title: Ecological values of Hamilton urban streams (North Island, New Zealand): constraints and opportunities for restoration

authors: Collier, Kevin J.

subjects: biodiversity

abstract: Urban streams globally are characterised by degraded habitat conditions and low aquatic biodiversity, but are increasingly becoming the focus of restoration activities. We investigated habitat quality, ecological function, and fish and macroinvertebrate community composition of gully streams in Hamilton City, New Zealand, and compared these with a selection of periurban sites surrounded by rural land. A similar complement of fish species was found at urban and periurban sites, including two threatened species, with only one introduced fish widespread (Gambusia affinis). Stream macroinvertebrate community metrics indicated low ecological condition at most urban and periurban sites, but highlighted the presence of one high value urban site with a fauna dominated by sensitive taxa. Light-trapping around seepages in city gullies revealed the presence of several caddisfly species normally associated with native forest, suggesting that seepage habitats can provide important refugia for some aquatic insects in urban environments. Qualitative measures of stream habitat were not significantly different between urban and periurban sites, but urban streams had significantly lower hydraulic function and higher biogeochemical function than periurban streams. These functional differences are thought to reflect, respectively, (1) the combined effects of channel modification and stormwater hydrology, and (2) the influence of riparian vegetation providing shade and enhancing habitat in streams. Significant relationships between some macroinvertebrate community metrics and riparian vegetation buffering and bank protection suggest that riparian enhancement may have beneficial ecological outcomes in some urban streams. Other actions that may contribute to urban stream restoration goals include an integrated catchment approach to resolving fish passage issues, active reintroduction of wood to streams to enhance cover and habitat heterogeneity, and seeding of depauperate streams with native migratory fish to help initiate natural recolonisation.

text: Ecological values of Hamilton urban streams (North Island, New Zealand): constraints and opportunities for restoration Urban streams globally are characterised by degraded habitat conditions and low aquatic biodiversity, but are increasingly becoming the focus of restoration activities. We investigated habitat quality, ecological function, and fish and macroinvertebrate community composition of gully streams in Hamilton City, New Zealand, and compared these with a selection of periurban sites surrounded by rural land. A similar complement of fish species was found at urban and periurban sites, including two threatened species, with only one introduced fish widespread (Gambusia affinis). Stream macroinvertebrate community metrics indicated low ecological condition at most urban and periurban sites, but highlighted the presence of one high value urban site with a fauna dominated by sensitive taxa. Light-trapping around seepages in city gullies revealed the presence of several caddisfly species normally associated with native forest, suggesting that seepage habitats can provide important refugia for some aquatic insects in urban environments. Qualitative measures of stream habitat were not significantly different between urban and periurban sites, but urban streams had significantly lower hydraulic function and higher biogeochemical function than periurban streams. These functional differences are thought to reflect, respectively, (1) the combined effects of channel modification and stormwater hydrology, and (2) the influence of riparian vegetation providing shade and enhancing habitat in streams. Significant relationships between some macroinvertebrate community metrics and riparian vegetation buffering and bank protection suggest that riparian enhancement may have beneficial ecological outcomes in some urban streams. Other actions that may contribute to urban stream restoration goals include an integrated catchment approach to resolving fish passage issues, active reintroduction of wood to streams to enhance cover and habitat heterogeneity, and seeding of depauperate streams with native migratory fish to help initiate natural recolonisation.

year: 2009

title: The Effect of Aqueous Urea on the Processing, Structure and Properties of CGM

authors: Pickering, Kim L.

subjects: corn gluten meal

abstract: Corn gluten meal (CGM) is potentially a cost-effective raw material for producing a bioderivable thermoplastic. However, CGM disintegrates to a powder subsequent to processing with polar plasticisers, such as water. The hypothesis of this study was that aqueous urea could be used to denature protein within CGM and therefore encourage protein–protein interactions leading to consolidated bioplastics when using water as a plasticiser. To assess this, the effects of aqueous urea on structure and properties of CGM with particular focus on storage were assessed. Processing of CGM with aqueous urea produced consolidated materials. FTIR analysis showed secondary structure was modified during processing, leading to increased amounts of α-helices and random coils and reduction of the amount of intermolecular β-sheets and turns. Above 6 wt% free water, the plasticising efficiency of water in processed CGM increased as the amount of denatured proteins increased. Below 6 wt% free water, protein secondary structure did not have a significant influence on thermal and flexural properties. It was found that storage environment and urea concentration influenced the rate of drying, however, the final water content was constant relative to CGM, and not urea. The materials were resistant to cracking at urea concentrations above 8 M, provided the mass loss during storage did not exceed 15 wt%.

text: The Effect of Aqueous Urea on the Processing, Structure and Properties of CGM Corn gluten meal (CGM) is potentially a cost-effective raw material for producing a bioderivable thermoplastic. However, CGM disintegrates to a powder subsequent to processing with polar plasticisers, such as water. The hypothesis of this study was that aqueous urea could be used to denature protein within CGM and therefore encourage protein–protein interactions leading to consolidated bioplastics when using water as a plasticiser. To assess this, the effects of aqueous urea on structure and properties of CGM with particular focus on storage were assessed. Processing of CGM with aqueous urea produced consolidated materials. FTIR analysis showed secondary structure was modified during processing, leading to increased amounts of α-helices and random coils and reduction of the amount of intermolecular β-sheets and turns. Above 6 wt% free water, the plasticising efficiency of water in processed CGM increased as the amount of denatured proteins increased. Below 6 wt% free water, protein secondary structure did not have a significant influence on thermal and flexural properties. It was found that storage environment and urea concentration influenced the rate of drying, however, the final water content was constant relative to CGM, and not urea. The materials were resistant to cracking at urea concentrations above 8 M, provided the mass loss during storage did not exceed 15 wt%.

year: 2012-06

title: Proposing an indigenous power of veto in Aotearoa New Zealand

authors: Te Aho, Linda

abstract: Tom Fookes was an architect of New Zealand's Resource Management Act passed in 1991 (RMA). When interviewed about his life's work, Tom responded that he had sought to create a 'fair, integrated consideration of the decisions and policy to do with the social, economic and environmental conditions of our people'. I am told that he worked hard to provide a fair opportunity for all people to have a voice in decisions that affect them and places they care about. Processes were included in the RMA to allow this to occur, with particular provisions for a distinctive Maori voice. Because of these provisions, and the Act's lodestar of sustainable resource management, the RMA was promoted as one of the 'world's finest national environmental policies'.

text: Proposing an indigenous power of veto in Aotearoa New Zealand Tom Fookes was an architect of New Zealand's Resource Management Act passed in 1991 (RMA). When interviewed about his life's work, Tom responded that he had sought to create a 'fair, integrated consideration of the decisions and policy to do with the social, economic and environmental conditions of our people'. I am told that he worked hard to provide a fair opportunity for all people to have a voice in decisions that affect them and places they care about. Processes were included in the RMA to allow this to occur, with particular provisions for a distinctive Maori voice. Because of these provisions, and the Act's lodestar of sustainable resource management, the RMA was promoted as one of the 'world's finest national environmental policies'.

year: 2015