title: Interactions between ship rats and house mice

authors: Bridgman, Lucy Jade

subjects: Rattus rattus

abstract: Interactions between coexisting invasive species can cause complications when their populations are managed to protect native biodiversity. The ship rat (Rattus rattus) is a widespread invasive species often targeted for management because of its negative impacts on native wildlife, particularly in otherwise mammal-depauperate ecosystems such as in New Zealand. However, where ship rats are removed, another common, coexisting invasive species, the house mouse (Mus musculus), is often detected more frequently, which may undermine the benefit of the management operation for biodiversity. The aim of this study was to better understand why house mice become more abundant, or potentially also more active and detectable, when released from suppression by ship rats through determining the mechanism involved. The hypothesised mechanisms were: exploitation competition, interference competition and intraguild predation. 

Focusing on New Zealand, I reviewed diet studies of ship rats and house mice to have a clearer understanding of the resources they may share. I found that whilst some features of their diets differ, ship rats and house mice do show overlap in the range of food items they consume. Therefore they could compete for these shared resources if they were limited. However, in captive experiments I confirmed that ship rats exhibit predatory aggression towards house mice and therefore have potential to directly negatively influence mouse populations regardless of resource availability. 

In response to the threat of predation by ship rats, house mice exhibited avoidance of caged rats during further captive experiments and this restricted their foraging choices. In the field, the foraging behaviour of mice in podocarp-broadleaf forest was also limited by the risk posed from abundant ship rats, which prevented them from accessing resources. In similar habitat at Pureora Forest Park during a longer term study of mouse populations, mice captured when ship rats were abundant had lower body mass compared to those captured when ship rats were controlled, an effect that was not offset by supplementary feeding.

At Pureora, the ship rat control operations did not achieve optimal low ship rat levels, however, despite small mouse sample sizes, both the abundance of mice measured by live-trapping and their activity in tracking tunnels were positively affected. These measures were moderately correlated indicating that activity was related to mouse abundance. However, capture probability varied seasonally and according to rat abundance in unexpected ways, indicating more subtle and complex potential influences of ship rats on the probability of detecting mice. 

My results indicate that the main mechanism by which ship rats suppress house mice is intraguild predation. This is because though apparently food restricted, house mice did not access resources I provided for them when ship rats were abundant, which rules out exploitation competition. Ship rats appear to view house mice as prey and opportunistically consume them, which differentiates intraguild predation from interference competition as the latter is primarily driven by resource defence. Even if predation events are rare, my research demonstrates that the risk effects of avoiding an abundant opportunistic predator appear to have a strong influence on the abundance and distribution of house mice.

text: Interactions between ship rats and house mice Interactions between coexisting invasive species can cause complications when their populations are managed to protect native biodiversity. The ship rat (Rattus rattus) is a widespread invasive species often targeted for management because of its negative impacts on native wildlife, particularly in otherwise mammal-depauperate ecosystems such as in New Zealand. However, where ship rats are removed, another common, coexisting invasive species, the house mouse (Mus musculus), is often detected more frequently, which may undermine the benefit of the management operation for biodiversity. The aim of this study was to better understand why house mice become more abundant, or potentially also more active and detectable, when released from suppression by ship rats through determining the mechanism involved. The hypothesised mechanisms were: exploitation competition, interference competition and intraguild predation. 

Focusing on New Zealand, I reviewed diet studies of ship rats and house mice to have a clearer understanding of the resources they may share. I found that whilst some features of their diets differ, ship rats and house mice do show overlap in the range of food items they consume. Therefore they could compete for these shared resources if they were limited. However, in captive experiments I confirmed that ship rats exhibit predatory aggression towards house mice and therefore have potential to directly negatively influence mouse populations regardless of resource availability. 

In response to the threat of predation by ship rats, house mice exhibited avoidance of caged rats during further captive experiments and this restricted their foraging choices. In the field, the foraging behaviour of mice in podocarp-broadleaf forest was also limited by the risk posed from abundant ship rats, which prevented them from accessing resources. In similar habitat at Pureora Forest Park during a longer term study of mouse populations, mice captured when ship rats were abundant had lower body mass compared to those captured when ship rats were controlled, an effect that was not offset by supplementary feeding.

At Pureora, the ship rat control operations did not achieve optimal low ship rat levels, however, despite small mouse sample sizes, both the abundance of mice measured by live-trapping and their activity in tracking tunnels were positively affected. These measures were moderately correlated indicating that activity was related to mouse abundance. However, capture probability varied seasonally and according to rat abundance in unexpected ways, indicating more subtle and complex potential influences of ship rats on the probability of detecting mice. 

My results indicate that the main mechanism by which ship rats suppress house mice is intraguild predation. This is because though apparently food restricted, house mice did not access resources I provided for them when ship rats were abundant, which rules out exploitation competition. Ship rats appear to view house mice as prey and opportunistically consume them, which differentiates intraguild predation from interference competition as the latter is primarily driven by resource defence. Even if predation events are rare, my research demonstrates that the risk effects of avoiding an abundant opportunistic predator appear to have a strong influence on the abundance and distribution of house mice.

year: 2012

title: Music information retrieval research and its context at the University of Waikato

authors: Bainbridge, David

subjects: computer science

abstract: This article describes the digital music library work at the University of Waikato, New Zealand. At the heart of the project is a music information retrieval workbench for evaluating algorithms and performing experiments used in conjunction with four datasets of symbolic notation ranging from contemporary to classical pieces. The outcome of this experimentation is woven together with strands from our larger digital library project to form the Web-based music digital library MELDEX (short for melody index). An overview of the workbench software architecture is given along with a description of how this fits the larger digital library design, followed by several examples of MELDEX in use.

text: Music information retrieval research and its context at the University of Waikato This article describes the digital music library work at the University of Waikato, New Zealand. At the heart of the project is a music information retrieval workbench for evaluating algorithms and performing experiments used in conjunction with four datasets of symbolic notation ranging from contemporary to classical pieces. The outcome of this experimentation is woven together with strands from our larger digital library project to form the Web-based music digital library MELDEX (short for melody index). An overview of the workbench software architecture is given along with a description of how this fits the larger digital library design, followed by several examples of MELDEX in use.

year: 2004

title: Defence not defiance: The shaping of New Zealand’s volunteer force

authors: Clayton, Garry James

subjects: New Zealand Army history

abstract: In the latter half of the nineteenth century and the first decade of the twentieth New Zealand's land defences were primarily the responsibility of its Volunteer Force. This Force over a period of fifty-two years evolved from ill-considered vigilante bands to a well organised and disciplined Army. This thesis examines the evolution of this Volunteer Army in chronological sequence concentrating on the factors which shaped and developed it.
The preface provides a brief outline of this study on New Zealand's Volunteer Force. The thesis then presents the history of the Force in eight chapters. These chapters are in four basic divisions. The first section, of three chapters. examines the origins of the Force, its role in the New Zealand Wars and its subsequent development in the period of tenuous peace during the 1870's . The second section, comprising of two chapters only, examines the transformation of the Volunteers from a military body which primarily looked inward. into a Force which concentrated on protecting the nation's main ports. The third section , also comprising two chapters , then views the development of this coastal protection Force into a Colonial Army, able and willing to provide for the nation's own security as well as expeditionary units to· serve with the British Imperial Forces ·. The last Section, of one Chapter only, concentrates on the demise of Volunteering and the moves to compulsory military training. The conclusion then draws together the analytical threads of the thesis. 
As the thesis is extensive in its coverage of time, it is only possible to outline the very nature of Volunteering. It will be for Regimental Historians to show the uniqueness of each of the 658 different units that comprised the New Zealand Volunteer Force over its fifty-two years of existence. What this broad survey does do, however, is provide a unique window for the examination of the development of an embryonic Colonial Army in the context of a developing nation.

text: Defence not defiance: The shaping of New Zealand’s volunteer force In the latter half of the nineteenth century and the first decade of the twentieth New Zealand's land defences were primarily the responsibility of its Volunteer Force. This Force over a period of fifty-two years evolved from ill-considered vigilante bands to a well organised and disciplined Army. This thesis examines the evolution of this Volunteer Army in chronological sequence concentrating on the factors which shaped and developed it.
The preface provides a brief outline of this study on New Zealand's Volunteer Force. The thesis then presents the history of the Force in eight chapters. These chapters are in four basic divisions. The first section, of three chapters. examines the origins of the Force, its role in the New Zealand Wars and its subsequent development in the period of tenuous peace during the 1870's . The second section, comprising of two chapters only, examines the transformation of the Volunteers from a military body which primarily looked inward. into a Force which concentrated on protecting the nation's main ports. The third section , also comprising two chapters , then views the development of this coastal protection Force into a Colonial Army, able and willing to provide for the nation's own security as well as expeditionary units to· serve with the British Imperial Forces ·. The last Section, of one Chapter only, concentrates on the demise of Volunteering and the moves to compulsory military training. The conclusion then draws together the analytical threads of the thesis. 
As the thesis is extensive in its coverage of time, it is only possible to outline the very nature of Volunteering. It will be for Regimental Historians to show the uniqueness of each of the 658 different units that comprised the New Zealand Volunteer Force over its fifty-two years of existence. What this broad survey does do, however, is provide a unique window for the examination of the development of an embryonic Colonial Army in the context of a developing nation.

year: 1990