental areas. This thesis investigates variation in house mouse mandible shape and body size across the New Zealand archipelago, and aims to identify environmental variables that might influence change between island populations using geometric morphometric techniques.
Mice were introduced to New Zealand in the early 19th century with European explorers and settlers. The Mus phylogroups currently known in New Zealand include Mus musculus domesticus, M. m. musculus, and M. m. castaneus. Each of these subspecies has a distinct distribution throughout the archipelago, with M. m. domesticus dominating the northern New Zealand ‘mainland’.
Past studies have shown habitat composition and co-existence with rats can significantly influence the activity and behaviour of house mice. Additionally, environmental events such as seed masting are known to provide abundant food resources that inflate house mouse density. Consequently, different habitats may promote variation in dietary components. Here I examined variation between house mice inhabiting five different forest environments across the North and South Islands. Significant variation in mandible shape and body size was found between all five forest populations. Annual rainfall was the most significant covariate with mandible shape. General variation in body size somewhat followed rising latitude, supporting the general ecological trend known as Bergmann’s rule. Habitat type, ambient temperature, and presence of rats were also significant predictors of body size under regression.
Ecological complexity and biodiversity are known to vary with island size. Islands with greater landmass are associated with increased habitat and species diversity which support heightened competition and predation. Small mammals colonising diminutive, remote islands often experience ecological release from these interactions, leading to the largest cases of gigantism currently known. This study investigated variation between six populations of house mice on small, often very remote islands in the New Zealand archipelago. Significant variation in body size and mandible shape was found between all six populations, but again, rainfall was the most significant covariate with mandible shape. The general pattern in body size between island populations followed Bergmann’s rule, and is also consistent with previous studies that observe an inverse relationship between island size and body size, peaking at 50° latitudes. Ambient temperature, rainfall, and genetics were also significant predictors of body size.
Significant variation was also found between all New Zealand mouse populations compared with samples from Sydney. Australia. Sydney was an important shipping port during the settlement of New Zealand. Modern Sydney house mice are probably descendants of the original population from which northern New Zealand domesticus mice are derived. Sydney mandibles clustered with extreme examples of variation in New Zealand mouse mandible shapes on separate axes. Collectively, these studies describe significant variation between distinct house mouse populations of the New Zealand archipelago, and lay the foundations for further research in this area.

year: 2017

title: Australia's Pacific Seasonal Worker Pilot Scheme (PSWPS): Development impacts in the first two years

authors: Gibson, John

subjects: development impacts

abstract: Australia launched the Pacific Seasonal Worker Pilot Scheme in August 2008. This program was designed to alleviate labor shortages for the Australian horticultural industry by providing opportunities for workers from Kiribati, Papua New Guinea, Tonga, and Vanuatu to undertake seasonal work. This paper presents an analysis of the development impacts of this program in the first two years, and compares them to those from New Zealand’s seasonal worker program in the same countries. The overall development impact of the scheme to date is small, since only 215 individuals participated in the program in the first two years. We examine the selection of these workers, finding they tend to come from poorer areas of Tonga, but within these locations, appear to be of average income levels, and indeed are similar in many respects to the workers going to New Zealand. We estimate the gain per participating household to be approximately A$2,600, which is a 39 percent increase in per-capita annual income in participating Tongan households. The aggregate impact to date is small, but the experience of New Zealand’s program shows that seasonal worker programs can potentially have large aggregate effects. Finally, we provide some evidence on worker’s opinions about the program.

text: Australia's Pacific Seasonal Worker Pilot Scheme (PSWPS): Development impacts in the first two years Australia launched the Pacific Seasonal Worker Pilot Scheme in August 2008. This program was designed to alleviate labor shortages for the Australian horticultural industry by providing opportunities for workers from Kiribati, Papua New Guinea, Tonga, and Vanuatu to undertake seasonal work. This paper presents an analysis of the development impacts of this program in the first two years, and compares them to those from New Zealand’s seasonal worker program in the same countries. The overall development impact of the scheme to date is small, since only 215 individuals participated in the program in the first two years. We examine the selection of these workers, finding they tend to come from poorer areas of Tonga, but within these locations, appear to be of average income levels, and indeed are similar in many respects to the workers going to New Zealand. We estimate the gain per participating household to be approximately A$2,600, which is a 39 percent increase in per-capita annual income in participating Tongan households. The aggregate impact to date is small, but the experience of New Zealand’s program shows that seasonal worker programs can potentially have large aggregate effects. Finally, we provide some evidence on worker’s opinions about the program.

year: 2011-06

title: Effects of industry on Maori cultural values: The case of the Tarawera River

authors: Dodd, Materoa

subjects: New Zealand

abstract: The research is a case study of the relationship between three tribes; Te Arawa, Tuwharetoa ki Kawerau and Ngāti Awa and the Tarawera River during the second half of the 20th century when the river was polluted with effluent from pulp and paper mills. It involves the cultural story of the Tarawera River as told by the iwi (tribes) of the river informed by Maori epistemologies and what has come to be known as a ‗kaupapa Maori research' approach. Reference is made to the history, legends, customs and lifestyle that have arisen from the relationship between iwi and the river. It includes comments on the pollution of the river from members of each iwi. The world views, experiences, and perceptions reported on here have forced a fundamental change on the iwi, a change that has affected their cultural and social relationship to the river. The price of economic development on the river has been cultural and ecological genocide. 
The cultural voice echoes a familiar story in indigenous communities. In the Maori context the research provides opportunities for further inquiry into determining the socio-cultural, economic and political future of the iwi of the river.

text: Effects of industry on Maori cultural values: The case of the Tarawera River The research is a case study of the relationship between three tribes; Te Arawa, Tuwharetoa ki Kawerau and Ngāti Awa and the Tarawera River during the second half of the 20th century when the river was polluted with effluent from pulp and paper mills. It involves the cultural story of the Tarawera River as told by the iwi (tribes) of the river informed by Maori epistemologies and what has come to be known as a ‗kaupapa Maori research' approach. Reference is made to the history, legends, customs and lifestyle that have arisen from the relationship between iwi and the river. It includes comments on the pollution of the river from members of each iwi. The world views, experiences, and perceptions reported on here have forced a fundamental change on the iwi, a change that has affected their cultural and social relationship to the river. The price of economic development on the river has been cultural and ecological genocide. 
The cultural voice echoes a familiar story in indigenous communities. In the Maori context the research provides opportunities for further inquiry into determining the socio-cultural, economic and political future of the iwi of the river.

year: 2010