title: Lakes water quality: Lake weed and pest animals

authors: Hon, Nick Smith

abstract: It is a pleasure to be invited to be part of this. The debate around fresh water in New Zealand has never been so strong and the delight in coming to Rotorua is that so many parts of New Zealand could learn from the experience here of pulling together a sciencebased collaborative approach for progress. Just listening to Professor David Hamilton's presentation, reinforcing how complex these fresh water issues are, signals the progress that has been achieved.

text: Lakes water quality: Lake weed and pest animals It is a pleasure to be invited to be part of this. The debate around fresh water in New Zealand has never been so strong and the delight in coming to Rotorua is that so many parts of New Zealand could learn from the experience here of pulling together a sciencebased collaborative approach for progress. Just listening to Professor David Hamilton's presentation, reinforcing how complex these fresh water issues are, signals the progress that has been achieved.

year: 2017

title: Production and decay of mangrove (Avicennia marina subsp. australasica) detritus and its effects on coastal benthic communities

authors: Gladstone-Gallagher, Rebecca

subjects: Macrobenthic assemblages

abstract: Temperate mangrove forests have been poorly studied compared to their tropical counterparts, because they constitute just 1.4% of the global mangrove forest area. Research from tropical mangrove forests suggests they are open systems that provide a large array of ecosystem goods and services. For example, tropical mangrove forests frequently support invertebrate communities in adjacent habitats through the production, export, decomposition and uptake of organic matter. However, ecological differences between temperate and tropical mangrove forests means that information collected in tropical regions cannot be readily extrapolated to temperate systems. Therefore, it is unclear how, or if, temperate mangrove forests supply an organic subsidy to estuarine ecosystems. Here I investigate the linkages between mangrove organic matter production and the role that decomposing mangrove detritus (dead, broken down organic matter) plays in structuring estuarine benthic communities. Research was conducted at two sites (encompassing small-scale differences in sediment properties and macrofaunal communities) in Whangamata Harbour, New Zealand. The production of mangrove detritus was quantified by measuring litter production and its decomposition into detritus. A manipulative detritus addition experiment explored the role of exported mangrove detritus in structuring benthic communities of unvegetated intertidal flats.
 
The temperate Whangamata Harbour mangrove forest produced the equivalent of 3.24 - 5.38 t DW ha-1 yr-1 of litter, which is comparable to forests at similar latitudes and overlaps with the lower range of tropical mangrove productivity. The decomposition rates of litter following summer litterfall were dependent upon the type of litter, as well as the burial state. However, hypotheses that tidal position and site would affect litter degradation rates were not supported. Leaf and wood litter that was buried in the sediment decomposed significantly slower (1.3 - 1.4 times slower) than litter on the sediment surface. Leaf litter decomposition was faster (63 days to decay by 50%) than wood and root material (460 and 316 days, respectively). Decay models predicted that wood and root material will take years to breakdown, which has implications for New Zealand mangrove removal plans, where wood and roots often remain in situ (following clearances). Finally, a manipulative detrital addition experiment found that mangrove detritus created subtle changes in the relative abundances of a few dominant taxa, rather than shifts in whole community species composition. Communities responded similarly to the addition of mangrove detritus, with the same dominant taxa responding at both experimental sites. The subtle benthic community responses to the large amount of detritus added suggests that mangrove detritus plays a relatively minor role in shaping communities on temperate intertidal flats. The studies that comprise this thesis have together shown that as a result of different input and decomposition rates of mangrove litter, temperate estuarine benthic communities are probably less reliant on mangrove productivity than tropical communities.

text: Production and decay of mangrove (Avicennia marina subsp. australasica) detritus and its effects on coastal benthic communities Temperate mangrove forests have been poorly studied compared to their tropical counterparts, because they constitute just 1.4% of the global mangrove forest area. Research from tropical mangrove forests suggests they are open systems that provide a large array of ecosystem goods and services. For example, tropical mangrove forests frequently support invertebrate communities in adjacent habitats through the production, export, decomposition and uptake of organic matter. However, ecological differences between temperate and tropical mangrove forests means that information collected in tropical regions cannot be readily extrapolated to temperate systems. Therefore, it is unclear how, or if, temperate mangrove forests supply an organic subsidy to estuarine ecosystems. Here I investigate the linkages between mangrove organic matter production and the role that decomposing mangrove detritus (dead, broken down organic matter) plays in structuring estuarine benthic communities. Research was conducted at two sites (encompassing small-scale differences in sediment properties and macrofaunal communities) in Whangamata Harbour, New Zealand. The production of mangrove detritus was quantified by measuring litter production and its decomposition into detritus. A manipulative detritus addition experiment explored the role of exported mangrove detritus in structuring benthic communities of unvegetated intertidal flats.
 
The temperate Whangamata Harbour mangrove forest produced the equivalent of 3.24 - 5.38 t DW ha-1 yr-1 of litter, which is comparable to forests at similar latitudes and overlaps with the lower range of tropical mangrove productivity. The decomposition rates of litter following summer litterfall were dependent upon the type of litter, as well as the burial state. However, hypotheses that tidal position and site would affect litter degradation rates were not supported. Leaf and wood litter that was buried in the sediment decomposed significantly slower (1.3 - 1.4 times slower) than litter on the sediment surface. Leaf litter decomposition was faster (63 days to decay by 50%) than wood and root material (460 and 316 days, respectively). Decay models predicted that wood and root material will take years to breakdown, which has implications for New Zealand mangrove removal plans, where wood and roots often remain in situ (following clearances). Finally, a manipulative detrital addition experiment found that mangrove detritus created subtle changes in the relative abundances of a few dominant taxa, rather than shifts in whole community species composition. Communities responded similarly to the addition of mangrove detritus, with the same dominant taxa responding at both experimental sites. The subtle benthic community responses to the large amount of detritus added suggests that mangrove detritus plays a relatively minor role in shaping communities on temperate intertidal flats. The studies that comprise this thesis have together shown that as a result of different input and decomposition rates of mangrove litter, temperate estuarine benthic communities are probably less reliant on mangrove productivity than tropical communities.

year: 2012

title: Dying to research: An autoethnographic exploration of researching Māori and whānau experiences of end-of-life care

authors: Moeke-Maxwell, Tess

subjects: indigenous

abstract: The authors critically reflect on the autoethnographic process involved in navigating a smooth pathway towards investigating dying, death and bereavement for Māori whānau (families) in a way that supports and gives voice to their experience. This study, based in the Māori & Psychology Research Unit at The University of Waikato, is supported by a Health Research Council Erihapeti Rehu-Murchie Career Development Award. It explores the “end-of-life” journeys of Māori and their whānau in South Auckland and Waikato, through the dying process and subsequent challenges of bereavement. The researcher’s journey from novice to someone fully enmeshed in the struggles and triumphs of conducting research with Māori is examined. There is reflection on the challenges and issues that have emerged since settling on this research topic. These include ethical concerns, and the processes and outcomes associated with negotiating tensions between a shifting academic objectivity and the development of a methodology requiring subjective reflexivity.

text: Dying to research: An autoethnographic exploration of researching Māori and whānau experiences of end-of-life care The authors critically reflect on the autoethnographic process involved in navigating a smooth pathway towards investigating dying, death and bereavement for Māori whānau (families) in a way that supports and gives voice to their experience. This study, based in the Māori & Psychology Research Unit at The University of Waikato, is supported by a Health Research Council Erihapeti Rehu-Murchie Career Development Award. It explores the “end-of-life” journeys of Māori and their whānau in South Auckland and Waikato, through the dying process and subsequent challenges of bereavement. The researcher’s journey from novice to someone fully enmeshed in the struggles and triumphs of conducting research with Māori is examined. There is reflection on the challenges and issues that have emerged since settling on this research topic. These include ethical concerns, and the processes and outcomes associated with negotiating tensions between a shifting academic objectivity and the development of a methodology requiring subjective reflexivity.

year: 2010