title: Land use, associated eel production, and abundance of fish and crayfish in streams in Waikato, New Zealand

authors: Hicks, Brendan J.

subjects: biology

abstract: The density and biomass of fish and crayfish, and the production of eels, was compared among streams in native forest, exotic forest, and pasture. Populations were estimated by multiple-pass electroshocking at 11 sites in hill-country streams in the Waikato region, North Island. Three sites were in native forest, four in exotic forest, and four in pasture. Length of stream sampled at each site was 46-94 m (41-246 m2 in area), and catchment areas up stream of the sites ranged from 0.44 to 2.01 km2. 
A total of 487 fish were caught. The species were longfinned and shortfinned eels, banded kokopu, Cran's and redfinned bullies, and common smelt. Eels were the most abundant fish in all three land-use types, and shortfinned eels were more abundant at pastoral sites (mean density 1.11 fish m-2) than longfinned eels (mean density 0.129 fish m-2). Banded kokopu were present only at forested sites. Mean fish densities were greater at pastoral sites (1.55 fish m-2) than under either native forest (0.130 fish m-2) or exotic forest (0.229 fish m-2). Mean fish biomass was also greater at pastoral sites (89.7 g m-2) than under native forest (12.8 g m-2) or exotic forest (19.3 g m-2). Longfinned eels made a greater contribution to the fish biomass at all sites than did shortfinned eels. Densities of crayfish were high (0.46-5.40 crayfish m-2), but were not significantly different between land-use types. Crayfish biomass ranged from 1.79 to 11.2 g m-2. Total eel production was greater at pastoral sites (mean 17.9 g m-2 year-1) than at forest sites (mean 2.39 g m-2 year-1).

text: Land use, associated eel production, and abundance of fish and crayfish in streams in Waikato, New Zealand The density and biomass of fish and crayfish, and the production of eels, was compared among streams in native forest, exotic forest, and pasture. Populations were estimated by multiple-pass electroshocking at 11 sites in hill-country streams in the Waikato region, North Island. Three sites were in native forest, four in exotic forest, and four in pasture. Length of stream sampled at each site was 46-94 m (41-246 m2 in area), and catchment areas up stream of the sites ranged from 0.44 to 2.01 km2. 
A total of 487 fish were caught. The species were longfinned and shortfinned eels, banded kokopu, Cran's and redfinned bullies, and common smelt. Eels were the most abundant fish in all three land-use types, and shortfinned eels were more abundant at pastoral sites (mean density 1.11 fish m-2) than longfinned eels (mean density 0.129 fish m-2). Banded kokopu were present only at forested sites. Mean fish densities were greater at pastoral sites (1.55 fish m-2) than under either native forest (0.130 fish m-2) or exotic forest (0.229 fish m-2). Mean fish biomass was also greater at pastoral sites (89.7 g m-2) than under native forest (12.8 g m-2) or exotic forest (19.3 g m-2). Longfinned eels made a greater contribution to the fish biomass at all sites than did shortfinned eels. Densities of crayfish were high (0.46-5.40 crayfish m-2), but were not significantly different between land-use types. Crayfish biomass ranged from 1.79 to 11.2 g m-2. Total eel production was greater at pastoral sites (mean 17.9 g m-2 year-1) than at forest sites (mean 2.39 g m-2 year-1).

year: 1997

title: Distributed Operating Systems on Wireless Sensor Networks

authors: Hunkin, Paul Wade

subjects: Wireless Sensor Networks

abstract: This thesis proposes the use of traditional distributed operating system and distributed systems techniques that are adapted and applied to the wireless sensor network domain. These techniques are applied to the creation of a wireless sensor network operating system that allows complex applications to be created without special programmer knowledge of sensor network programming or architecture. The resulting system is capable of executing a high level user application written in conventional single-system-image form, without the user being aware of the mesh architecture or underlying sensor node hardware.

A wireless sensor network is a collection of battery-powered embedded systems that communicate over low-bandwidth radio. Because of their limited hardware, niche deployments and use of embedded processors, programming techniques for wireless sensor network nodes are generally relatively esoteric compared to most software programming tasks. This can be relatively complex for programmers not familiar with the wireless sensor network domain. A naive approach to writing a wireless sensor network application may well result in considerably reduced battery life due to inefficient use of the limited power resources, requiring an expensive and time-consuming replacement or patching process. 

As a result of this complexity, traditional wireless sensor network applications are written as simply as possible. The majority of these applications simply move passive data readings back across a mesh to a more powerful server. While this is a sufficiently effective approach in some situations, for other sensor network deployments involving large amounts of complex data it is more efficient for the sensor network application to process at least some of the data inside the mesh, saving on unnecessary data transmissions. However in the real world, the complexity of writing such an application in many cases precludes this from being created. An operating system that provides power-efficient distributed processing while presenting a more standard unified single system image to the application developer would provide new possibilities for sensor network application developers in terms of creating dynamic and complex sensor network applications. 

This thesis covers the design decisions, development process and evaluation of the Hydra distributed wireless sensor network operating system, an operating system that provides these services. The system is evaluated in the form of a scenario for monitoring intruders over a large area using accelerometer monitoring -- during this scenario, power efficiency is gained due to the intelligent Hydra operating system services, as the resulting accelerometer data is not moved across potentially multi-hop network links. Application code complexity is also reduced due to the higher-level single system image programming environment.

text: Distributed Operating Systems on Wireless Sensor Networks This thesis proposes the use of traditional distributed operating system and distributed systems techniques that are adapted and applied to the wireless sensor network domain. These techniques are applied to the creation of a wireless sensor network operating system that allows complex applications to be created without special programmer knowledge of sensor network programming or architecture. The resulting system is capable of executing a high level user application written in conventional single-system-image form, without the user being aware of the mesh architecture or underlying sensor node hardware.

A wireless sensor network is a collection of battery-powered embedded systems that communicate over low-bandwidth radio. Because of their limited hardware, niche deployments and use of embedded processors, programming techniques for wireless sensor network nodes are generally relatively esoteric compared to most software programming tasks. This can be relatively complex for programmers not familiar with the wireless sensor network domain. A naive approach to writing a wireless sensor network application may well result in considerably reduced battery life due to inefficient use of the limited power resources, requiring an expensive and time-consuming replacement or patching process. 

As a result of this complexity, traditional wireless sensor network applications are written as simply as possible. The majority of these applications simply move passive data readings back across a mesh to a more powerful server. While this is a sufficiently effective approach in some situations, for other sensor network deployments involving large amounts of complex data it is more efficient for the sensor network application to process at least some of the data inside the mesh, saving on unnecessary data transmissions. However in the real world, the complexity of writing such an application in many cases precludes this from being created. An operating system that provides power-efficient distributed processing while presenting a more standard unified single system image to the application developer would provide new possibilities for sensor network application developers in terms of creating dynamic and complex sensor network applications. 

This thesis covers the design decisions, development process and evaluation of the Hydra distributed wireless sensor network operating system, an operating system that provides these services. The system is evaluated in the form of a scenario for monitoring intruders over a large area using accelerometer monitoring -- during this scenario, power efficiency is gained due to the intelligent Hydra operating system services, as the resulting accelerometer data is not moved across potentially multi-hop network links. Application code complexity is also reduced due to the higher-level single system image programming environment.

year: 2017

title: Paradoxical mobilities: sharemilking with Te Raparahi Lands Trust (Wāotū)

authors: Hutcheson, Gail Yvonne

subjects: mobilities

abstract: Mobilities are important for capturing some of the combined movements of people, animals and objects in all of their complex relational dynamics. Sharemilking involves a cascade of mobilities: from the modest journies of the everyday to the upheaval of complete farm moves. Here we examine how sharemilkers are enabled and constrained in different ways by being mobile and landless, but also included are hopeful geographies. The sharemilker's mobile relationship to land, rather than ownership of it, works well with indigenous ideas of kaitiakitanga (guardianship) that is a central feature of multiply owned Māori land trust (Te Raparahi). Combining sharemilker mobility with te Raparahi, and importantly Ngāti Hūri historical and contemporary connections to Te Wāotū in South Waikato, Aotearoa New Zealand, reveals paradoxical mobilities of place.

text: Paradoxical mobilities: sharemilking with Te Raparahi Lands Trust (Wāotū) Mobilities are important for capturing some of the combined movements of people, animals and objects in all of their complex relational dynamics. Sharemilking involves a cascade of mobilities: from the modest journies of the everyday to the upheaval of complete farm moves. Here we examine how sharemilkers are enabled and constrained in different ways by being mobile and landless, but also included are hopeful geographies. The sharemilker's mobile relationship to land, rather than ownership of it, works well with indigenous ideas of kaitiakitanga (guardianship) that is a central feature of multiply owned Māori land trust (Te Raparahi). Combining sharemilker mobility with te Raparahi, and importantly Ngāti Hūri historical and contemporary connections to Te Wāotū in South Waikato, Aotearoa New Zealand, reveals paradoxical mobilities of place.

year: 2017