title: Temporal and spatial variations of cyanobacteria in Karori Reservoir, Wellington

authors: Prentice, Matthew James

subjects: Perca fluviatilis

abstract: The Lower Karori Reservoir (LKR) is a small, monomictic lake of 2.34 ha situated in the Karori Wildlife Sanctuary (KWS), Wellington.  Over the past decade cyanobacterial blooms have become a common occurrence in this water body.  In 2005 Anabaena planktonica was detected for the first time in the LKR and this species now forms dense blooms during summer.  These blooms are problematic as they reduce aesthetic appeal and have resulted in odour problems for visitors to this high profile wildlife sanctuary.  The objectives of this study were to identify key physical, chemical and biological variables influencing phytoplankton dynamics in the LKR and to use ecological models to investigate plausible management options.  The key parameters investigated, that may cause bloom formation were; summer stratification, high nutrient levels, and the food web effects of a large population of European perch (Perca fluviatilis). 

High resolution sampling was carried out every six hours over a 72 hour period during pre-bloom, bloom and post-bloom periods in 2006/7 to elucidate short term temporal and spatial variations in biological and physico-chemical parameters.  Quantitative polymerase chain reaction (QPCR) was used to enumerate A. planktonica populations, allowing a large number of samples to be simultaneously evaluated.  Algal densities were also estimated using conventional phytoplankton enumeration and chlorophyll a analysis.  Water samples were collected for nutrient analysis at discrete depths and profiles were taken for temperature, dissolved oxygen and photosynthetic active radiation.  Secchi depth and pH were also measured.  Weekly or fortnightly phytoplankton and zooplankton samples and physical variables have been collected at LKR since September 2005 as part of an independent sampling program carried out by the KWS, Waikato University and Cawthron Institute.  In this project the 2-year data set was used to assist with analysis of lake processes and for validation of the hydrodynamic-ecological model DYRESM-CAEDYM.  Between 12 and 15 February, 2007, electric fishing was undertaken within the LKR.  A total of 3,946 P. fluviatilis were removed and the effects on phytoplankton and zooplankton concentrations were investigated.  To increase knowledge of the physiology of A. planktonica, laboratory experiments were undertaken using cultures subjected to a range of different light intensities and temperature regimes 

The phytoplankton assemblage of the LKR shows very distinct temporal variations.  Summer stratification occurred in the LKR for ~4 months each summer.  During these periods A. planktonica comprised up to 99.9% of the surface phytoplankton population.  During isothermy chlorophytes, bacillariophytes and small flagellated dinophytes are co-dominant in the phytoplankton assemblage.  The results of the QPCR showed distinct diurnal vertical movement of A. planktonica, with the highest cell concentrations occurring at 1900 hours at the surface.  Ammonium (NH4-N) is the dominant species of inorganic nitrogen during periods of stratification, while nitrate (NO3-N) is generally dominant during times of isothermy.  Phosphate concentrations at surface and depth remained at low levels throughout the sampling period.  The large surface populations of A. planktonica, are probably responsible for the elevated total nitrogen concentrations in surface waters during stratified periods.  There appeared to be some short term effects of the P. fluviatilis removal with an increase in large crustaceans (e.g., Daphnia sp.) and a reduction in A. planktonica densities observed in the months following the P. fluviatilis removal.  Only a small proportion of the total P. fluviatilis population was removed and it is unlikely that the effects will be long-lasting without subsequent removal steps. However, it seems likely that P. fluviatilis is one of the factors contributing to cyanobacterial blooms and management of this fish species should be considered in future lake restoration plans.  Growth experiments indicated A. planktonica grow over a wide range of light intensities and temperatures, although highest growth rates were generally associated with higher temperatures (25  C) and light intensities (60 - 140 μmol m-2 s-1).

Ecological and hydrodynamic trends within the LKR over a two year period were simulated with adequate success using the model DYRESM-CAEDYM.  Management scenarios simulated using DYRESM-CAEDYM suggest implementation of an artificial destratification system in the LKR may be the most practical and effective means of controlling A. planktonica blooms.  The addition of an artificial aeration system emitting air at a rate of approximately 50 l-1 s-1 should result in an isothermal system.  Without summer stratification some of the physiological features of A. planktonica (e.g., buoyancy regulation and nitrogen-fixation) that give it a competitive advantage over other phytoplankton species will be reduced.

text: Temporal and spatial variations of cyanobacteria in Karori Reservoir, Wellington The Lower Karori Reservoir (LKR) is a small, monomictic lake of 2.34 ha situated in the Karori Wildlife Sanctuary (KWS), Wellington.  Over the past decade cyanobacterial blooms have become a common occurrence in this water body.  In 2005 Anabaena planktonica was detected for the first time in the LKR and this species now forms dense blooms during summer.  These blooms are problematic as they reduce aesthetic appeal and have resulted in odour problems for visitors to this high profile wildlife sanctuary.  The objectives of this study were to identify key physical, chemical and biological variables influencing phytoplankton dynamics in the LKR and to use ecological models to investigate plausible management options.  The key parameters investigated, that may cause bloom formation were; summer stratification, high nutrient levels, and the food web effects of a large population of European perch (Perca fluviatilis). 

High resolution sampling was carried out every six hours over a 72 hour period during pre-bloom, bloom and post-bloom periods in 2006/7 to elucidate short term temporal and spatial variations in biological and physico-chemical parameters.  Quantitative polymerase chain reaction (QPCR) was used to enumerate A. planktonica populations, allowing a large number of samples to be simultaneously evaluated.  Algal densities were also estimated using conventional phytoplankton enumeration and chlorophyll a analysis.  Water samples were collected for nutrient analysis at discrete depths and profiles were taken for temperature, dissolved oxygen and photosynthetic active radiation.  Secchi depth and pH were also measured.  Weekly or fortnightly phytoplankton and zooplankton samples and physical variables have been collected at LKR since September 2005 as part of an independent sampling program carried out by the KWS, Waikato University and Cawthron Institute.  In this project the 2-year data set was used to assist with analysis of lake processes and for validation of the hydrodynamic-ecological model DYRESM-CAEDYM.  Between 12 and 15 February, 2007, electric fishing was undertaken within the LKR.  A total of 3,946 P. fluviatilis were removed and the effects on phytoplankton and zooplankton concentrations were investigated.  To increase knowledge of the physiology of A. planktonica, laboratory experiments were undertaken using cultures subjected to a range of different light intensities and temperature regimes 

The phytoplankton assemblage of the LKR shows very distinct temporal variations.  Summer stratification occurred in the LKR for ~4 months each summer.  During these periods A. planktonica comprised up to 99.9% of the surface phytoplankton population.  During isothermy chlorophytes, bacillariophytes and small flagellated dinophytes are co-dominant in the phytoplankton assemblage.  The results of the QPCR showed distinct diurnal vertical movement of A. planktonica, with the highest cell concentrations occurring at 1900 hours at the surface.  Ammonium (NH4-N) is the dominant species of inorganic nitrogen during periods of stratification, while nitrate (NO3-N) is generally dominant during times of isothermy.  Phosphate concentrations at surface and depth remained at low levels throughout the sampling period.  The large surface populations of A. planktonica, are probably responsible for the elevated total nitrogen concentrations in surface waters during stratified periods.  There appeared to be some short term effects of the P. fluviatilis removal with an increase in large crustaceans (e.g., Daphnia sp.) and a reduction in A. planktonica densities observed in the months following the P. fluviatilis removal.  Only a small proportion of the total P. fluviatilis population was removed and it is unlikely that the effects will be long-lasting without subsequent removal steps. However, it seems likely that P. fluviatilis is one of the factors contributing to cyanobacterial blooms and management of this fish species should be considered in future lake restoration plans.  Growth experiments indicated A. planktonica grow over a wide range of light intensities and temperatures, although highest growth rates were generally associated with higher temperatures (25  C) and light intensities (60 - 140 μmol m-2 s-1).

Ecological and hydrodynamic trends within the LKR over a two year period were simulated with adequate success using the model DYRESM-CAEDYM.  Management scenarios simulated using DYRESM-CAEDYM suggest implementation of an artificial destratification system in the LKR may be the most practical and effective means of controlling A. planktonica blooms.  The addition of an artificial aeration system emitting air at a rate of approximately 50 l-1 s-1 should result in an isothermal system.  Without summer stratification some of the physiological features of A. planktonica (e.g., buoyancy regulation and nitrogen-fixation) that give it a competitive advantage over other phytoplankton species will be reduced.

year: 2008

title: The uptake of artificial roosts by long-tailed bats (Chalinolobus tuberculatus) in Hamilton City

authors: Robinson, Hannah Lois

subjects: Long-tailed bat

abstract: Globally, short to medium-term mitigation for the loss of bat roosting habitat has largely favoured the implementation of artificial roosts. However, their implementation has somewhat outpaced research, resulting in highly generalised guidelines concerning installation, maintenance, and reported suitability. Large-scale infrastructure and urban development projects in New Zealand are increasingly occurring in recognised long-tailed bat (Chalinolobus tuberculatus) habitat. In 2019, to provide mitigation for the Southern Links Roading Project, 80 artificial roosts were installed in urban parks within Hamilton City. To better understand the uptake and suitability of artificial roosts for long-tailed bats. Research objectives included determination of artificial roost uptake and identification of specific areas of occupation or seasonal differences in occupation. In addition, seasonal acoustic bat surveys and mammalian predator surveys were conducted in ten locations within the vicinity of artificial roosts to determine their potential influence on roost uptake. Habitat surveys and geospatial analyses were also undertaken to understand what factors are important for artificial roost occupation, and if those factors can be used to reliably predict the probability of occupation. Twenty-four (31%) of the 76 monitored artificial roosts were observed as occupied by long-tailed bats. Occupation was largely infrequent, with no clear seasonal difference, or specific areas of occupation. Two triple-chambered boxes installed in 2012 in Sandford Park-A were the exception, with the number of roosting bats notably increasing over the summer maternity season. Areas with comparatively high bat activity (>50 bat passes/night) corresponded with a greater percentage of occupied artificial roosts. The prevalence of mammalian predators in urban parks connected to the Mangakotukuku Gully, was comparatively high with 50% of the chew track cards damaged by rats and possums each month, and at least one possum pass was recorded by camera traps per survey night. However, predator prevalence appeared to have little influence on artificial roost uptake due to the anti-predator bands on trees. General linear modelling indicated positive probability of roost occupation with increasing distance to stand edge, high canopy cover, and increasing terrain slope. This indicated that Hamilton City long-tailed bats prefer sheltered artificial roosts, installed further from the stand edge within landscape features such as gullies. The logistic model also identified that distance to stand edge was the only variable that could be used to reliably predict roost occupation. Positive probability of roost occupation with an increasing number of chambers indicated that bats prefer multichambered roosts that facilitate clustering, and the provision of a range of microclimatic conditions within the roost. Negative probability of roost occupation as distance to occupied roosts increased indicated that bats may prefer to roost in clusters of artificial roosts. Future artificial roost installation in Hamilton City should situate roosts in sheltered locations, ideally nearby natural or already occupied artificial roosts to facilitate discovery and uptake. Prior to installation, bat activity should be monitored so box installation can prioritise areas with high activity. Anti-predator band maintenance should also occur at least every 6-months to ensure bands have not detached, which may place roosting bats at risk of predation.

text: The uptake of artificial roosts by long-tailed bats (Chalinolobus tuberculatus) in Hamilton City Globally, short to medium-term mitigation for the loss of bat roosting habitat has largely favoured the implementation of artificial roosts. However, their implementation has somewhat outpaced research, resulting in highly generalised guidelines concerning installation, maintenance, and reported suitability. Large-scale infrastructure and urban development projects in New Zealand are increasingly occurring in recognised long-tailed bat (Chalinolobus tuberculatus) habitat. In 2019, to provide mitigation for the Southern Links Roading Project, 80 artificial roosts were installed in urban parks within Hamilton City. To better understand the uptake and suitability of artificial roosts for long-tailed bats. Research objectives included determination of artificial roost uptake and identification of specific areas of occupation or seasonal differences in occupation. In addition, seasonal acoustic bat surveys and mammalian predator surveys were conducted in ten locations within the vicinity of artificial roosts to determine their potential influence on roost uptake. Habitat surveys and geospatial analyses were also undertaken to understand what factors are important for artificial roost occupation, and if those factors can be used to reliably predict the probability of occupation. Twenty-four (31%) of the 76 monitored artificial roosts were observed as occupied by long-tailed bats. Occupation was largely infrequent, with no clear seasonal difference, or specific areas of occupation. Two triple-chambered boxes installed in 2012 in Sandford Park-A were the exception, with the number of roosting bats notably increasing over the summer maternity season. Areas with comparatively high bat activity (>50 bat passes/night) corresponded with a greater percentage of occupied artificial roosts. The prevalence of mammalian predators in urban parks connected to the Mangakotukuku Gully, was comparatively high with 50% of the chew track cards damaged by rats and possums each month, and at least one possum pass was recorded by camera traps per survey night. However, predator prevalence appeared to have little influence on artificial roost uptake due to the anti-predator bands on trees. General linear modelling indicated positive probability of roost occupation with increasing distance to stand edge, high canopy cover, and increasing terrain slope. This indicated that Hamilton City long-tailed bats prefer sheltered artificial roosts, installed further from the stand edge within landscape features such as gullies. The logistic model also identified that distance to stand edge was the only variable that could be used to reliably predict roost occupation. Positive probability of roost occupation with an increasing number of chambers indicated that bats prefer multichambered roosts that facilitate clustering, and the provision of a range of microclimatic conditions within the roost. Negative probability of roost occupation as distance to occupied roosts increased indicated that bats may prefer to roost in clusters of artificial roosts. Future artificial roost installation in Hamilton City should situate roosts in sheltered locations, ideally nearby natural or already occupied artificial roosts to facilitate discovery and uptake. Prior to installation, bat activity should be monitored so box installation can prioritise areas with high activity. Anti-predator band maintenance should also occur at least every 6-months to ensure bands have not detached, which may place roosting bats at risk of predation.

year: 2022

title: Kia rehe te matau, kia rehe te maui

authors: Winiata, Te Whatanui Huia

subjects: Taiaha, Maori business, maori development

abstract: The theory of applying successful military strategy to the world of business is not a new concept.  The connection between these two environments has often been explored, and works by Sun Tzu and others promote the connection between the battlefield and the boardroom.  The cut and thrust of the business realm is often likened to combat, and the guiding principles and beliefs that influence Generals and Field Commanders are in many ways identical to those of executives and Chief Executive Officers.

This thesis is interested in exploring the interconnectedness between battle and business from a Māori perspective.  In particular, this study explores the link between the Māori weapon known as the taiaha, and Māori business, in the belief that the lessons learnt from the various taiaha schools can be transferred to Māori business.  Likewise, the beliefs, principles and philosophies that are instilled within warriors while training with the taiaha have a valid place within Māori business, and when applied to the Māori business arena, have beneficial outcomes for those involved.

This study highlights fundamental taiaha principles that are applicable to the Māori business world.  These beliefs have been identified by a number of taiaha experts as well as successful Māori business operators.  The long term purpose of this thesis is to support Māori entering into business, by highlighting traditional values that are taught through the medium of taiaha, and showing how they can be applied to business.

text: Kia rehe te matau, kia rehe te maui The theory of applying successful military strategy to the world of business is not a new concept.  The connection between these two environments has often been explored, and works by Sun Tzu and others promote the connection between the battlefield and the boardroom.  The cut and thrust of the business realm is often likened to combat, and the guiding principles and beliefs that influence Generals and Field Commanders are in many ways identical to those of executives and Chief Executive Officers.

This thesis is interested in exploring the interconnectedness between battle and business from a Māori perspective.  In particular, this study explores the link between the Māori weapon known as the taiaha, and Māori business, in the belief that the lessons learnt from the various taiaha schools can be transferred to Māori business.  Likewise, the beliefs, principles and philosophies that are instilled within warriors while training with the taiaha have a valid place within Māori business, and when applied to the Māori business arena, have beneficial outcomes for those involved.

This study highlights fundamental taiaha principles that are applicable to the Māori business world.  These beliefs have been identified by a number of taiaha experts as well as successful Māori business operators.  The long term purpose of this thesis is to support Māori entering into business, by highlighting traditional values that are taught through the medium of taiaha, and showing how they can be applied to business.

year: 2013