A global review of the invasive aquatic weed Cabomba caroliniana [A. Gray] (Carolina fanwort) : current and future management challenges, and research gaps
- Authors: Roberts, Jason , Florentine, Singarayer
- Date: 2022
- Type: Text , Journal article , Review
- Relation: Weed Research Vol. 62, no. 1 (2022), p. 75-84
- Full Text: false
- Reviewed:
- Description: Cabomba caroliniana [A. Gray] (Cabombaceae), also known as Carolina fanwort, is a native of South America which has now become a serious invasive threat to aquatic systems across the world. Its capacity to inundate a water column with active fragments and seeds makes the containment and management of C. caroliniana a challenging task and an ecological and economic necessity. Previous and current management efforts have been largely focussed on biological control, drawdown methods, herbicide application, manual removal, shading and the use of a concentrated urea solution. Although these methods have shown some success in reducing large infestations, they are generally considered to be unreliable when used alone since they are unable to contain or reduce the species in the long term with a single-use treatment protocol. It is feared that, without effective, improved and integrated management strategies, C. caroliniana will continue to invade aquatic ecosystems beyond its already wide current distribution, thus causing increased global economic and environmental damage. This review will therefore explore the biology and distribution of C. caroliniana and examine the current and previous attempts for its global management. It will also evaluate the most successful current treatments and clarify where research efforts are urgently needed for the improved long-term extirpation of this aquatic invader. © 2021 European Weed Research Society
A global review of the woody invasive alien species mimosa pigra (giant sensitive plant): Its biology and management implications
- Authors: Welgama, Amali , Florentine, Singarayer , Roberts, Jason
- Date: 2022
- Type: Text , Journal article
- Relation: Plants Vol. 11, no. 18 (2022), p. 2366
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- Description: Populations of invasive alien plants create disruptive plant communities that are extremely adaptable, imposing severe ecological impacts on agriculture, biodiversity and human activities. To minimise these impacts, prevention and effective weed management strategies are urgently required, including the identification of satellite populations before they invade new areas. This is a critical element that allows weed management practices to become both successful and cost-effective. Mimosa pigra L. (Giant sensitive plant) is an invasive weed that has spread across various environments around the world and is considered one of the world’s top 100 most invasive plant species. Being adaptable to a wide range of soil types, in addition to its woody protective prickles and low palatability, M. pigra has quickly spread and established itself in a range of habitats. Current control methods of this species include biological, chemical and physical methods, together with attempts of integrated application. Reports suggest that integrated management appears to be the most effective means of controlling M. pigra since the use of any single method has not yet proved suitable. In this regard, this review synthesises and explores the available global literature and current research gaps relating to the biology, distribution, impacts and management of M. pigra. The contribution of this work will help guide land managers to design appropriate and sustainable management programs to control M. pigra.
A review of the biology, distribution patterns and management of the invasive species Amaranthus palmeri S. Watson (Palmer amaranth) : current and future management challenges
- Authors: Roberts, Jason , Florentine, Singarayer
- Date: 2022
- Type: Text , Journal article , Review
- Relation: Weed Research Vol. 62, no. 2 (2022), p. 113-122
- Full Text: false
- Reviewed:
- Description: Amaranthus palmeri S. Watson (Palmer amaranth) is an invasive agricultural weed that has quickly risen from a state of relative obscurity to now being globally regarded as one of the most economically destructive and difficult to manage weed species. It is now found in more than 45 countries where it poses a serious threat to agricultural production systems. Amaranthus palmeri is known to aggressively compete against crop plants for resources such as light, space, nutrients and soil moisture, all of which can result in significant crop yield reduction or even lead to crop failure. It has also been reported that A. palmeri is highly prone to evolve herbicide resistance; this makes management exceedingly challenging. Whilst there have been several control approaches introduced to manage the spread and impact of A. palmeri, many of them require more specific and focused research for their successful local and widespread application. In this regard, this global review explores the species’ biology and global distribution patterns, together with previous and current management strategies. It also explores and identifies promising areas of research that still require further investigation to more confidently assist in the control and containment of this globally concerning weed. © 2021 European Weed Research Society.
A unique weed problem — the control of fairy grass Lachnagrostis filiformis seedheads on Lake Learmonth in western Victoria
- Authors: Warnock, Andrew , Florentine, Singarayer , Graz, Patrick , Westbrooke, Martin
- Date: 2008
- Type: Text , Conference paper
- Relation: Paper presented at 16th Australian Weeds Conference: Weed management 2008 hot topics in the tropics, Cairns, Queensland : May 18th-22nd, 2008 p. 165-167
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- Description: The native fairy grass (Lachnagrostis filiformis (G. Forst.) Trin.) has colonised extensive areas of dry lake beds in western Victoria during the current drought. Large numbers of the plants’ detached mature panicles (seed heads) lodge against housing, fences, railway lines and other obstacles. This can be a fire hazard, degrades township aesthetics and creates a general nuisance to communities of lakeside towns. Current control measures are costly and only provide short-term solutions. A three-year study commencing in 2006 was designed to assess current and innovative control measures and develop a potential long-term management solution to the problem. Treatments applied to the bed of Lake Learmonth during the first year of the study included late-season glyphosate herbicide at two concentrations, late-season slashing, and seed broadcasting of two native species to reduce L. filiformis inflorescence biomass through competition. Slashing reduced L. filiformis inflorescence biomass and herbicide treatments successfully killed L. filiformis plants, while having no effect on germination of seed collected from sprayed plants. Although these treatments successfully limited the impact of L. filiformis on lakeside towns during the first year, the longer term efficiency is doubted. Treatment effects will be monitored over a further two years.
- Description: 2003006269
Achievements, developments and future challenges in the field of bioherbicides for weed control : a global review
- Authors: Roberts, Jason , Florentine, Singarayer , Fernando, Wannakuwattewaduge , Tennakoon, Kushan
- Date: 2022
- Type: Text , Journal article
- Relation: Plants Vol. 11, no. 17 (2022), p.
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- Description: The intrusion of weeds into fertile areas has resulted in significant global economic and environmental impacts on agricultural production systems and native ecosystems, hence without ongoing and repeated management actions, the maintenance or restoration of these systems will become increasingly challenging. The establishment of herbicide resistance in many species and unwanted pollution caused by synthetic herbicides has ushered in the need for alternative, eco-friendly sustainable management strategies, such as the use of bioherbicides. Of the array of bioherbicides currently available, the most successful products appear to be sourced from fungi (mycoherbicides), with at least 16 products being developed for commercial use globally. Over the last few decades, bioherbicides sourced from bacteria and plant extracts (such as allelochemicals and essential oils), together with viruses, have also shown marked success in controlling various weeds. Despite this encouraging trend, ongoing research is still required for these compounds to be economically viable and successful in the long term. It is apparent that more focused research is required for (i) the improvement of the commercialisation processes, including the cost-effectiveness and scale of production of these materials; (ii) the discovery of new production sources, such as bacteria, fungi, plants or viruses and (iii) the understanding of the environmental influence on the efficacy of these compounds, such as atmospheric CO2, humidity, soil water stress, temperature and UV radiation. © 2022 by the authors.
After the Goldrush: Developing closure criteria for a mined landscape
- Authors: Dorinila, Augustine , Bellette, Marc , Florentine, Singarayer
- Date: 2015
- Type: Text , Book chapter
- Relation: Responsible Mining: case studies in managing social and environmental risks in the developed world Chapter 22 p. 639-662
- Full Text: false
- Reviewed:
- Description: Chapter 22 provides an example of variations in local conditions and authorized specifications. The authors present a reclamation case study of an area that was mined 155 years during the gold rush in the state of Victoria, Australia, resulting in significant heavy metal contamination. Using the normal approach of storing the original "natural" vegetation without consideration of ecological differences was not realistic. Measurement of success should cover composition, structure, function and monitoring of invertebrates, because all of these are important components of the ecosystem. This 10 year field trial concluded that (1) only hard seeds survive the pressure of being entombed in stockpiles, so soil should be used soon after stripping to maximize recruitment and diversity; (2) appropriate criteria should be employed for mined sites, especially tailings facilities, with the objective of reverting these to sef-sustaining ecosystems; and (3) future projects should include variables, such as indices of diversity within the ecosystem attributes and at least two reference sites, to suitably portray the ecosystem variation. The authors also discuss how environmental legislation should be based on the ecological settings of the area.
- Description: Chapter 22 provides an example of variations in local conditions and authorized specifications. The authors present a reclamation case study of an area that was mined 155 years during the gold rush in the state of Victoria, Australia, resulting in significant heavy metal contamination. Using the normal approach of storing the original "natural" vegetation without consideration of ecological differences was not realistic. Measurement of success should cover composition, structure, function and monitoring of invertebrates, because all of these are improtant components of the ecosystem. This 10 year field trial concluded that (1) only hard seeds survive the pressure of being entombed in stockpiles, so soil should be used soon after stripping to maximize recruitment and diversity; (2) appropriate criteria should be employed for mined sites, especially tailings facilities, with the objective of reverting these to sef-sustaining ecosystems; and (3) future projects should include variables, such as indices of diversity within the ecosystem attributes and at least two reference sites, to suitably portray the ecosystem variation. The authors also discuss how environmental legislation should be based on the ecological settings of the area.
Age distribution of Slender Cypress-pine (Callitris gracilis) within Pine Plains, Wyperfeld National Park
- Authors: Gibson, Matthew , Florentine, Singarayer
- Date: 2008
- Type: Text , Report
- Full Text:
- Description: In semi-arid north-west Victoria, Slender Cypress-pine (Callitris gracilis) is an important tree hollow forming species for hollow dependent fauna, particularly the Major Mitchell’s Cockatoo (Lophocroa leadbeateri). Long-term management of the Major Mitchell’s Cockatoo must be based on an understanding of the age distribution of Slender Cypress-pine within important habitat areas and the age at which the trees form suitable nesting hollows. This project involved an investigation of the Slender Cypress-pine population within the Pine Plains section of Wyperfeld National Park, north-west Victoria. The objectives of the project were to determine the relationship between stem diameter and age of Slender Cypress-pine, and investigate the age distribution of the Slender Cypress-pine population within Pine Plains. Determination of the relationship between stem diameter and stem age will enable the determination of the number of years trees require to start forming hollows, and to form large hollows suitable for Major Mitchell’s Cockatoo breeding.
Agriculture and crop protection its global importance and relationship with climate change
- Authors: Jabran, Khawar , Florentine, Singarayer , Chauhan, Bhagirath
- Date: 2020
- Type: Text , Book chapter
- Relation: Crop protection under changing climate Chapter 1 p. 1-16
- Full Text: false
- Reviewed:
- Description: Agricultural practice, which includes well-established systems of cropping, pasture and forestry, represents a continual and essential dependence on healthy arable land across the globe and requires safeguarding with sustainable fertilization and pest control measures. This natural resource system must be continually protected from deliberate and inadvertent damage, in order to provide a suitable source of current and future amenities for all inhabitants of the planet. In this respect, it is morally and ethically necessary that we strive to manage the productivity and well-being of agricultural land in a way that will fulfil the necessities of the present generations and do not compromise needs of the future generations (Bruntland et al. 2012).
Allelopathic effects of Eucalyptus victrix L. on Eucalyptus species and grasses
- Authors: Florentine, Singarayer , Fox, John
- Date: 2003
- Type: Text , Journal article
- Relation: Allelopathy Journal Vol. 11, no. 1 (2003), p. 77-83
- Full Text: false
- Reviewed:
- Description: C1
- Description: 2003000583
Allelopathic potential of the newly emerging weed solanum mauritianum Scop. (solanaceae) in the wet tropics of north-east Queensland
- Authors: Florentine, Singarayer , Westbrooke, Martin
- Date: 2003
- Type: Text , Journal article
- Relation: Plant Protection Quarterly Vol. 18, no. 1 (2003), p. 23-25
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- Reviewed:
- Description: Solanum mauritianum
- Description: C1
- Description: 2003004172
Amaranthus retroflexus L (redroot pigweed) : effects of elevated CO2 and soil moisture on growth and biomass and the effect of radiant heat on seed germination
- Authors: Weller, Sandra , Florentine, Singarayer , Welgama, Amali , Chadha, Aakansha , Turville, Christopher
- Date: 2021
- Type: Text , Journal article
- Relation: Agronomy Vol. 11, no. 4 (2021), p.
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- Description: Amaranthus retroflexus L. (Amaranthaceae), Redroot pigweed, is native to North America, but has become a weed of agriculture worldwide. Previous research into competition with food crops found it significantly reduces yields. Additionally, taxonomy, biomass allocation, physiological responses to light intensity, water stress, elevated CO2, and herbicide resistance have been inves-tigated. To extend other research findings, we investigated growth and biomass yield in response to (i) soil moisture stress, and (ii) drought and elevated CO2. Additionally, we investigated seed germination rates following exposure to three elevated temperatures for two different time periods. Overall, moisture stress reduced plant height, stem diameter, and number of leaves. Elevated CO2 (700 ppm) appeared to reduce negative impacts of drought on biomass productivity. Heating seeds at 120◦C and above for either 180 or 300 s significantly reduced germination rate. These results inform an understanding of potential responses of A. retroflexus to future climate change and will be used to predict future occurrence of this weed. The finding that exposing seeds to high temperatures retards germination suggests fire could be used to prevent seed germination from soil seed banks, particularly in no-till situations, and therefore may be used to address infestations or prevent further spread of this weed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliates “Sandra Weller, Singarayer Florentine, Amali Welgama, Aakansha Chadha, Chrisopher Turville" are provided in this record**
An assessment of riparian restoration outcomes in two rural catchments in south-western Victoria : Focusing on tree and shrub species richness, structure and recruitment characteristics
- Authors: Wevill, Tricia , Florentine, Singarayer
- Date: 2014
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 15, no. 2 (2014), p. 133-139
- Full Text: false
- Reviewed:
- Description: Riparian ecosystems are among the most degraded systems in the landscape, and there has been substantial investment in their restoration. Consequently, monitoring restoration interventions offers opportunities to further develop the science of riparian restoration, particularly how to move from small-scale implementation to a broader landscape scale. Here, we report on a broad range of riparian revegetation projects in two regions of south-western Victoria, the Corangamite and Glenelg-Hopkins Catchment Management Areas. The objectives of restoration interventions in these regions have been stated quite broadly, for example, to reinstate terrestrial habitat and biodiversity, control erosion and improve water quality. This study reports on tree and shrub composition, structure and recruitment after restoration works compared with remnant vegetation found regionally. Within each catchment, a total of 57 sites from six subcatchments were identified, representing three age-classes: <4, 4-8 and >8-12 years after treatment, as well as untreated (control) sites. Treatments comprised fencing to exclude stock, spraying or slashing to reduce weed cover, followed by planting with tube stock. Across the six subcatchments, 12 reference (remnant) sites were used to provide a benchmark for species richness, structural and recruitment characteristics and to aid interpretation of the effects of the restoration intervention. Vegetation structure was well developed in the treated sites by 4-8 years after treatment. However, structural complexity was higher at remnant sites than at treated or untreated sites due to a higher richness of small shrubs. Tree and shrub recruitment occurred in all remnant sites and at 64% of sites treated >4 years ago. Most seedling recruitment at treatment sites was by Acacia spp. This assessment provides data on species richness, structure and recruitment characteristics following restoration interventions. Data from this study will contribute to longitudinal studies of vegetation processes in riparian landscapes of south-western Victoria. © 2014 Ecological Society of Australia and Wiley Publishing Asia Pty Ltd.
An integrated approach for the restoration of Australian temperate grasslands invaded by Nassella trichotoma
- Authors: Humphries, Talia , Turville, Christopher , Sinclair, Steven , Florentine, Singarayer
- Date: 2022
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 12, no. 1 (2022), p.
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- Description: Invasive plants are considered to be one of the biggest threats to environmental assets, and once established, they can be immensely difficult to control. Nassella trichotoma is an aggressive, perennial grass species, and is considered to be one of the most economically damaging weeds to grazing systems due to its unpalatability, as well as being one of the leading causes of biodiversity loss in grassland communities. This species produces high density seedbanks that rapidly respond to disturbance events. Despite control programs being developing in Australia since the 1930s, this species is still widespread throughout south-east Australia, indicating that a new management approach is critical to control this Weed of National Significance at the landscape scale. The present study explored the effect of 12 different combinations of herbicide, fire, a second application of herbicide, grazing exclusion, tillage and broadcasting seeds in order to reduce the above and below-ground density of N. trichotoma. A control treatment was also included. The results were assessed using a Hierarchy analysis, whereby treatments of increasing complexity were compared for their efficacy in reducing N. trichotoma cover and seedbank density, while simultaneously increasing the establishment of the broadcast species. Whilst all integrated treatments effectively reduced N. trichotoma’s seedbank, the treatments that included fire performed significantly better at simultaneously reducing N. trichotoma and increasing the establishment of broadcasted seeds. Overall, the integration of herbicide, fire and broadcasting native seeds was observed to provide the most economically feasible management strategy for the landscape scale restoration of a degraded temperate grassland dominated by N. trichotoma. © 2022, The Author(s).
An investigation of the effects of stage of ensilage on Nassella neesiana seeds, for reducing seed viability and injury to livestock
- Authors: Weller, Sandra , Florentine, Singarayer , Sillitoe, Jim , Grech, Charles , McLaren, David
- Date: 2016
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 6, no. (2016), p. 1-7
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- Description: The noxious weed Nassella neesiana is established on a wide range of productive land throughout southeastern Australia. N. neesiana seeds, when mature, are sharp, causing injury to livestock, thus posing a problem in fodder bales. To reduce infestations of agricultural weeds in situ, production of silage from weed-infested pastures is practised as part of integrated weed management (IWM). However, there is little data to demonstrate whether this process is useful to reduce infestations or the harmful properties of N. neesiana. Therefore, the minimum duration of ensilage required to reduce the viability of N. neesiana seeds was investigated, both with and without addition of ensilage inoculants in this process. Also, the decreasing propensity of the seeds to injure livestock, after various times and conditions of ensilage, was assessed. Ensilage inoculant reduced seed germination probability to zero after 35 days. When no inoculant was added, zero viability was achieved after 42 days. A qualitative assessment of the hardness of ensilaged seeds found seed husks were softer (and therefore safer) after 42 days, whether inoculant was used or not. Therefore, we suggest that both the viability of N. neesiana seeds and hardness of seed casings are significantly reduced after 42 days, thereby reducing the risks of seed dispersal and injury to livestock.
An investigation of the soil seedbank and seed germination of perennial species in Belah (Casuarina pauper)woodlands in north-west Victoria
- Authors: Callister, Kate , Florentine, Singarayer , Westbrooke, Martin
- Date: 2018
- Type: Text , Journal article
- Relation: Australian Journal of Botany Vol. 66, no. 3 (2018), p. 202-212
- Full Text: false
- Reviewed:
- Description: Semiarid and arid woodlands across much of southern Australia have been subject to prolonged high total grazing pressure leading to loss of species diversity and a lack of recruitment of long-lived perennial species. Regeneration of perennial species requires grazing pressure to be maintained at low levels, but gaps remain in our ecological understanding of regeneration potential. The present study investigated the abundance of germinable seed in the soil seedbank in high quality remnants of Casuarina pauper F.Muell. ex L.A.S.Johnson (Belah) woodlands in north-west Victoria. Seed viability and response to six seed pretreatments including dry heat, wet heat, smoky water, soaking in distilled water, cold stratification and sand scarification were also tested to determine whether seed factors may be limiting regeneration. Results suggest that seed viability was not a limiting regeneration factor for nine out of the 10 perennial species tested with the exception of Alectryon oleifolius S.T. Reynolds. Only small amounts of seed from perennial species, largely Chenopodiaceae species and C. pauper, were found in the soil seedbanks of intact sites, suggesting component perennial species do not maintain long-term soil seedbanks. Results suggest that natural recovery of perennial species diversity in depauperate sites will depend on seed dispersal.
Annual ryegrass (Lolium rigidum Gaud) competition altered wheat grain quality : A study under elevated atmospheric CO2 levels and drought conditions
- Authors: Fernando, Nimesha , Florentine, Singarayer , Naiker, Mani , Panozzo, Joe , Chauhan, Bhagirath
- Date: 2019
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 276, no. (2019), p. 285-290
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- Description: Annual ryegrass is one of the most serious, costly weeds of winter cropping systems in Australia. To determine whether its competition-mediated plant defence mechanisms effect on wheat grain quality, wheat (cv. Yitpi) and annual ryegrass were grown under two levels of CO2 (400 ppm; (a[CO2]) vs 700 ppm; (e[CO2]), two levels of water (well-watered vs drought) and two types of competition (wheat only; (W), and wheatxannual ryegrass; (W x R) with four replicates. The competitionx[CO2] interaction had a significant effect on wheat grain protein content, where it was increased in W x R under both e[CO2] (+ 17%) and a[CO2] (+ 21%). Grain yield, total grain reducing power and phenolic content were significantly affected by [CO2] x drought x competition. In a summary, annual ryegrass competition significantly altered the wheat grain quality under both [CO2] levels (depending on the soil water level), while also decreasing the grain yield.
Arid land invasive weed Salvia verbenaca L. (wild sage) : Investigation into seedling emergence, soil seedbank, allelopathic effects, and germination
- Authors: Fisher, R. , Florentine, Singarayer , Westbrooke, Martin
- Date: 2016
- Type: Text , Conference paper
- Relation: Twentieth Australian Weeds Conference
- Full Text: false
- Reviewed:
- Description: y Salvia verbenaca L., wild sage (Lamiaceae) is native to western and southern Europe. In Australia S. verbenaca is considered an environmental weed with high invasiveness often growing on disturbed sites: tracks, roadsides and around earth tanks. Little is known about the ecology of this invasive species in Australia. Therefore, our objectives in this study were to determine: (i) seedling emergence in relation to sowing depth, (ii) density ofsoilseed bank, (iii) allelopathic effects, (iv) favourable conditions for seed germination of three month old and nine years old seeds, and (v) seed longevity. Of four burial depths, only surface sown seeds germinated and survived. From the soil seedbank, S. verbenaca density was 343 ± 198 m−2. For the allelopathic effects of S. verbenaca, neither the extract nor the leachate inhibited germination of L. sativa; however, the growth of the radicle of seedlings was shown to decrease. Germination was highest at 20°C under 12 h light/12 h dark. Burial of seeds in the field prior to germination reduced viability over time. Germination of three month old seed wassignificantly less than nine year old seed. In conclusion, it is clear that S. verbenaca functions as a casual weed in arid and semi-arid environments of Australia. Understanding the plants’ ecological characteristics in this study will help us take appropriate control measures for this species.
Arid land vegetation dynamics after a rare flooding event : influence of fire and grazing
- Authors: Westbrooke, Martin , Florentine, Singarayer , Milberg, Per
- Date: 2005
- Type: Text , Journal article
- Relation: Journal of Arid Environments Vol. 61, no. 2 (Apr 2005), p. 249-260
- Full Text:
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- Description: Arid vegetation is subjected to more or less frequent fire, drought, and sporadic flooding events and grazing. Whilst fire, drought and grazing have been the subject of considerable research, little is known of the impact of flooding in arid environments. In this study we examined opportunistically the effects of a flooding event, and its interaction with fire and grazing on moulding arid vegetation in New South Wales, Australia. We assessed vegetation approximately 2 and 5 years after recession of the water in fenced and unfenced plots subjected to different combinations of flooding and fire. Number of species per area dropped from 11.8 to 5.7 per 625 m(2). Vegetation in plots left open to grazing by vertebrates differed from fenced plots, but the amount of variation explained was small compared with flooding and the change over time. The taxa mostly associated with flooding were Eragrostis spp., Pseudognaphalium luteoalbum and the exotic Nicotiana glauca. Major flooding events not only trigger native species' germination and recruitment but may also create an avenue for exotic species to invade. (C) 2004 Elsevier Ltd. All rights reserved.
- Description: C1
- Description: 2003001050
Assessing seed longevity of the Invasive Weed Navua Sedge (Cyperus aromaticus), by artificial ageing
- Authors: Chadha, Aakansha , Florentine, Singarayer , Dhileepan, Kunjithapatham , Turville, Christopher
- Date: 2022
- Type: Text , Journal article
- Relation: Plants Vol. 11, no. 24 (2022), p.
- Full Text:
- Reviewed:
- Description: Navua sedge (Cyperus aromaticus (Ridley) Mattf. & Kukenth) is a significant agricultural and environmental weed found in tropical island countries including north Queensland, Australia. It is a prolific seed producer and consequently forms a high-density seedbank, and therefore understanding the longevity and persistence of the seeds can provide critical information required for the management of this species. A laboratory-controlled artificial ageing experiment was conducted where the seeds were exposed to a temperature of 45 °C and 60% relative humidity for 125 days. Seeds were removed at various times (1, 2, 5, 9, 20, 30, 50, 75, 100 and 125 days) and their viability determined through standard germination tests. It took 20 days in the artificial ageing environment for the seeds to decline to 50% viability which indicates that Navua sedge has relatively short-lived persistent seeds. These findings will assist in developing a better understanding of the seedbank dynamics of this invasive species, allowing managers to tactically implement control strategies and prepare budgets for ongoing treatments, and have implications for the duration and success of management programs. © 2022 by the authors.
Assessing seedbank longevity and seed persistence of the invasive tussock grass nassella trichotoma using in-field burial and laboratory-controlled ageing
- Authors: Humphries, Talia , Florentine, Singarayer
- Date: 2022
- Type: Text , Journal article
- Relation: Plants Vol. 11, no. 18 (2022), p.
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- Description: The ability to produce highly dense and persistent seedbanks is a major contributor to the successful widespread establishment of invasive plants. This study seeks to identify seed persistence and seedbank longevity for the invasive tussock grass Nassella trichotoma (Nees.) Hack. ex Arechav in order to recommend management strategies for preventing re-emergence from the seedbank. To determine the seedbank longevity and persistence, two experiments were conducted: (i) seeds were buried at four depths (0, 1, 2, and 4 cm) and collected and assessed for viability, seed decay, and in-field germination after 6, 9, 12, 15, and 18 months of field burial; and (ii) seeds were exposed to artificial ageing conditions (60% RH and 45 °C) for 1, 2, 5, 9, 20, 30, 50, 75, 100, and 120 days, and viability was determined through germination tests and tetrazolium tests. Less than 10% of the seeds collected after 12 months of in-field burial were viable. The artificial ageing treatment found germination declined to 50% after 5.8 days, further suggesting that N. trichotoma seeds are short lived. The results from both experiments indicate that N. trichotoma has a transient seedbank, with less than 10% of the seeds demonstrating short-term persistence. It is likely the persistent seeds beyond 12 months were exhibiting secondary dormancy as viable seeds did not germinate under optimal germination conditions. The “Best Practice Guidelines” recommend monitoring for seedbank recruitment for at least three years after treating N. trichotoma infestations. The results of this study support this recommendation as a small proportion of the seeds demonstrated short-term persistence. © 2022 by the authors.