title: Reducing establishment rates of non-indigenous zooplankton in constructed waters

authors: Taylor, Claire Maree

subjects: non-indigenous zooplankton

abstract: Understanding the mechanisms that facilitate the establishment of non-indigenous species is imperative for devising techniques that will assist in reducing the establishment rates of non-indigenous species. The establishment non-indigenous species can have negative ecological, economic, and human health effects. Non-indigenous passively dispersing organisms such as zooplankton, have been reported to invade constructed lakes (e.g., dams, water supply reservoirs and ornamental ponds) at much faster rates than natural lakes. For example, in New Zealand, a high proportion constructed waters, including dams for hydroelectricity generation, ornamental ponds and disused mine pits, have been invaded by non-indigenous zooplankton, including a number of calanoid copepods that are seemingly currently confined to these habitats. This has lead to a number of theories that have attempted to explain what makes constructed water bodies more vulnerable to invasion than natural lakes. One common attribute of these water bodies is their relatively young age, leading to the assertion that low biotic resistance leads to higher vulnerability of zooplankton communities in early stages of development.
The aim of this study was to determine if seeding water bodies with sediments containing native zooplankton eggs in early stages of their development will accelerate community colonisation, leading to greater biotic resistance to subsequent establishment of new zooplankton species. Twenty outdoor tanks were filled with tap water, and nutrients added to provide eutrophic conditions. Sediments were added to all tanks. Ten treatment tanks contained sediments and associated diapausing zooplankton eggs, sourced from local water bodies. The sediments were autoclaved in the remaining ten, which acted as controls, and thus received zooplankton colonised via natural means only. Tanks were left to colonise for 12 months and community composition and environmental variables were regularly monitored. During the 12 month colonisation period, species richness increased to a mean of 4.6 species in the treatment tanks and 2.6 in control tanks. Community composition also rapidly diverged between control and treatment tanks. Treatment tanks acquired a greater proportion of species adapted to pelagic conditions, such as cladocerans and copepods, with control tanks generally acquiring a high proportion of small, littoral dwelling rotifers. New species were added at 12 months, comprising of two copepods, four rotifers, and one cladoceran species, which were not established in the tanks already. After the introduction of these species, the unseeded control tanks had a much higher proportion of establishment of the new species during the three month post-introduction period. For example, the non-indigenous calanoid copepod Skistodiaptomus pallidus established exclusively in tanks that were void of any other calanoid copepod species. These were primarily control tanks, suggesting that native calanoid copepods play a key role in reducing establishment rates of this taxon. At 12 months, when the new species were added, none of the environmental variables measured (temperature, chlorophyll a, conductivity, specific conductance, DO concentration, DO saturation and pH) were statistically different between treatment and control tanks. This infers that at the time the new species were introduced to the tanks, they experienced similar abiotic conditions, and environmental variability was therefore not responsible for the differing establishment rates.
This study proves that biotic resistance plays an important role in reducing the establishment rate of non-indigenous zooplankton. It also provides strong evidence that seeding constructed water bodies with sediments containing diapausing eggs from locally sourced communities can be used as an effective management tool to reduce establishment rates of non-indigenous zooplankton.

text: Reducing establishment rates of non-indigenous zooplankton in constructed waters Understanding the mechanisms that facilitate the establishment of non-indigenous species is imperative for devising techniques that will assist in reducing the establishment rates of non-indigenous species. The establishment non-indigenous species can have negative ecological, economic, and human health effects. Non-indigenous passively dispersing organisms such as zooplankton, have been reported to invade constructed lakes (e.g., dams, water supply reservoirs and ornamental ponds) at much faster rates than natural lakes. For example, in New Zealand, a high proportion constructed waters, including dams for hydroelectricity generation, ornamental ponds and disused mine pits, have been invaded by non-indigenous zooplankton, including a number of calanoid copepods that are seemingly currently confined to these habitats. This has lead to a number of theories that have attempted to explain what makes constructed water bodies more vulnerable to invasion than natural lakes. One common attribute of these water bodies is their relatively young age, leading to the assertion that low biotic resistance leads to higher vulnerability of zooplankton communities in early stages of development.
The aim of this study was to determine if seeding water bodies with sediments containing native zooplankton eggs in early stages of their development will accelerate community colonisation, leading to greater biotic resistance to subsequent establishment of new zooplankton species. Twenty outdoor tanks were filled with tap water, and nutrients added to provide eutrophic conditions. Sediments were added to all tanks. Ten treatment tanks contained sediments and associated diapausing zooplankton eggs, sourced from local water bodies. The sediments were autoclaved in the remaining ten, which acted as controls, and thus received zooplankton colonised via natural means only. Tanks were left to colonise for 12 months and community composition and environmental variables were regularly monitored. During the 12 month colonisation period, species richness increased to a mean of 4.6 species in the treatment tanks and 2.6 in control tanks. Community composition also rapidly diverged between control and treatment tanks. Treatment tanks acquired a greater proportion of species adapted to pelagic conditions, such as cladocerans and copepods, with control tanks generally acquiring a high proportion of small, littoral dwelling rotifers. New species were added at 12 months, comprising of two copepods, four rotifers, and one cladoceran species, which were not established in the tanks already. After the introduction of these species, the unseeded control tanks had a much higher proportion of establishment of the new species during the three month post-introduction period. For example, the non-indigenous calanoid copepod Skistodiaptomus pallidus established exclusively in tanks that were void of any other calanoid copepod species. These were primarily control tanks, suggesting that native calanoid copepods play a key role in reducing establishment rates of this taxon. At 12 months, when the new species were added, none of the environmental variables measured (temperature, chlorophyll a, conductivity, specific conductance, DO concentration, DO saturation and pH) were statistically different between treatment and control tanks. This infers that at the time the new species were introduced to the tanks, they experienced similar abiotic conditions, and environmental variability was therefore not responsible for the differing establishment rates.
This study proves that biotic resistance plays an important role in reducing the establishment rate of non-indigenous zooplankton. It also provides strong evidence that seeding constructed water bodies with sediments containing diapausing eggs from locally sourced communities can be used as an effective management tool to reduce establishment rates of non-indigenous zooplankton.

year: 2010

title: Substantive and procedural legislation in the Philippines to combat webcam-related child sexual abuse

authors: Dizon, Michael

abstract: This chapter examines the criminal laws and procedural rules in the Philippines that apply to webcam or online child sexual abuse. It analyzes the relevant treaties, legislation and case law, particularly those relating to sexual offenses involving minors and cybercrime investigations. The chapter also tackles specific legal issues concerning the use of Sweetie 2.0 in combating webcam-related child sexual abuse including child pornography, cybersex, child sex tourism, entrapment, and criminal investigations in an online context. Based on the research, many of the sex-related crimes under Philippine law can be used to investigate and prosecute the sexual abuse and exploitation of real children and minors via webcam or other similar means or media. However, most of these crimes do not apply in the case of Sweetie 2.0 because they require as an essential element for their commission the involvement of a real child or minor victim. As such, the possible crimes that may be committed in relation to Sweetie 2.0 are limited to cybersex, attempted cybersex, grooming, and luring. Also, since the general rule is that criminal investigations can only conducted when a crime has been, is being or is about to be committed, Sweetie 2.0 can only be used in the first stance to investigate these four offenses.

text: Substantive and procedural legislation in the Philippines to combat webcam-related child sexual abuse This chapter examines the criminal laws and procedural rules in the Philippines that apply to webcam or online child sexual abuse. It analyzes the relevant treaties, legislation and case law, particularly those relating to sexual offenses involving minors and cybercrime investigations. The chapter also tackles specific legal issues concerning the use of Sweetie 2.0 in combating webcam-related child sexual abuse including child pornography, cybersex, child sex tourism, entrapment, and criminal investigations in an online context. Based on the research, many of the sex-related crimes under Philippine law can be used to investigate and prosecute the sexual abuse and exploitation of real children and minors via webcam or other similar means or media. However, most of these crimes do not apply in the case of Sweetie 2.0 because they require as an essential element for their commission the involvement of a real child or minor victim. As such, the possible crimes that may be committed in relation to Sweetie 2.0 are limited to cybersex, attempted cybersex, grooming, and luring. Also, since the general rule is that criminal investigations can only conducted when a crime has been, is being or is about to be committed, Sweetie 2.0 can only be used in the first stance to investigate these four offenses.

year: 2019

title: Factors of desistance in violent offenders: Interpretative phenomenological analysis of the Tai Aroha programme

authors: Beattie, Christopher James

subjects: Desistance

abstract: The phenomenon of desistance from crime is central to the process of rehabilitation. This study examines desistance narratives from the Tai Aroha programme to identify the aspects of participation in a community-based special treatment unit that are effective from the perspective of participants. A review of desistance literature is presented in a New Zealand context. Interpretative phenomenological analysis was used to present common themes in 64 exit interviews of individuals who completed this programme over a period of 6 years. These themes were compared to the factors of desistance identified in the literature review. The three key concepts that emerged from this study as factors of desistance evident in the Tai Aroha programme were the Morphic Self, Family and Whanau, and Mindfulness. The concept of the Morphic Self is a perspective on the process of identity change as experienced by participants, and is a key product of this research. Three other factors were identified as prerequisites for successful completion of the programme that also therefore contribute to desistance: Motivation, Sobriety, and Peers and Support. Also identified from this research were aspects of the experience termed Elements of Influence, which are the facets of the participants, the programme and the interactions between the two that can be considered in order to improve the delivery of the programme and therefore promote desistance. A distinctive quality of the Tai Aroha programme that was influential in the successful promotion of desistance was its strong commitment to tikanga Māori and the incorporation of these cultural values into the lifestyle and therapeutic approaches adopted by the facilitators.

text: Factors of desistance in violent offenders: Interpretative phenomenological analysis of the Tai Aroha programme The phenomenon of desistance from crime is central to the process of rehabilitation. This study examines desistance narratives from the Tai Aroha programme to identify the aspects of participation in a community-based special treatment unit that are effective from the perspective of participants. A review of desistance literature is presented in a New Zealand context. Interpretative phenomenological analysis was used to present common themes in 64 exit interviews of individuals who completed this programme over a period of 6 years. These themes were compared to the factors of desistance identified in the literature review. The three key concepts that emerged from this study as factors of desistance evident in the Tai Aroha programme were the Morphic Self, Family and Whanau, and Mindfulness. The concept of the Morphic Self is a perspective on the process of identity change as experienced by participants, and is a key product of this research. Three other factors were identified as prerequisites for successful completion of the programme that also therefore contribute to desistance: Motivation, Sobriety, and Peers and Support. Also identified from this research were aspects of the experience termed Elements of Influence, which are the facets of the participants, the programme and the interactions between the two that can be considered in order to improve the delivery of the programme and therefore promote desistance. A distinctive quality of the Tai Aroha programme that was influential in the successful promotion of desistance was its strong commitment to tikanga Māori and the incorporation of these cultural values into the lifestyle and therapeutic approaches adopted by the facilitators.

year: 2018