Charophytes of Australia’s Northern Territory – I. Tribe Chareae
- Casanova, Michelle, Karol, Kenneth
- Authors: Casanova, Michelle , Karol, Kenneth
- Date: 2023
- Type: Text , Journal article
- Relation: Australian Systematic Botany Vol. 36, no. 1 (2023), p. 38-79
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- Description: This study of Northern Territory charophytes documents 22 species in 3 of the genera in tribe Chareae, family Characeae, including 15 previously described species (Chara benthamii, C. erythrogyna, C. globularis, C. karolii, C. lucida, C. porteri, C. protocharoides, C. setosa, C. submollusca, C. wightii, C. zeylanica, Lamprothamnium capitatum, L. compactum, L. stipitatum, Lychnothamnus barbatus) of which 2 are new for the Australian flora (C. erythrogyna and C. wightii), as well as 5 varieties raised to species rank (C. aridicola, C. arnhemensis, C. bancroftii, C. behriana, C. duriuscula), and 2 newly described species (C. lamprothamniformis, C. schultae). Three previously reported species in the tribe (C. braunii, C. corallina, C. fibrosa) are not recorded from the Northern Territory in this study, as previous records were based on erroneous identifications or localities. Although Northern Territory specimens of Lychnothamnus barbatus have not been seen, it has been included in this treatment, because it occurs in south-eastern Queensland, the Gulf of Carpentaria, Papua New Guinea and Timor-Leste. A key, illustrations and descriptions of all the species are provided.
- Authors: Casanova, Michelle , Karol, Kenneth
- Date: 2023
- Type: Text , Journal article
- Relation: Australian Systematic Botany Vol. 36, no. 1 (2023), p. 38-79
- Full Text:
- Reviewed:
- Description: This study of Northern Territory charophytes documents 22 species in 3 of the genera in tribe Chareae, family Characeae, including 15 previously described species (Chara benthamii, C. erythrogyna, C. globularis, C. karolii, C. lucida, C. porteri, C. protocharoides, C. setosa, C. submollusca, C. wightii, C. zeylanica, Lamprothamnium capitatum, L. compactum, L. stipitatum, Lychnothamnus barbatus) of which 2 are new for the Australian flora (C. erythrogyna and C. wightii), as well as 5 varieties raised to species rank (C. aridicola, C. arnhemensis, C. bancroftii, C. behriana, C. duriuscula), and 2 newly described species (C. lamprothamniformis, C. schultae). Three previously reported species in the tribe (C. braunii, C. corallina, C. fibrosa) are not recorded from the Northern Territory in this study, as previous records were based on erroneous identifications or localities. Although Northern Territory specimens of Lychnothamnus barbatus have not been seen, it has been included in this treatment, because it occurs in south-eastern Queensland, the Gulf of Carpentaria, Papua New Guinea and Timor-Leste. A key, illustrations and descriptions of all the species are provided.
Charophytes of Australia’s Northern Territory – II. Tribe Nitelleae
- Casanova, Michelle, Karol, Kenneth
- Authors: Casanova, Michelle , Karol, Kenneth
- Date: 2023
- Type: Text , Journal article
- Relation: Australian Systematic Botany Vol. 36, no. 4 (2023), p. 322-353
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- Description: This study of Northern Territory charophytes deals with the tribe Nitelleae in family Characeae. We recognise 16 species of Nitella for the Territory. The list includes seven previously described species (Nitella belangeri, N. biformis, N. congesta, N. heterophylla, N. micklei, N. myriotricha and N.tumulosa, of which N. belangeri and N. tumulosa are newly recorded for the Australian flora), and nine newly described species (N. acanthospora, N. boreali-australis, N. crocodylus, N. limosa, N.martinii, N. nitida, N. oollooensis, N. silicea and N. townsendii). Of the five previously reported Nitella species in the Northern Territory (N. hyalina, N. myriotricha, N. penicillata, N. pseudoflabellata and N. subtilissima), only N. myriotricha is recorded in this study, because the other records were based on erroneous identifications or localities. All Nitella species described here can be distinguished on the basis of their morphology and reproductive arrangement. Keys, illustrations and descriptions of all the species are provided.
- Authors: Casanova, Michelle , Karol, Kenneth
- Date: 2023
- Type: Text , Journal article
- Relation: Australian Systematic Botany Vol. 36, no. 4 (2023), p. 322-353
- Full Text:
- Reviewed:
- Description: This study of Northern Territory charophytes deals with the tribe Nitelleae in family Characeae. We recognise 16 species of Nitella for the Territory. The list includes seven previously described species (Nitella belangeri, N. biformis, N. congesta, N. heterophylla, N. micklei, N. myriotricha and N.tumulosa, of which N. belangeri and N. tumulosa are newly recorded for the Australian flora), and nine newly described species (N. acanthospora, N. boreali-australis, N. crocodylus, N. limosa, N.martinii, N. nitida, N. oollooensis, N. silicea and N. townsendii). Of the five previously reported Nitella species in the Northern Territory (N. hyalina, N. myriotricha, N. penicillata, N. pseudoflabellata and N. subtilissima), only N. myriotricha is recorded in this study, because the other records were based on erroneous identifications or localities. All Nitella species described here can be distinguished on the basis of their morphology and reproductive arrangement. Keys, illustrations and descriptions of all the species are provided.
The response of Nassella trichotoma (serrated tussock) seeds and seedlings to different levels of fire intensity
- Humphries, Talia, Florentine, Singarayer
- Authors: Humphries, Talia , Florentine, Singarayer
- Date: 2023
- Type: Text , Journal article
- Relation: Australian Journal of Botany Vol. 71, no. 4 (2023), p. 188-198
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- Description: Context Fire is an important disturbance regime in grassland communities, since it is responsible for stimulating the regeneration of many species and for maintaining levels of biodiversity. When invasive plants, such as Nassella trichotoma, establish and become widespread in a grassland community, these important fire events can be altered in intensity and frequency, which means that they are able to facilitate the establishment of the exotic species. Therefore, before fire can be recommended as a suitable control technique for invasive species, or alternatively to be integrated into grassland restoration programs, understanding the response of the seeds of exotic species to high temperatures, such as those experienced during a fire, should be well understood. Aims Our aim was to identify their response to a gradient of temperatures associated with different levels of fire intensity. We examined how increased duration of exposure affects their response, and whether seed age or seed moisture content affect the germination response of this species. Methods To gain a fuller understanding of the fire response of N. trichotoma’s seedbank, seeds were collected in 2016, 2017, 2018 and 2019 and then stored until the commencement of the experiments in 2020. Selected seeds were first subjected to an increasing temperature gradient (80°C, 100°C, 120°C, 140°C, and a control), and an increasing duration of exposure (of 1, 3, 6, and 9 min). In the second experiment, one population was selected to test these same temperatures and duration of exposure after the seeds were hydrated to 15%, 50%, or 95%. Last, seedlings were grown for 3 months under glasshouse conditions and then exposed to increasing temperatures (20°C, 60°C, 80°C, 100°C, and 120°C), and an increasing duration of exposure (3, 6, and 9 min). The seedlings were assessed 2 weeks after the heat exposure for signs of damage. Key results It was found that increased temperatures and duration of exposure had a subtle negative effect on germination parameters, including reduced total germination and increased time to 50% germination. The 140°C treatment was seen to be a significant threshold because it killed all the seeds at any duration of exposure. A significant difference among the ages of each seed lot was observed to be a factor on the tested germination metrics, with the oldest tested population (2016) demonstrating the highest germination percentage, uniformity, and rate. Seed germination percentage was significantly reduced for seeds hydrated to 95% compared with the control treatment, whereas no significant difference was observed for the seeds hydrated to 15% and 50%. For the heat treatment of the seedlings, damage to the leaves was observed in the 80°C, 100°C, and 120°C treatments, with some plants in the 120°C treatment experiencing extensive damage prior to resprouting. No seedlings were killed at the tested temperatures. Conclusions Results of this study indicated that fire may be a useful tool for reducing seedbank density by killing a high proportion of the seeds on the soil surface, or located within the top 1 cm of the soil profile, but not for seeds buried more deeply. Efficacy of fire on surface and shallow-buried seeds is improved with high seed moisture content however, these seeds buried below this depth are still protected by the soil from the lethal effects of temperature. Implications Fire implemented before seed set could be used to effectively kill a large proportion of N. trichotoma seeds. However, for more comprehensive control, it is recommended that chemical treatment is integrated with the fire treatment to improve the overall control efficiency.
- Authors: Humphries, Talia , Florentine, Singarayer
- Date: 2023
- Type: Text , Journal article
- Relation: Australian Journal of Botany Vol. 71, no. 4 (2023), p. 188-198
- Full Text:
- Reviewed:
- Description: Context Fire is an important disturbance regime in grassland communities, since it is responsible for stimulating the regeneration of many species and for maintaining levels of biodiversity. When invasive plants, such as Nassella trichotoma, establish and become widespread in a grassland community, these important fire events can be altered in intensity and frequency, which means that they are able to facilitate the establishment of the exotic species. Therefore, before fire can be recommended as a suitable control technique for invasive species, or alternatively to be integrated into grassland restoration programs, understanding the response of the seeds of exotic species to high temperatures, such as those experienced during a fire, should be well understood. Aims Our aim was to identify their response to a gradient of temperatures associated with different levels of fire intensity. We examined how increased duration of exposure affects their response, and whether seed age or seed moisture content affect the germination response of this species. Methods To gain a fuller understanding of the fire response of N. trichotoma’s seedbank, seeds were collected in 2016, 2017, 2018 and 2019 and then stored until the commencement of the experiments in 2020. Selected seeds were first subjected to an increasing temperature gradient (80°C, 100°C, 120°C, 140°C, and a control), and an increasing duration of exposure (of 1, 3, 6, and 9 min). In the second experiment, one population was selected to test these same temperatures and duration of exposure after the seeds were hydrated to 15%, 50%, or 95%. Last, seedlings were grown for 3 months under glasshouse conditions and then exposed to increasing temperatures (20°C, 60°C, 80°C, 100°C, and 120°C), and an increasing duration of exposure (3, 6, and 9 min). The seedlings were assessed 2 weeks after the heat exposure for signs of damage. Key results It was found that increased temperatures and duration of exposure had a subtle negative effect on germination parameters, including reduced total germination and increased time to 50% germination. The 140°C treatment was seen to be a significant threshold because it killed all the seeds at any duration of exposure. A significant difference among the ages of each seed lot was observed to be a factor on the tested germination metrics, with the oldest tested population (2016) demonstrating the highest germination percentage, uniformity, and rate. Seed germination percentage was significantly reduced for seeds hydrated to 95% compared with the control treatment, whereas no significant difference was observed for the seeds hydrated to 15% and 50%. For the heat treatment of the seedlings, damage to the leaves was observed in the 80°C, 100°C, and 120°C treatments, with some plants in the 120°C treatment experiencing extensive damage prior to resprouting. No seedlings were killed at the tested temperatures. Conclusions Results of this study indicated that fire may be a useful tool for reducing seedbank density by killing a high proportion of the seeds on the soil surface, or located within the top 1 cm of the soil profile, but not for seeds buried more deeply. Efficacy of fire on surface and shallow-buried seeds is improved with high seed moisture content however, these seeds buried below this depth are still protected by the soil from the lethal effects of temperature. Implications Fire implemented before seed set could be used to effectively kill a large proportion of N. trichotoma seeds. However, for more comprehensive control, it is recommended that chemical treatment is integrated with the fire treatment to improve the overall control efficiency.
Current status of and future opportunities for digital agriculture in Australia
- Hansen, Birgita, Leonard, E., Mitchell, M. C., Easton, J., Shariati, N., Mortlock, M. Y., Schaefer, M., Lamb, D. W.
- Authors: Hansen, Birgita , Leonard, E. , Mitchell, M. C. , Easton, J. , Shariati, N. , Mortlock, M. Y. , Schaefer, M. , Lamb, D. W.
- Date: 2022
- Type: Text , Journal article
- Relation: Crop and pasture science Vol. 74, no. 6 (2022), p. 524-537
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- Description: In Australia, digital agriculture is considered immature and its adoption ad hoc, despite a relatively advanced technology innovation sector. In this review, we focus on the technical, governance and social factors of digital adoption that have created a disconnect between technology development and the end user community (farmers and their advisors). Using examples that reflect both successes and barriers in Australian agriculture, we first explore the current enabling technologies and processes, and then we highlight some of the key socio-technical factors that explain why digital agriculture is immature and ad hoc. Pronounced issues include fragmentation of the innovation system (and digital tools), and a lack of enabling legislation and policy to support technology deployment. To overcome such issues and increase adoption, clear value propositions for change are necessary. These value propositions are influenced by the perceptions and aspirations of individuals, the delivery of digitally-enabled processes and the supporting legislative, policy and educational structures, better use/conversion of data generated through technology applications to knowledge for supporting decision making, and the suitability of the technology. Agronomists and early adopter farmers will play a significant role in closing the technology-end user gap, and will need support and training from technology service providers, government bodies and peer-networks. Ultimately, practice change will only be achieved through mutual understanding, ownership and trust. This will occur when farmers and their advisors are an integral part of the entire digital innovation system.
- Authors: Hansen, Birgita , Leonard, E. , Mitchell, M. C. , Easton, J. , Shariati, N. , Mortlock, M. Y. , Schaefer, M. , Lamb, D. W.
- Date: 2022
- Type: Text , Journal article
- Relation: Crop and pasture science Vol. 74, no. 6 (2022), p. 524-537
- Full Text:
- Reviewed:
- Description: In Australia, digital agriculture is considered immature and its adoption ad hoc, despite a relatively advanced technology innovation sector. In this review, we focus on the technical, governance and social factors of digital adoption that have created a disconnect between technology development and the end user community (farmers and their advisors). Using examples that reflect both successes and barriers in Australian agriculture, we first explore the current enabling technologies and processes, and then we highlight some of the key socio-technical factors that explain why digital agriculture is immature and ad hoc. Pronounced issues include fragmentation of the innovation system (and digital tools), and a lack of enabling legislation and policy to support technology deployment. To overcome such issues and increase adoption, clear value propositions for change are necessary. These value propositions are influenced by the perceptions and aspirations of individuals, the delivery of digitally-enabled processes and the supporting legislative, policy and educational structures, better use/conversion of data generated through technology applications to knowledge for supporting decision making, and the suitability of the technology. Agronomists and early adopter farmers will play a significant role in closing the technology-end user gap, and will need support and training from technology service providers, government bodies and peer-networks. Ultimately, practice change will only be achieved through mutual understanding, ownership and trust. This will occur when farmers and their advisors are an integral part of the entire digital innovation system.
A DNA toolbox for non-invasive genetic studies of sambar deer (Rusa unicolor)
- Davies, Chris, Wright, Wendy, Wedrowicz, Faye, Hogan, Fiona
- Authors: Davies, Chris , Wright, Wendy , Wedrowicz, Faye , Hogan, Fiona
- Date: 2020
- Type: Text , Journal article
- Relation: Australian Mammalogy Vol. 42, no. 1 (2020), p. 58-66
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- Description: Invasive sambar deer (Rusa unicolor) are having significant detrimental impacts on natural environments in south-eastern Australia. Little, however, is known about their ecology, limiting evidence-based management strategies directed at reducing deer impacts. Genetic data, generated from DNA isolated from deer scats, can be used to fill ecological knowledge gaps. This study outlines a non-invasive genetic sampling strategy by which good-quality DNA from a single deer scat can be used to determine (1) species of origin, (2) sex and (3) a unique DNA profile. DNA from deer tissue and sambar deer scat samples were used to develop and optimise molecular methods to collect reliable genetic information. A DNA toolbox is presented that describes how to find, collect and store scat samples, isolate DNA and use molecular markers to generate informative genetic data. Generating genetic data using this approach will support studies aimed at acquiring ecological knowledge about sambar deer. Such knowledge will be critical for developing evidence-based recommendations to improve on-ground management decisions for sambar deer.
- Authors: Davies, Chris , Wright, Wendy , Wedrowicz, Faye , Hogan, Fiona
- Date: 2020
- Type: Text , Journal article
- Relation: Australian Mammalogy Vol. 42, no. 1 (2020), p. 58-66
- Full Text:
- Reviewed:
- Description: Invasive sambar deer (Rusa unicolor) are having significant detrimental impacts on natural environments in south-eastern Australia. Little, however, is known about their ecology, limiting evidence-based management strategies directed at reducing deer impacts. Genetic data, generated from DNA isolated from deer scats, can be used to fill ecological knowledge gaps. This study outlines a non-invasive genetic sampling strategy by which good-quality DNA from a single deer scat can be used to determine (1) species of origin, (2) sex and (3) a unique DNA profile. DNA from deer tissue and sambar deer scat samples were used to develop and optimise molecular methods to collect reliable genetic information. A DNA toolbox is presented that describes how to find, collect and store scat samples, isolate DNA and use molecular markers to generate informative genetic data. Generating genetic data using this approach will support studies aimed at acquiring ecological knowledge about sambar deer. Such knowledge will be critical for developing evidence-based recommendations to improve on-ground management decisions for sambar deer.
The lay of the land : the geological evolution of the landscape
- Authors: Dahlhaus, Peter
- Date: 2019
- Type: Text , Book chapter
- Relation: Geelong's Changing Landscape : Ecology, Development and Conservation p.
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- Authors: Dahlhaus, Peter
- Date: 2019
- Type: Text , Book chapter
- Relation: Geelong's Changing Landscape : Ecology, Development and Conservation p.
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