title: How low can they go: A comparison between dog (Canis familiaris) and environmental DNA detection of invasive koi carp (Cyprinus rubrofuscus)

authors: Collins, Melissa Anne

subjects: scent detection dogs

abstract: Carp (Cyprinus sp.) are a highly invasive fish that pose a significant threat to freshwater ecosystems worldwide. At high biomasses (i.e., ≥100 kg/ha), the benthic feeding behaviour of carp can have deleterious ecosystem effects, often changing clear, macrophyte dominant waterbodies to turbid-phytoplankton dominant ecosystems. To prevent carp from reaching ecologically harmful biomasses, early detection (i.e., before population establishment) and rapid control actions are vital. Boat electrofishing, netting, and environmental DNA (eDNA) are commonly used to survey for carp, but these methods can be expensive or time inefficient when fish densities are low. Scent-detection dogs have proven efficacious at detecting terrestrial and aquatic species and could represent an efficient method for early detection of carp invasions. Here, we investigated a dog’s sensitivity and specificity to carp scent using a multiple probe design experiment. The dog was trained to use an automated carousel independently of its handler and assessed water samples from aquaria containing either no fish scent (n = 3, nontarget), goldfish (Carassius auratus) scent (n = 5, non-target) or carp scent (n = 9, target). The goldfish samples and six of the target samples were presented to the dog at a standard fish biomass concentration of 15.5 mg/L. The remaining three target samples (probes) were systematically diluted to determine the dog’s detection threshold. Results showed that the dog could detect carp housed under laboratory conditions down to a dilution equivalent biomass of 9.3 kg/ha (i.e., 0.5 mg carp/L), which is well below the likely biomass threshold of carp known to cause significant ecological impacts. The dog’s scent-detection performance was then compared with eDNA, an existing survey method. Quantitative PCR conducted on DNA extracted from laboratory aquaria filtrate revealed that the species-specific primer could detect carp at 9.3 kg/ha, but amplification rates at this dilution were low, as were all dilutions below the limit of quantification (≈160 kg/ha). These findings suggest that dogs could provide an accurate and highly sensitive method invasive fish detection. However, before deployment as a carp surveillance method, dogs’ performance on water samples collected from natural aquatic systems (i.e., lakes, ponds, rivers) needs to be evaluated. To our knowledge this is the first published study of its kind comparing a dog’s sensitivity to eDNA, and investigating the potential utility of dogs as an invasive fish detection method.

text: How low can they go: A comparison between dog (Canis familiaris) and environmental DNA detection of invasive koi carp (Cyprinus rubrofuscus) Carp (Cyprinus sp.) are a highly invasive fish that pose a significant threat to freshwater ecosystems worldwide. At high biomasses (i.e., ≥100 kg/ha), the benthic feeding behaviour of carp can have deleterious ecosystem effects, often changing clear, macrophyte dominant waterbodies to turbid-phytoplankton dominant ecosystems. To prevent carp from reaching ecologically harmful biomasses, early detection (i.e., before population establishment) and rapid control actions are vital. Boat electrofishing, netting, and environmental DNA (eDNA) are commonly used to survey for carp, but these methods can be expensive or time inefficient when fish densities are low. Scent-detection dogs have proven efficacious at detecting terrestrial and aquatic species and could represent an efficient method for early detection of carp invasions. Here, we investigated a dog’s sensitivity and specificity to carp scent using a multiple probe design experiment. The dog was trained to use an automated carousel independently of its handler and assessed water samples from aquaria containing either no fish scent (n = 3, nontarget), goldfish (Carassius auratus) scent (n = 5, non-target) or carp scent (n = 9, target). The goldfish samples and six of the target samples were presented to the dog at a standard fish biomass concentration of 15.5 mg/L. The remaining three target samples (probes) were systematically diluted to determine the dog’s detection threshold. Results showed that the dog could detect carp housed under laboratory conditions down to a dilution equivalent biomass of 9.3 kg/ha (i.e., 0.5 mg carp/L), which is well below the likely biomass threshold of carp known to cause significant ecological impacts. The dog’s scent-detection performance was then compared with eDNA, an existing survey method. Quantitative PCR conducted on DNA extracted from laboratory aquaria filtrate revealed that the species-specific primer could detect carp at 9.3 kg/ha, but amplification rates at this dilution were low, as were all dilutions below the limit of quantification (≈160 kg/ha). These findings suggest that dogs could provide an accurate and highly sensitive method invasive fish detection. However, before deployment as a carp surveillance method, dogs’ performance on water samples collected from natural aquatic systems (i.e., lakes, ponds, rivers) needs to be evaluated. To our knowledge this is the first published study of its kind comparing a dog’s sensitivity to eDNA, and investigating the potential utility of dogs as an invasive fish detection method.

year: 2022

title: Runoff, infiltration and soil erodibility studies in the Otutira catchment

authors: Selby, Michael J.

abstract: Yellow-brown pumice soils cover a large area of the central North Island of New Zealand. In the Waikato River basin these soils occupy over 7,000km². Since land development started in the mid-1930s approximately 4,000km² have been converted from the native vegetation to exotic forests (1,243km²) and pasture (2,740km²), and a further 500km² could be developed.

Since about 1959 gully erosion has become more common and widespread. The causes of this erosion were not known, although many hypotheses attempting to account for erosion have been put forward. The research reported in this thesis was undertaken in an attempt to isolate the most important causes of erosion.

Three experiments have been completed.
(1) A study of runoff from plots placed in areas of pasture grass, ungrazed grass and scrub vegetation has been made. Climatic, soil, vegetation, and slope variables were studied and as a result of statistical analysis it is concluded that surface water runoff is greater from developed land in pasture and less from areas covered by scrub and ungrazed grass vegetation. The major causes of runoff from pastures are very intense rainfall on a soil with low moisture content.

(2) Infiltration studies with an infiltrometer, designed and built for the purpose, reinforce the conclusions drawn from runoff studies. They also show that modifications of soil properties, especially compaction caused by animals and vehicles, decrease infiltration and hence promote runoff.

(3) Flume studies of the erodibility of pumice soils indicate that soil particles are easily entrained by running water, but that plant roots inhibit this process. Analysis of data from the three experiments indicates that land development should be carried out so that: (a) a close vegetation cover is kept on all soils; (b) channel development is avoided; (c) vulnerable areas such as valley floors and steep valley sides are kept as water absorption areas; (d) animals and vehicles are excluded from water absorption areas to prevent soil compaction; (e) plants with strong and dense root systems are used to protect surface soils.

text: Runoff, infiltration and soil erodibility studies in the Otutira catchment Yellow-brown pumice soils cover a large area of the central North Island of New Zealand. In the Waikato River basin these soils occupy over 7,000km². Since land development started in the mid-1930s approximately 4,000km² have been converted from the native vegetation to exotic forests (1,243km²) and pasture (2,740km²), and a further 500km² could be developed.

Since about 1959 gully erosion has become more common and widespread. The causes of this erosion were not known, although many hypotheses attempting to account for erosion have been put forward. The research reported in this thesis was undertaken in an attempt to isolate the most important causes of erosion.

Three experiments have been completed.
(1) A study of runoff from plots placed in areas of pasture grass, ungrazed grass and scrub vegetation has been made. Climatic, soil, vegetation, and slope variables were studied and as a result of statistical analysis it is concluded that surface water runoff is greater from developed land in pasture and less from areas covered by scrub and ungrazed grass vegetation. The major causes of runoff from pastures are very intense rainfall on a soil with low moisture content.

(2) Infiltration studies with an infiltrometer, designed and built for the purpose, reinforce the conclusions drawn from runoff studies. They also show that modifications of soil properties, especially compaction caused by animals and vehicles, decrease infiltration and hence promote runoff.

(3) Flume studies of the erodibility of pumice soils indicate that soil particles are easily entrained by running water, but that plant roots inhibit this process. Analysis of data from the three experiments indicates that land development should be carried out so that: (a) a close vegetation cover is kept on all soils; (b) channel development is avoided; (c) vulnerable areas such as valley floors and steep valley sides are kept as water absorption areas; (d) animals and vehicles are excluded from water absorption areas to prevent soil compaction; (e) plants with strong and dense root systems are used to protect surface soils.

year: 1971

title: Kimihia, rangahaua ngā tikanga heke iho. He taonga huahua e riro mai: Exploring whakapapa as a tool towards a kaupapa Māori assessment framework in early childhood education

authors: Paki, Vanessa Anne

subjects: kaupapa Maori assessment

abstract: This study explores whakapapa as a tool, which can be used as a kaupapa Māori assessment framework in early childhood education, positioning kaupapa Māori theory as a paradigm base underpinning a philosophical and theoretical discourse towards assessment for children's learning. This thesis represents the culmination of a personal and professional journey, derived from the writer's longstanding interest in and commitment to kaupapa Māori early childhood education, and more specifically, philosophies and practices for assessment in this context. The study has canvassed a vast terrain of kaupapa Māori philosophy in its search for a theoretical grounding for a kaupapa Māori assessment framework for early childhood education.
Foundation to the study has been the premise that the notion of whakapapa serves as an overarching philosophical matrix, encompassing the interconnected realms of genealogy, spirituality, and knowledge that precede, surround, and embrace the Māori child. Throughout the thesis, diagrams are employed to demonstrate and model the whakapapa underpinning the conceptualisations being explored. After contextualising the study within a historical overview of the impact of colonisation of kaupapa Māori education and research, it is suggested that a re-examination of key concepts from tikanga Māori will illuminate transformative possibilities applicable to the study's focus on the development of a theoretical base for an assessment tool within kaupapa Māori early childhood settings. Drawing from the literature, the thesis re-positions the view of the Māori child to one of being nurtured within a philosophical construct underpinned and immersed in tikanga such as whakapapa, ira tangata, whanaungatanga, mana and tapu, and ako, providing a strongly Māori theoretical base for the envisioning of the assessment process. The outcome of this study is to propose an assessment framework, which embodies and reflects these core kaupapa Māori philosophies as praxis.

text: Kimihia, rangahaua ngā tikanga heke iho. He taonga huahua e riro mai: Exploring whakapapa as a tool towards a kaupapa Māori assessment framework in early childhood education This study explores whakapapa as a tool, which can be used as a kaupapa Māori assessment framework in early childhood education, positioning kaupapa Māori theory as a paradigm base underpinning a philosophical and theoretical discourse towards assessment for children's learning. This thesis represents the culmination of a personal and professional journey, derived from the writer's longstanding interest in and commitment to kaupapa Māori early childhood education, and more specifically, philosophies and practices for assessment in this context. The study has canvassed a vast terrain of kaupapa Māori philosophy in its search for a theoretical grounding for a kaupapa Māori assessment framework for early childhood education.
Foundation to the study has been the premise that the notion of whakapapa serves as an overarching philosophical matrix, encompassing the interconnected realms of genealogy, spirituality, and knowledge that precede, surround, and embrace the Māori child. Throughout the thesis, diagrams are employed to demonstrate and model the whakapapa underpinning the conceptualisations being explored. After contextualising the study within a historical overview of the impact of colonisation of kaupapa Māori education and research, it is suggested that a re-examination of key concepts from tikanga Māori will illuminate transformative possibilities applicable to the study's focus on the development of a theoretical base for an assessment tool within kaupapa Māori early childhood settings. Drawing from the literature, the thesis re-positions the view of the Māori child to one of being nurtured within a philosophical construct underpinned and immersed in tikanga such as whakapapa, ira tangata, whanaungatanga, mana and tapu, and ako, providing a strongly Māori theoretical base for the envisioning of the assessment process. The outcome of this study is to propose an assessment framework, which embodies and reflects these core kaupapa Māori philosophies as praxis.

year: 2007