title: Determining the age of paintings at JSARN–113/23, Jawoyn Country, central-western Arnhem Land plateau

authors: David, Bruno O.

abstract: Western Arnhem Land in northern Australia has the rare distinction, both at national and global scales, of containing a vast landscape of many thousands of rockshelters richly decorated with art, some of which was probably made tens of thousands of years ago, others as recently as a few decades ago. Yet the challenge remains as to how to date this art, how to find out how old it is. While relative dating methods have been commonly applied, in particular patterns of superimposition and changing faunal themes supposedly signalling changing environmental conditions, we still lack a clear understanding of the age of almost all the region’s art styles or conventions.
Other chapters in this volume report direct dates for Arnhem Land art using radiocarbon determinations on beeswax figures with the likelihood that the ‘art event’, the time when a beeswax figure was made, is at most a few years different from the ‘carbon event’, the time of the last biological capture of atmospheric carbon, which is the actual date measured by radiocarbon. But many, in fact most, sites have no beeswax figures or other ways directly to date the art. Sometimes, as again reported in this volume, there is some indication of date when a radiocarbon determination is obtained on, for instance, charcoal in an archaeological deposit that can be related to the art. Often that route is also blocked: many a painted surface without beeswax figures is in no close relation to a deposit that might so be dated. What can be done then?
Here we present results of investigations at a small rockshelter in Jawoyn Country, in the centralwestern part of the Arnhem Land plateau. Since its art cannot be directly dated, we follow a different path. In the first instance, we aim to understand the history, and antiquity, of the decorated rock surfaces, since the exposed surfaces of the boulder have undergone repeated transformations over a long time. Determining when now-decorated rock surfaces were formed can give us maximum possible ages for the art, since we can date when the surface first was available. Taken with related archaeological evidence from deposits, such as ochre fragments with signs of use, we can arrive at some indications for the age of the art, or at least how the range of possible dates is constrained. This approach is akin to that used at other sites in Jawoyn Country (see Chapters 11 and 15)

text: Determining the age of paintings at JSARN–113/23, Jawoyn Country, central-western Arnhem Land plateau Western Arnhem Land in northern Australia has the rare distinction, both at national and global scales, of containing a vast landscape of many thousands of rockshelters richly decorated with art, some of which was probably made tens of thousands of years ago, others as recently as a few decades ago. Yet the challenge remains as to how to date this art, how to find out how old it is. While relative dating methods have been commonly applied, in particular patterns of superimposition and changing faunal themes supposedly signalling changing environmental conditions, we still lack a clear understanding of the age of almost all the region’s art styles or conventions.
Other chapters in this volume report direct dates for Arnhem Land art using radiocarbon determinations on beeswax figures with the likelihood that the ‘art event’, the time when a beeswax figure was made, is at most a few years different from the ‘carbon event’, the time of the last biological capture of atmospheric carbon, which is the actual date measured by radiocarbon. But many, in fact most, sites have no beeswax figures or other ways directly to date the art. Sometimes, as again reported in this volume, there is some indication of date when a radiocarbon determination is obtained on, for instance, charcoal in an archaeological deposit that can be related to the art. Often that route is also blocked: many a painted surface without beeswax figures is in no close relation to a deposit that might so be dated. What can be done then?
Here we present results of investigations at a small rockshelter in Jawoyn Country, in the centralwestern part of the Arnhem Land plateau. Since its art cannot be directly dated, we follow a different path. In the first instance, we aim to understand the history, and antiquity, of the decorated rock surfaces, since the exposed surfaces of the boulder have undergone repeated transformations over a long time. Determining when now-decorated rock surfaces were formed can give us maximum possible ages for the art, since we can date when the surface first was available. Taken with related archaeological evidence from deposits, such as ochre fragments with signs of use, we can arrive at some indications for the age of the art, or at least how the range of possible dates is constrained. This approach is akin to that used at other sites in Jawoyn Country (see Chapters 11 and 15)

year: 2017

title: Exploring Education for Sustainable Development through Ship Youth Programmes: A Stakeholder Approach

authors: Castor, Richard Gavina

subjects: Education for Sustainable Development

abstract: Education for sustainable development (ESD) was explored through a stakeholder approach in the context of two ship youth programmes from an Asia-Pacific region perspective. Specifically, the research examined challenges and opportunities of holistically integrating ESD into an informal social learning setting. Utilising Skype, semi-structured interviews of the main stakeholders of the programme, triangulated with secondary sources provided the data for analysis of a qualitative, multiple case study. Results highlighted two identified themes reflecting the challenges and opportunities if ESD is to be incorporated into the ship youth programmes – stakeholder dynamics: stakeholder role and responsibility, diversity, social network building, investment and social capital; and complexities in understanding Sustainable Development: SD dimensions through discussion topics, language, concept and context, moving from awareness to action, sustainability reporting, standards, monitoring and evaluation mechanisms, and sustainable future from youths’ interest, commitment and vision. The ship youth programmes present an opportunity to embrace concepts entrenched in sustainable development and have an enormous potential to extend frameworks and aspects of action competence leading to education for a sustainable future.

text: Exploring Education for Sustainable Development through Ship Youth Programmes: A Stakeholder Approach Education for sustainable development (ESD) was explored through a stakeholder approach in the context of two ship youth programmes from an Asia-Pacific region perspective. Specifically, the research examined challenges and opportunities of holistically integrating ESD into an informal social learning setting. Utilising Skype, semi-structured interviews of the main stakeholders of the programme, triangulated with secondary sources provided the data for analysis of a qualitative, multiple case study. Results highlighted two identified themes reflecting the challenges and opportunities if ESD is to be incorporated into the ship youth programmes – stakeholder dynamics: stakeholder role and responsibility, diversity, social network building, investment and social capital; and complexities in understanding Sustainable Development: SD dimensions through discussion topics, language, concept and context, moving from awareness to action, sustainability reporting, standards, monitoring and evaluation mechanisms, and sustainable future from youths’ interest, commitment and vision. The ship youth programmes present an opportunity to embrace concepts entrenched in sustainable development and have an enormous potential to extend frameworks and aspects of action competence leading to education for a sustainable future.

year: 2014

title: Evaluating the effects of invasive brown bullhead catfish (Ameiurus nebulosus) on kōura (freshwater crayfish, Paranephrops planifrons) in Lake Rotoiti

authors: Francis, Laura Beverley

subjects: catfish

abstract: Brown bullhead catfish (Ameiurus nebulosus) are opportunistic carnivores native to North America and were first detected in Te Weta Bay, Lake Rotoiti, in March 2016. A cordon was placed across the bay to try and contain catfish, but they had already established populations elsewhere. Spread of catfish in the lake raised concern for resident populations of freshwater crayfish or kōura (Paranephrops planifrons), which are of ecological and cultural significance to Māori. Given the limited knowledge of the potential impacts of catfish on native biota, this thesis aims to evaluate the effects of catfish on kōura in Lake Rotoiti. To do this, Bay of Plenty Regional Council (BOPRC) routine fyke netting data was used to explore species trends and relationships. A habitat survey was also conducted using whakaweku (bracken fern bundles) and fyke nets, to generate data on species’ habitat preferences and kōura metrics (e.g., sizes and sex ratios). In addition to fishing, kōura and catfish stomachs were dissected to determine diet. Potential food items of catfish were also collected for stable isotope analysis to estimate dietary overlap between catfish and kōura, and long-term resource acquisition. 

Routine BOPRC fyke netting results indicated that kōura catch per unit effort (CPUE) has declined in Lake Rotoiti, with mean catch rates dropping from 10.6 kōura net-1 night-1 in 2016 to 4.2 kōura net-1 night-1 in 2018. Over the same period, catfish CPUE has increased in the lake, with the highest catch rates in Te Weta Bay, where mean catch rates have increased from 1.1 catfish net-1 night-1 in 2016 to 63.7 catfish net-1 night-1 in 2018. Catfish catch rates were negatively associated with catch rates of kōura (r = −0.180). Mean catfish density also had a significant effect on kōura catch rates, with significantly more kōura being caught at sites without catfish. The negative association between catfish and kōura could be due to catfish eating or competing with kōura, or their differing habitat preferences. Catfish were positively associated with sites that are weedy or muddy and kōura were negatively associated with muddy habitats and were positively associated with rocky habitats. Whakaweku set at shallow depths <1 m in the lake littoral zone were ineffective at catching kōura during the habitat survey. 

Catfish diet consisted largely of chironomid larvae (Chironomidae), detritus, common bullies (Gobiomorphus cotidianus), and to a lesser extent kōura. Kōura were found in 12% of large catfish (>200 mm fork length; FL) stomachs analysed and contributed 5% volumetrically to large catfish diet. Unfortunately, the contribution of kōura to catfish diet could not be established using stable isotopes because isotopic signatures of kōura and bullies were too close to differentiate. Kōura diet consisted primarily of animal remains (common bullies and invertebrates) and detritus. Stable isotopes of carbon and nitrogen revealed that diets of kōura and catfish overlapped, with kōura sharing more of their diet with catfish than vice versa, likely reflecting catfish’s broad diet. This study suggests that catfish are responsible for the recent decline in kōura CPUE in Lake Rotoiti and that catfish are directly and indirectly affecting kōura through predation and competition for shared food resources.

text: Evaluating the effects of invasive brown bullhead catfish (Ameiurus nebulosus) on kōura (freshwater crayfish, Paranephrops planifrons) in Lake Rotoiti Brown bullhead catfish (Ameiurus nebulosus) are opportunistic carnivores native to North America and were first detected in Te Weta Bay, Lake Rotoiti, in March 2016. A cordon was placed across the bay to try and contain catfish, but they had already established populations elsewhere. Spread of catfish in the lake raised concern for resident populations of freshwater crayfish or kōura (Paranephrops planifrons), which are of ecological and cultural significance to Māori. Given the limited knowledge of the potential impacts of catfish on native biota, this thesis aims to evaluate the effects of catfish on kōura in Lake Rotoiti. To do this, Bay of Plenty Regional Council (BOPRC) routine fyke netting data was used to explore species trends and relationships. A habitat survey was also conducted using whakaweku (bracken fern bundles) and fyke nets, to generate data on species’ habitat preferences and kōura metrics (e.g., sizes and sex ratios). In addition to fishing, kōura and catfish stomachs were dissected to determine diet. Potential food items of catfish were also collected for stable isotope analysis to estimate dietary overlap between catfish and kōura, and long-term resource acquisition. 

Routine BOPRC fyke netting results indicated that kōura catch per unit effort (CPUE) has declined in Lake Rotoiti, with mean catch rates dropping from 10.6 kōura net-1 night-1 in 2016 to 4.2 kōura net-1 night-1 in 2018. Over the same period, catfish CPUE has increased in the lake, with the highest catch rates in Te Weta Bay, where mean catch rates have increased from 1.1 catfish net-1 night-1 in 2016 to 63.7 catfish net-1 night-1 in 2018. Catfish catch rates were negatively associated with catch rates of kōura (r = −0.180). Mean catfish density also had a significant effect on kōura catch rates, with significantly more kōura being caught at sites without catfish. The negative association between catfish and kōura could be due to catfish eating or competing with kōura, or their differing habitat preferences. Catfish were positively associated with sites that are weedy or muddy and kōura were negatively associated with muddy habitats and were positively associated with rocky habitats. Whakaweku set at shallow depths <1 m in the lake littoral zone were ineffective at catching kōura during the habitat survey. 

Catfish diet consisted largely of chironomid larvae (Chironomidae), detritus, common bullies (Gobiomorphus cotidianus), and to a lesser extent kōura. Kōura were found in 12% of large catfish (>200 mm fork length; FL) stomachs analysed and contributed 5% volumetrically to large catfish diet. Unfortunately, the contribution of kōura to catfish diet could not be established using stable isotopes because isotopic signatures of kōura and bullies were too close to differentiate. Kōura diet consisted primarily of animal remains (common bullies and invertebrates) and detritus. Stable isotopes of carbon and nitrogen revealed that diets of kōura and catfish overlapped, with kōura sharing more of their diet with catfish than vice versa, likely reflecting catfish’s broad diet. This study suggests that catfish are responsible for the recent decline in kōura CPUE in Lake Rotoiti and that catfish are directly and indirectly affecting kōura through predation and competition for shared food resources.

year: 2019