- Florentine, Singarayer, Westbrooke, Martin, Milberg, Per, Gibson, Matthew
- Authors: Florentine, Singarayer , Westbrooke, Martin , Milberg, Per , Gibson, Matthew
- Date: 2008
- Type: Text , Journal article
- Relation: Australian Forestry Vol. 71, no. 1 (2008), p. 48-53
- Full Text:
- Reviewed:
- Description: During June 1998, a severe windstorm caused significant damage to a sub-alpine stand of Eucalyptus delegatensis (Myrtaceae) at the Snowy River National Park. In 2002, about 4.5 y after the windstorm, a study documented the effects on E. delegatensis and early understorey succession. In February 2003, wildfire burnt across the windthrow site and we examined the seedling recruitment patterns at windthrow–burn and burn-only sites. Our aim was to document the regeneration of the canopy-dominant E. delegatensis and to confirm that Acacia dealbata is a pioneer species that potentially interferes with or prevents regeneration of E. delegatensis. Permanent transects were established within the windthrow–burn and burn-only sites. The data suggest that the heavily disturbed (mounded) soil at the windthrow site had a strong positive influence on regeneration of both species. By providing favourable growing conditions, the disturbed soil appears to have assisted seedling survival and subsequent growth of the E. delegatensis, despite competition from dense, concurrently established A. dealbata.
- Description: C1
Characterising and improving the deteriorating trends in soil physical quality under banana
- Rasiah, Velu, Armour, John, Moody, P., Pattison, A., Lindsay, S., Florentine, Singarayer
- Authors: Rasiah, Velu , Armour, John , Moody, P. , Pattison, A. , Lindsay, S. , Florentine, Singarayer
- Date: 2009
- Type: Text , Journal article
- Relation: Australian Journal of Soil Research Vol. 47, no. 6 (2009), p. 574-584
- Full Text:
- Reviewed:
- Description: Deterioration in soil physical quality under intensive tillage practices is a norm rather than an exception. The objectives of this study were to (i) evaluate total porosity (TP) as an indicator parameter to assess the impact of banana cropping on compaction and infiltration in soils, and (ii) assess the effectiveness of different interrow grass-covers in minimising the deteriorating trends. Depth-incremented TP under banana rows and interrows from 4 sites, corresponding forest sites, and from 3 interrow grass-cover treatments were computed from bulk density measurements. The TP results show the compacted depth ranged from 0.35 to 0.45m in banana rows and from 0.35 to 1.0m in the interrows. The TP in 0.10m depth increments decreased in the order: forest > rows > interrows, and was positively correlated with soil organic C (OC) and negatively with wheel traffic stress (WTS). The multiple regression analysis showed that 77% of the variability in TP was accounted for by clay + silt, OC, and WTS. We show that a threshold compaction index (DIt) of 0.81-0.83 can be estimated from TP regardless of the soil type. Depending on the soil type and the cultural practices followed, infiltration decreased from 0.75 mm/s in rainforest to 0.23 mm/s under banana in 1 soil type compared with 2.55 mm/s in forest and 0.85 mm/s under banana in another. After 18 months of interrow grass-covers we found the deterioration in TP was minimum under the indigenous grass-cover but not under the 2 improved species. We conclude the interrow grass-covers were effective in minimising WTS associated compaction and reduction in infiltration.
- Authors: Rasiah, Velu , Armour, John , Moody, P. , Pattison, A. , Lindsay, S. , Florentine, Singarayer
- Date: 2009
- Type: Text , Journal article
- Relation: Australian Journal of Soil Research Vol. 47, no. 6 (2009), p. 574-584
- Full Text:
- Reviewed:
- Description: Deterioration in soil physical quality under intensive tillage practices is a norm rather than an exception. The objectives of this study were to (i) evaluate total porosity (TP) as an indicator parameter to assess the impact of banana cropping on compaction and infiltration in soils, and (ii) assess the effectiveness of different interrow grass-covers in minimising the deteriorating trends. Depth-incremented TP under banana rows and interrows from 4 sites, corresponding forest sites, and from 3 interrow grass-cover treatments were computed from bulk density measurements. The TP results show the compacted depth ranged from 0.35 to 0.45m in banana rows and from 0.35 to 1.0m in the interrows. The TP in 0.10m depth increments decreased in the order: forest > rows > interrows, and was positively correlated with soil organic C (OC) and negatively with wheel traffic stress (WTS). The multiple regression analysis showed that 77% of the variability in TP was accounted for by clay + silt, OC, and WTS. We show that a threshold compaction index (DIt) of 0.81-0.83 can be estimated from TP regardless of the soil type. Depending on the soil type and the cultural practices followed, infiltration decreased from 0.75 mm/s in rainforest to 0.23 mm/s under banana in 1 soil type compared with 2.55 mm/s in forest and 0.85 mm/s under banana in another. After 18 months of interrow grass-covers we found the deterioration in TP was minimum under the indigenous grass-cover but not under the 2 improved species. We conclude the interrow grass-covers were effective in minimising WTS associated compaction and reduction in infiltration.
Controlling wind blown Lachnagrostis filiformis (fairy grass) seed heads in western Victoria
- Warnock, Andrew, Florentine, Singarayer, Graz, Patrick, Westbrooke, Martin
- Authors: Warnock, Andrew , Florentine, Singarayer , Graz, Patrick , Westbrooke, Martin
- Date: 2009
- Type: Text , Conference paper
- Relation: Paper presented at Fourth Victorian Weed Conference : Plants behaving badly - in agriculture and the environment, Mercure Hotel, Geelong, Victoria : 7th-8th October 2009
- Full Text:
- Description: 2003007372
- Authors: Warnock, Andrew , Florentine, Singarayer , Graz, Patrick , Westbrooke, Martin
- Date: 2009
- Type: Text , Conference paper
- Relation: Paper presented at Fourth Victorian Weed Conference : Plants behaving badly - in agriculture and the environment, Mercure Hotel, Geelong, Victoria : 7th-8th October 2009
- Full Text:
- Description: 2003007372
Nitrate import-export dynamics in groundwater interacting with surface-water in a wet-tropical environment
- Rasiah, Velu, Armour, John, Cogle, A.L., Florentine, Singarayer
- Authors: Rasiah, Velu , Armour, John , Cogle, A.L. , Florentine, Singarayer
- Date: 2010
- Type: Text , Journal article
- Relation: Australian Journal of Soil Research Vol. 48, no. 4 (2010), p. 361-370
- Full Text:
- Reviewed:
- Description: Solute import-export dynamics in groundwater (GW) systems interacting with surface-water are complex, particularly under farming systems receiving high fertiliser/pesticide inputs in high rainfall regions. We investigated whether any linkage existed between nitrate-N in: (i) leachate (LC) collected at similar to 1m depth under banana (Musa) and that in GW, and (ii) GW and drain-water (DW). We also assessed the hazard/risk of the concentrations against the trigger values proposed for the sustainable health of different aquatic ecosystems. The LC, GW, and DW samples were collected at short intervals during 3 consecutive rainy seasons (January-July) from a similar to 300-ha banana farm in the wet tropical Tully River Catchment in north-east Queensland, Australia. Water samples were analysed for nitrate-N, dissolved organic carbon, and electrical conductivity. The coefficients of variation, ranging from 13 to 132%, obtained for solute concentrations in LC, GW, and DW indicated large within-and between-season temporal variations. The mean nitrate-N concentrations in LC, GW, and DW were 5320, 4135, and 1976 mu g/L, respectively, and were orders of magnitude higher than the trigger values proposed for the sustainable health of most of the neighbouring aquatic ecosystems. Significant positive associations, with correlation coefficients ranging from 0.56 to 0.96, existed between rainfall received and LC volume collected, and between LC volume and solute concentration, including nitrate-N, in the LC. Similar associations existed between the solutes in (i) LC and GW and (ii) GW and DW. From these associations we conclude the unused/under-utilised nitrate that leached below the root-zone was imported into the GW by the percolating rainwater and was exported into the drain via GW base-flow discharge.
- Description: 2003008225
- Authors: Rasiah, Velu , Armour, John , Cogle, A.L. , Florentine, Singarayer
- Date: 2010
- Type: Text , Journal article
- Relation: Australian Journal of Soil Research Vol. 48, no. 4 (2010), p. 361-370
- Full Text:
- Reviewed:
- Description: Solute import-export dynamics in groundwater (GW) systems interacting with surface-water are complex, particularly under farming systems receiving high fertiliser/pesticide inputs in high rainfall regions. We investigated whether any linkage existed between nitrate-N in: (i) leachate (LC) collected at similar to 1m depth under banana (Musa) and that in GW, and (ii) GW and drain-water (DW). We also assessed the hazard/risk of the concentrations against the trigger values proposed for the sustainable health of different aquatic ecosystems. The LC, GW, and DW samples were collected at short intervals during 3 consecutive rainy seasons (January-July) from a similar to 300-ha banana farm in the wet tropical Tully River Catchment in north-east Queensland, Australia. Water samples were analysed for nitrate-N, dissolved organic carbon, and electrical conductivity. The coefficients of variation, ranging from 13 to 132%, obtained for solute concentrations in LC, GW, and DW indicated large within-and between-season temporal variations. The mean nitrate-N concentrations in LC, GW, and DW were 5320, 4135, and 1976 mu g/L, respectively, and were orders of magnitude higher than the trigger values proposed for the sustainable health of most of the neighbouring aquatic ecosystems. Significant positive associations, with correlation coefficients ranging from 0.56 to 0.96, existed between rainfall received and LC volume collected, and between LC volume and solute concentration, including nitrate-N, in the LC. Similar associations existed between the solutes in (i) LC and GW and (ii) GW and DW. From these associations we conclude the unused/under-utilised nitrate that leached below the root-zone was imported into the GW by the percolating rainwater and was exported into the drain via GW base-flow discharge.
- Description: 2003008225
Effects of Tetranychus lintearius (Acari : Tetranychidae) on the structure and water potential in the foliage of the invasive Ulex europaeus (Fabaceae) in Australia
- Marriott, Jeremy, Florentine, Singarayer, Raman, Anantanarayanan
- Authors: Marriott, Jeremy , Florentine, Singarayer , Raman, Anantanarayanan
- Date: 2013
- Type: Text , Journal article
- Relation: International Journal of Acarology Vol. 39, no. 4 (2013), p. 275-284
- Full Text:
- Reviewed:
- Description: Ulex europaeus, a native of Western Europe and the Mediterranean coast, is a serious agricultural and environmental weed in many parts of the earth, including Australia. Tetranychus lintearius attacks U. europaeus in its natural range and is one of the four biological control agents introduced into Australia to regulate populations of U. europaeus. Tetranychus lintearius is specific to different species of Ulex, which enhances its status as a key biological control agent. Little is known on the physiological effects and structural changes induced by T. lintearius on U. europaeus. This article describes anatomical changes and evaluates the physiological effects in U. europaeus consequent to feeding by T. lintearius for more than 100 d. This study demonstrates that feeding by T. lintearius reduces the quantity of photosynthetic tissue in U. europaeus, as a result of feeding on mesophyll parenchyma by inserting its stylets through the stomatal aperture. Unfed parenchyma cells display signs of stress, either exhibiting deformed cell organelles aligned along the walls of vacant cells or with cells with no well-defined cell organelles. Subsequent to T. lintearius feeding, leaves externally manifest bleaching. After feeding by a population of T. lintearius, leaf water potential is decreased by 30% and tender shoots lose their turgor, indicating water-related stress. Tetranychus lintearius has the potential to decelerate vigour and retard the competitiveness of U. europaeus by inflicting stress. Our findings reinforce the use of T. lintearius in the biological management of populations of U. europaeus in temperate Australia.
- Authors: Marriott, Jeremy , Florentine, Singarayer , Raman, Anantanarayanan
- Date: 2013
- Type: Text , Journal article
- Relation: International Journal of Acarology Vol. 39, no. 4 (2013), p. 275-284
- Full Text:
- Reviewed:
- Description: Ulex europaeus, a native of Western Europe and the Mediterranean coast, is a serious agricultural and environmental weed in many parts of the earth, including Australia. Tetranychus lintearius attacks U. europaeus in its natural range and is one of the four biological control agents introduced into Australia to regulate populations of U. europaeus. Tetranychus lintearius is specific to different species of Ulex, which enhances its status as a key biological control agent. Little is known on the physiological effects and structural changes induced by T. lintearius on U. europaeus. This article describes anatomical changes and evaluates the physiological effects in U. europaeus consequent to feeding by T. lintearius for more than 100 d. This study demonstrates that feeding by T. lintearius reduces the quantity of photosynthetic tissue in U. europaeus, as a result of feeding on mesophyll parenchyma by inserting its stylets through the stomatal aperture. Unfed parenchyma cells display signs of stress, either exhibiting deformed cell organelles aligned along the walls of vacant cells or with cells with no well-defined cell organelles. Subsequent to T. lintearius feeding, leaves externally manifest bleaching. After feeding by a population of T. lintearius, leaf water potential is decreased by 30% and tender shoots lose their turgor, indicating water-related stress. Tetranychus lintearius has the potential to decelerate vigour and retard the competitiveness of U. europaeus by inflicting stress. Our findings reinforce the use of T. lintearius in the biological management of populations of U. europaeus in temperate Australia.
Plant recruitment and survival as indicators of ecological success in abandoned pasture land in Nurcoung
- Florentine, Singarayer, Gardner, Jessica, Graz, Patrick, Moloney, Sean
- Authors: Florentine, Singarayer , Gardner, Jessica , Graz, Patrick , Moloney, Sean
- Date: 2013
- Type: Text , Journal article
- Relation: Ecological Processes Vol. 2, no. 1-3 (2013), p.
- Full Text:
- Reviewed:
- Description: One of the major impediments to developing better restoration strategies is the inadequate documentation of past restoration efforts. In 2008, Greening Australia commenced ecological restoration on the Nurcoung property in Victoria to enhance local biodiversity, and in this paper we report on the habitat restoration outcomes in the three Ecological Vegetation Classes (EVC) found on this property.
- Authors: Florentine, Singarayer , Gardner, Jessica , Graz, Patrick , Moloney, Sean
- Date: 2013
- Type: Text , Journal article
- Relation: Ecological Processes Vol. 2, no. 1-3 (2013), p.
- Full Text:
- Reviewed:
- Description: One of the major impediments to developing better restoration strategies is the inadequate documentation of past restoration efforts. In 2008, Greening Australia commenced ecological restoration on the Nurcoung property in Victoria to enhance local biodiversity, and in this paper we report on the habitat restoration outcomes in the three Ecological Vegetation Classes (EVC) found on this property.
Recruitment and functionality traits as biondicators of ecological restoration success in the Lurg Hills district, Victoria, Australia
- Monie, Kristin, Florentine, Singarayer, Palmer, Grant
- Authors: Monie, Kristin , Florentine, Singarayer , Palmer, Grant
- Date: 2013
- Type: Text , Journal article
- Relation: Ecological Processes Vol. 2, no. 27 (2013), p. 1-11
- Full Text:
- Reviewed:
- Description: Introduction The Regent Honeyeater Project commenced ecological restoration in the Lurg district in 1994, with an aim to restore habitats for the critically endangered Regent Honeyeater Anthochaera phrygia and a range of other threatened and declining species. Within this context, our study aimed to explore whether plant reproduction can be an effective measure of ecological restoration success. Methods Evaluation involved comparing attributes at unrestored, restored and remnant sites to establish whether sites displayed evidence of a clear restoration trajectory. Five age classes (unrestored, 4–6 years old, 8–10 years old, 12–14 years old and remnant areas) and two landforms (upper hills and lower hills) were considered. The diversity of woody plant species—which have easily recognisable reproductive material and which all recruit seedlings—provides easily measured parameters that have the potential to allow the determination of early establishment success and long-term ecological development of restored ecosystems. Results Restoration plantings developed in a hybrid state towards a benchmark in the lower hills; seedling species composition differed significantly among age classes, increasing in similarity with time since restoration, with some divergence from the target pathway. Composition of functional groups with reproductive outputs was also significantly different among age classes; however, a restoration trajectory was only evident in the upper hills where sites converged towards the target goal. Conclusions Divergence or deviation from the restoration trajectory was not deemed to be a restoration failure, as the variety of functional groups with fruits and diversity of seedlings recruiting indicated a potential increase in resilience in the future due to greater variability across the landscape. Plant recruitment was effective in detecting development trends towards a restoration target in this study and therefore may be a useful measure that contributes to determining ecological restoration success
- Authors: Monie, Kristin , Florentine, Singarayer , Palmer, Grant
- Date: 2013
- Type: Text , Journal article
- Relation: Ecological Processes Vol. 2, no. 27 (2013), p. 1-11
- Full Text:
- Reviewed:
- Description: Introduction The Regent Honeyeater Project commenced ecological restoration in the Lurg district in 1994, with an aim to restore habitats for the critically endangered Regent Honeyeater Anthochaera phrygia and a range of other threatened and declining species. Within this context, our study aimed to explore whether plant reproduction can be an effective measure of ecological restoration success. Methods Evaluation involved comparing attributes at unrestored, restored and remnant sites to establish whether sites displayed evidence of a clear restoration trajectory. Five age classes (unrestored, 4–6 years old, 8–10 years old, 12–14 years old and remnant areas) and two landforms (upper hills and lower hills) were considered. The diversity of woody plant species—which have easily recognisable reproductive material and which all recruit seedlings—provides easily measured parameters that have the potential to allow the determination of early establishment success and long-term ecological development of restored ecosystems. Results Restoration plantings developed in a hybrid state towards a benchmark in the lower hills; seedling species composition differed significantly among age classes, increasing in similarity with time since restoration, with some divergence from the target pathway. Composition of functional groups with reproductive outputs was also significantly different among age classes; however, a restoration trajectory was only evident in the upper hills where sites converged towards the target goal. Conclusions Divergence or deviation from the restoration trajectory was not deemed to be a restoration failure, as the variety of functional groups with fruits and diversity of seedlings recruiting indicated a potential increase in resilience in the future due to greater variability across the landscape. Plant recruitment was effective in detecting development trends towards a restoration target in this study and therefore may be a useful measure that contributes to determining ecological restoration success
Collembola (Springtails)
- Greenslade, Penelope, Florentine, Singarayer
- Authors: Greenslade, Penelope , Florentine, Singarayer
- Date: 2014
- Type: Text , Book chapter
- Relation: The distributions of invertebrate species along the Warra/Mt Weld altitudinal transect 2001/2002 and identification of taxa restricted by altitude (part of the Nature Conservation Report Series 13/4) Chapter 6 p.1-73
- Full Text:
- Reviewed:
- Description: Summary 1. The distributions of Collembola on the Warra-Mount Weld Altitudinal Transect were investigated based on samples taken from February–April 2001, November–December 2001 and January– February 2002. 2. The Collembola of the Warra-Mount Weld Altitudinal Transect was species rich with more than 40 species collected; the majority of species recorded have not been described. 3. Most of the species collected are considered endemic to Tasmania and some endemic genera were present. 4. The Malaise traps performed well indicating that a suite of species are arboreal and highly vagile. 5. No exotic (introduced, alien) species were detected in this study indicating that the area sampled has been little disturbed and is of high conservation value. 6. Altitudinal trends were evident with a small number of species only occurring at the high altitudes and others only at low altitudes. Only a few species appeared to occur at all altitudes sampled. 7. Ordination plots showed that Collembola assemblages at lower altitude sites on the Warra transect were more similar to each other than those at the higher altitude sites on Mount Weld which formed three clusters: 1100; 1200 and 1300 m; and 800, 900 and 1000 m. 8. Mount Weld sites 600 and 700 m faunas were most similar to Warra sites so forming a continuum in altitudinal zonation between Warra and Mount Weld. 9. PERMANOVA analysis of monthly pitfall catches in 2001 and 2002 showed differences between months and altitudes on both transects and that the differences between months were more distinct at the lower altitude Warra sites than on the higher altitude Mount Weld sites. This difference was particularly marked for the month of February, which was the only month surveyed in both years. 10.Much of the change in faunal assemblages along the Warra and Mount Weld altitudinal transect seemed to be the result of changes in vegetation cover. The most abrupt faunal transitions took place across the tree line between 1000 and 1100 m and a smaller change from lowland forest to subalpine woodland on the Mount Weld transect. 11.Much material in the pitfalls was in very poor condition because of the long trapping time with unsuitable preservative so could not be identified to species but rough estimates were made of numbers of individuals in each family or genus.
- Authors: Greenslade, Penelope , Florentine, Singarayer
- Date: 2014
- Type: Text , Book chapter
- Relation: The distributions of invertebrate species along the Warra/Mt Weld altitudinal transect 2001/2002 and identification of taxa restricted by altitude (part of the Nature Conservation Report Series 13/4) Chapter 6 p.1-73
- Full Text:
- Reviewed:
- Description: Summary 1. The distributions of Collembola on the Warra-Mount Weld Altitudinal Transect were investigated based on samples taken from February–April 2001, November–December 2001 and January– February 2002. 2. The Collembola of the Warra-Mount Weld Altitudinal Transect was species rich with more than 40 species collected; the majority of species recorded have not been described. 3. Most of the species collected are considered endemic to Tasmania and some endemic genera were present. 4. The Malaise traps performed well indicating that a suite of species are arboreal and highly vagile. 5. No exotic (introduced, alien) species were detected in this study indicating that the area sampled has been little disturbed and is of high conservation value. 6. Altitudinal trends were evident with a small number of species only occurring at the high altitudes and others only at low altitudes. Only a few species appeared to occur at all altitudes sampled. 7. Ordination plots showed that Collembola assemblages at lower altitude sites on the Warra transect were more similar to each other than those at the higher altitude sites on Mount Weld which formed three clusters: 1100; 1200 and 1300 m; and 800, 900 and 1000 m. 8. Mount Weld sites 600 and 700 m faunas were most similar to Warra sites so forming a continuum in altitudinal zonation between Warra and Mount Weld. 9. PERMANOVA analysis of monthly pitfall catches in 2001 and 2002 showed differences between months and altitudes on both transects and that the differences between months were more distinct at the lower altitude Warra sites than on the higher altitude Mount Weld sites. This difference was particularly marked for the month of February, which was the only month surveyed in both years. 10.Much of the change in faunal assemblages along the Warra and Mount Weld altitudinal transect seemed to be the result of changes in vegetation cover. The most abrupt faunal transitions took place across the tree line between 1000 and 1100 m and a smaller change from lowland forest to subalpine woodland on the Mount Weld transect. 11.Much material in the pitfalls was in very poor condition because of the long trapping time with unsuitable preservative so could not be identified to species but rough estimates were made of numbers of individuals in each family or genus.
Health effects associated with inhalation of airborne arsenic arising from mining operations
- Martin, Rachael, Dowling, Kim, Pearce, Dora, Sillitoe, Jim, Florentine, Singarayer
- Authors: Martin, Rachael , Dowling, Kim , Pearce, Dora , Sillitoe, Jim , Florentine, Singarayer
- Date: 2014
- Type: Text , Journal article
- Relation: Geosciences (Switzerland) Vol. 4, no. 3 (2014), p. 128-175
- Full Text:
- Reviewed:
- Description: Arsenic in dust and aerosol generated by mining, mineral processing and metallurgical extraction industries, is a serious threat to human populations throughout the world. Major sources of contamination include smelting operations, coal combustion, hard rock mining, as well as their associated waste products, including fly ash, mine wastes and tailings. The number of uncontained arsenic-rich mine waste sites throughout the world is of growing concern, as is the number of people at risk of exposure. Inhalation exposures to arsenic-bearing dusts and aerosol, in both occupational and environmental settings, have been definitively linked to increased systemic uptake, as well as carcinogenic and non-carcinogenic health outcomes. It is therefore becoming increasingly important to identify human populations and sensitive sub-populations at risk of exposure, and to better understand the modes of action for pulmonary arsenic toxicity and carcinogenesis. In this paper we explore the contribution of smelting, coal combustion, hard rock mining and their associated waste products to atmospheric arsenic. We also report on the current understanding of the health effects of inhaled arsenic, citing results from various toxicological, biomedical and epidemiological studies. This review is particularly aimed at those researchers engaged in the distinct, but complementary areas of arsenic research within the multidisciplinary field of medical geology. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
- Authors: Martin, Rachael , Dowling, Kim , Pearce, Dora , Sillitoe, Jim , Florentine, Singarayer
- Date: 2014
- Type: Text , Journal article
- Relation: Geosciences (Switzerland) Vol. 4, no. 3 (2014), p. 128-175
- Full Text:
- Reviewed:
- Description: Arsenic in dust and aerosol generated by mining, mineral processing and metallurgical extraction industries, is a serious threat to human populations throughout the world. Major sources of contamination include smelting operations, coal combustion, hard rock mining, as well as their associated waste products, including fly ash, mine wastes and tailings. The number of uncontained arsenic-rich mine waste sites throughout the world is of growing concern, as is the number of people at risk of exposure. Inhalation exposures to arsenic-bearing dusts and aerosol, in both occupational and environmental settings, have been definitively linked to increased systemic uptake, as well as carcinogenic and non-carcinogenic health outcomes. It is therefore becoming increasingly important to identify human populations and sensitive sub-populations at risk of exposure, and to better understand the modes of action for pulmonary arsenic toxicity and carcinogenesis. In this paper we explore the contribution of smelting, coal combustion, hard rock mining and their associated waste products to atmospheric arsenic. We also report on the current understanding of the health effects of inhaled arsenic, citing results from various toxicological, biomedical and epidemiological studies. This review is particularly aimed at those researchers engaged in the distinct, but complementary areas of arsenic research within the multidisciplinary field of medical geology. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
- Florentine, Singarayer, Milberg, Per, Di Stefano, Julian, Westbrooke, Martin, Graz, Patrick
- Authors: Florentine, Singarayer , Milberg, Per , Di Stefano, Julian , Westbrooke, Martin , Graz, Patrick
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Arid Environments Vol. 121, no. October (2015), p. 7-14
- Full Text:
- Reviewed:
- Description: Australian arid vegetation has evolved within highly variable environments characterised by low rainfall and sporadic fire events. Episodic high rainfall events are a significant factor in plant species recruitment, but their unpredictability makes them difficult to study. We report on the response of vascular plants to a major rainfall event and flood in an arid region of south-eastern Australia. Fire that occurred two months before the flood was incorporated into the study. Paired fenced and unfenced plots were established at control locations and also in areas that had been either flooded, burnt, or flooded and burnt. Objectives were to quantify the long-term effects of fire, flood and vertebrate herbivory, and their interactions, on vegetation composition, plant life forms and species diversity. We found that relative to controls (i) there was a significant effect of flooding on vegetation composition, (ii) changes in life form abundance were driven by flooding and grazing, (iii) there was a strong positive relationship between grazer exclusion and species diversity that was maintained over time and (iv) there was little effect of fire. Understanding the long-term effects of both natural disturbances and vertebrate herbivory will benefit plant conservation in the arid zone. © 2015 Elsevier Ltd.
Detecting the seeds of Nassella neesiana in large round hay bales, by means of non-destructive core sampling
- Weller, Sandra, Florentine, Singarayer, Sillitoe, Jim, Grech, Charles, McLaren, David, Chauhan, Bhagirath
- Authors: Weller, Sandra , Florentine, Singarayer , Sillitoe, Jim , Grech, Charles , McLaren, David , Chauhan, Bhagirath
- Date: 2015
- Type: Text , Journal article
- Relation: Plos One Vol. 10, no. 9 (2015), p.
- Full Text:
- Reviewed:
- Description: In the last three decades or so there has been a significant increase in fodder trading, both in terms of the quantity of fodder traded and in terms of its economic value to the industry. Often, this fodder type may be supplied free of charge to graziers in distress due to circumstances that follow natural disasters such as bushfires, drought, and flood. However, because of the obvious urgency arising from these situations, it is suspected that much relief fodder may unintentionally pose an elevated risk for dispersal of weeds since it may be supplied from pasture not normally used for trade in fodder, and therefore is of unknown quality. Previous destructive method to detect weed propagules in bales of fodder are cumbersome, time consuming and of limited ecological and statistical value. Therefore, objective of this paper was to development of a convenient method to assess round pasture hay bales for the presence of weed propagules, to prevent unintentional spread of noxious species in hay bales. To examine this objective known quantity of seeds were added in a series of distributions to bales of seed free pasture hay, and a positive correlation for the amount of seed added per bale with that recovered in core samples was observed. Whilst the number of seeds detected per bale varied according to the distribution of seeds within the bales and the number of cores analysed, the absolute detection of seeds suggests that this sampling method is worthy of further examination. In addition, a pragmatic estimation of bale remnants after stock feeding has been investigated to more closely estimate the potential size of the remaining seed bank. The authors propose that development of this approach is timely, in the light of future climatic uncertainty driving extreme weather events that increase the need for relief fodder, which can be a potential vector for the spread of noxious weed seeds.
- Authors: Weller, Sandra , Florentine, Singarayer , Sillitoe, Jim , Grech, Charles , McLaren, David , Chauhan, Bhagirath
- Date: 2015
- Type: Text , Journal article
- Relation: Plos One Vol. 10, no. 9 (2015), p.
- Full Text:
- Reviewed:
- Description: In the last three decades or so there has been a significant increase in fodder trading, both in terms of the quantity of fodder traded and in terms of its economic value to the industry. Often, this fodder type may be supplied free of charge to graziers in distress due to circumstances that follow natural disasters such as bushfires, drought, and flood. However, because of the obvious urgency arising from these situations, it is suspected that much relief fodder may unintentionally pose an elevated risk for dispersal of weeds since it may be supplied from pasture not normally used for trade in fodder, and therefore is of unknown quality. Previous destructive method to detect weed propagules in bales of fodder are cumbersome, time consuming and of limited ecological and statistical value. Therefore, objective of this paper was to development of a convenient method to assess round pasture hay bales for the presence of weed propagules, to prevent unintentional spread of noxious species in hay bales. To examine this objective known quantity of seeds were added in a series of distributions to bales of seed free pasture hay, and a positive correlation for the amount of seed added per bale with that recovered in core samples was observed. Whilst the number of seeds detected per bale varied according to the distribution of seeds within the bales and the number of cores analysed, the absolute detection of seeds suggests that this sampling method is worthy of further examination. In addition, a pragmatic estimation of bale remnants after stock feeding has been investigated to more closely estimate the potential size of the remaining seed bank. The authors propose that development of this approach is timely, in the light of future climatic uncertainty driving extreme weather events that increase the need for relief fodder, which can be a potential vector for the spread of noxious weed seeds.
The need for speed: Timely prevention of the dispersal of noxious weeds in relief fodder using efficient sampling procedures
- Weller, Sandra, Florentine, Singarayer, Sillitoe, Jim, Grech, Charles, McLaren, David, Chauhan, Bhagirath
- Authors: Weller, Sandra , Florentine, Singarayer , Sillitoe, Jim , Grech, Charles , McLaren, David , Chauhan, Bhagirath
- Date: 2015
- Type: Text , Journal article
- Relation: Crop Protection Vol. 70, no. (2015), p. 21-27
- Full Text:
- Reviewed:
- Description: Invasive and noxious weeds are well known as a pervasive problem, imposing significant economic burdens on all areas of agriculture. Whilst there are multiple possible pathways of weed dispersal in this industry, of particular interest to this discussion is the unintended dispersal of weed seeds within fodder. During periods of drought or following natural disasters such as wild fire or flood, there arises the urgent need for 'relief' fodder to ensure survival and recovery of livestock. In emergency situations, relief fodder may be sourced from widely dispersed geographic regions, and some of these regions may be invaded by an extensive variety of weeds that are both exotic and detrimental to the intended destination for the fodder. Pasture hay is a common source of relief fodder and it typically consists of a mixture of grassy and broadleaf species that may include noxious weeds. When required urgently, pasture hay for relief fodder can be cut, baled, and transported over long distances in a short period of time, with little opportunity for prebaling inspection. It appears that, at the present time, there has been little effort towards rapid testing of bales, post-baling, for the presence of noxious weeds, as a measure to prevent dispersal of seeds. Published studies have relied on the analysis of relatively small numbers of bales, tested to destruction, in order to reveal seed species for identification and enumeration. The development of faster, more reliable, and non-destructive sampling methods is essential to increase the fodder industry's capacity to prevent the dispersal of noxious weeds to previously unaffected locales.
- Authors: Weller, Sandra , Florentine, Singarayer , Sillitoe, Jim , Grech, Charles , McLaren, David , Chauhan, Bhagirath
- Date: 2015
- Type: Text , Journal article
- Relation: Crop Protection Vol. 70, no. (2015), p. 21-27
- Full Text:
- Reviewed:
- Description: Invasive and noxious weeds are well known as a pervasive problem, imposing significant economic burdens on all areas of agriculture. Whilst there are multiple possible pathways of weed dispersal in this industry, of particular interest to this discussion is the unintended dispersal of weed seeds within fodder. During periods of drought or following natural disasters such as wild fire or flood, there arises the urgent need for 'relief' fodder to ensure survival and recovery of livestock. In emergency situations, relief fodder may be sourced from widely dispersed geographic regions, and some of these regions may be invaded by an extensive variety of weeds that are both exotic and detrimental to the intended destination for the fodder. Pasture hay is a common source of relief fodder and it typically consists of a mixture of grassy and broadleaf species that may include noxious weeds. When required urgently, pasture hay for relief fodder can be cut, baled, and transported over long distances in a short period of time, with little opportunity for prebaling inspection. It appears that, at the present time, there has been little effort towards rapid testing of bales, post-baling, for the presence of noxious weeds, as a measure to prevent dispersal of seeds. Published studies have relied on the analysis of relatively small numbers of bales, tested to destruction, in order to reveal seed species for identification and enumeration. The development of faster, more reliable, and non-destructive sampling methods is essential to increase the fodder industry's capacity to prevent the dispersal of noxious weeds to previously unaffected locales.
An investigation of the effects of stage of ensilage on Nassella neesiana seeds, for reducing seed viability and injury to livestock
- Weller, Sandra, Florentine, Singarayer, Sillitoe, Jim, Grech, Charles, McLaren, David
- 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
- Full Text:
- Reviewed:
- 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.
- 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
- Full Text:
- Reviewed:
- 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.
Glyphosate Resistance of C-3 and C-4 Weeds under Rising Atmospheric CO2
- Fernando, Nimesha, Manalil, Sudheesh, Florentine, Singarayer, Chauhan, Bhagirath, Seneweera, Saman
- Authors: Fernando, Nimesha , Manalil, Sudheesh , Florentine, Singarayer , Chauhan, Bhagirath , Seneweera, Saman
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Frontiers in Plant Science Vol. 7, no. (Jun 2016), p. 1-11
- Full Text:
- Reviewed:
- Description: The present paper reviews current knowledge on how changes of plant metabolism under elevated CO2 concentrations (e[CO2]) can affect the development of the glyphosate resistance of C-3 and C-4 weeds. Among the chemical herbicides, glyphosate, which is a non-selective and post-emergence herbicide, is currently the most widely used herbicide in global agriculture. As a consequence, glyphosate resistant weeds, particularly in major field crops, are a widespread problem and are becoming a significant challenge to future global food production. Of particular interest here it is known that the biochemical processes involved in photosynthetic pathways of C-3 and C-4 plants are different, which may have relevance to their competitive development under changing environmental conditions. It has already been shown that plant anatomical, morphological, and physiological changes under e[CO2] can be different, based on (i) the plant's functional group, (ii) the available soil nutrients, and (iii) the governing water status. In this respect, C-3 species are likely to have a major developmental advantage under a CO2 rich atmosphere, by being able to capitalize on the overall stimulatory effect of e[CO2]. For example, many tropical weed grass species fix CO2 from the atmosphere via the C-4 photosynthetic pathway, which is a complex anatomical and biochemical variant of the C-3 pathway. Thus, based on our current knowledge of CO2 fixing, it would appear obvious that the development of a glyphosate-resistant mechanism would be easier under an e[CO2] in C-3 weeds which have a simpler photosynthetic pathway, than for C-4 weeds. However, notwithstanding this logical argument, a better understanding of the biochemical, genetic, and molecular measures by which plants develop glyphosate resistance and how e[CO2] affects these measures will be important before attempting to innovate sustainable technology to manage the glyphosate-resistant evolution of weeds under e[CO2]. Such information will be of essential in managing weed control by herbicide use, and to thus ensure an increase in global food production in the event of increased atmospheric [CO2] levels.
- Authors: Fernando, Nimesha , Manalil, Sudheesh , Florentine, Singarayer , Chauhan, Bhagirath , Seneweera, Saman
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Frontiers in Plant Science Vol. 7, no. (Jun 2016), p. 1-11
- Full Text:
- Reviewed:
- Description: The present paper reviews current knowledge on how changes of plant metabolism under elevated CO2 concentrations (e[CO2]) can affect the development of the glyphosate resistance of C-3 and C-4 weeds. Among the chemical herbicides, glyphosate, which is a non-selective and post-emergence herbicide, is currently the most widely used herbicide in global agriculture. As a consequence, glyphosate resistant weeds, particularly in major field crops, are a widespread problem and are becoming a significant challenge to future global food production. Of particular interest here it is known that the biochemical processes involved in photosynthetic pathways of C-3 and C-4 plants are different, which may have relevance to their competitive development under changing environmental conditions. It has already been shown that plant anatomical, morphological, and physiological changes under e[CO2] can be different, based on (i) the plant's functional group, (ii) the available soil nutrients, and (iii) the governing water status. In this respect, C-3 species are likely to have a major developmental advantage under a CO2 rich atmosphere, by being able to capitalize on the overall stimulatory effect of e[CO2]. For example, many tropical weed grass species fix CO2 from the atmosphere via the C-4 photosynthetic pathway, which is a complex anatomical and biochemical variant of the C-3 pathway. Thus, based on our current knowledge of CO2 fixing, it would appear obvious that the development of a glyphosate-resistant mechanism would be easier under an e[CO2] in C-3 weeds which have a simpler photosynthetic pathway, than for C-4 weeds. However, notwithstanding this logical argument, a better understanding of the biochemical, genetic, and molecular measures by which plants develop glyphosate resistance and how e[CO2] affects these measures will be important before attempting to innovate sustainable technology to manage the glyphosate-resistant evolution of weeds under e[CO2]. Such information will be of essential in managing weed control by herbicide use, and to thus ensure an increase in global food production in the event of increased atmospheric [CO2] levels.
Investigations into the effects of elevated carbon dioxide and drought on the growth and physiology of carpet weed (Galenia pubescens Eckl. & Zeyh.)
- Mahmood, Ako, Florentine, Singarayer, Fernando, Nimesha, Wright, Wendy, Palmer, Grant, McLaren, David, Sillitoe, Jim
- Authors: Mahmood, Ako , Florentine, Singarayer , Fernando, Nimesha , Wright, Wendy , Palmer, Grant , McLaren, David , Sillitoe, Jim
- Date: 2016
- Type: Text , Conference proceedings
- Relation: 20th Australasian Weeds Conference 2016; Perth, Western Australia; 11th-15th September 2016 p. 347-350
- Full Text:
- Reviewed:
- Description: The present study aimed to examine the interactive effects of elevated atmospheric CO2 concentration and drought stress on the growth and some of the physiological processes of Galenia pubescens. Photosynthetic rate of plants increased under elevated CO2 concentration, however drought caused significant reduction in net photosynthetic rate by (45% in 400 ppm CO2) and (27% in 700 ppm CO2) after five days simulating the drought treatment when compared with well-watered plants. Plants grown under elevated CO2 level and well-watered produced a greater biomass (17.5 ± 0.5 g per plant) compared to the plants which were grown under the ambient CO2 concentration.
- Authors: Mahmood, Ako , Florentine, Singarayer , Fernando, Nimesha , Wright, Wendy , Palmer, Grant , McLaren, David , Sillitoe, Jim
- Date: 2016
- Type: Text , Conference proceedings
- Relation: 20th Australasian Weeds Conference 2016; Perth, Western Australia; 11th-15th September 2016 p. 347-350
- Full Text:
- Reviewed:
- Description: The present study aimed to examine the interactive effects of elevated atmospheric CO2 concentration and drought stress on the growth and some of the physiological processes of Galenia pubescens. Photosynthetic rate of plants increased under elevated CO2 concentration, however drought caused significant reduction in net photosynthetic rate by (45% in 400 ppm CO2) and (27% in 700 ppm CO2) after five days simulating the drought treatment when compared with well-watered plants. Plants grown under elevated CO2 level and well-watered produced a greater biomass (17.5 ± 0.5 g per plant) compared to the plants which were grown under the ambient CO2 concentration.
Emerging challenges and opportunities for education and research in weed science
- Chauhan, Bhagirath, Matloob, Amar, Mahajan, Gulshan, Aslam, Farhena, Florentine, Singarayer, Jha, Prashant
- Authors: Chauhan, Bhagirath , Matloob, Amar , Mahajan, Gulshan , Aslam, Farhena , Florentine, Singarayer , Jha, Prashant
- Date: 2017
- Type: Text , Journal article
- Relation: Frontiers in Plant Science Vol. 8, no. (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: In modern agriculture, with more emphasis on high input systems, weed problems are likely to increase and become more complex. With heightened awareness of adverse effects of herbicide residues on human health and environment and the evolution of herbicide-resistant weed biotypes, a significant focus within weed science has now shifted to the development of eco-friendly technologies with reduced reliance on herbicides. Further, with the large-scale adoption of herbicide-resistant crops, and uncertain climatic optima under climate change, the problems for weed science have become multi-faceted. To handle these complex weed problems, a holistic line of action with multi-disciplinary approaches is required, including adjustments to technology, management practices, and legislation. Improved knowledge of weed ecology, biology, genetics, and molecular biology is essential for developing sustainable weed control practices. Additionally, judicious use of advanced technologies, such as site-specific weed management systems and decision support modeling, will play a significant role in reducing costs associated with weed control. Further, effective linkages between farmers and weed researchers will be necessary to facilitate the adoption of technological developments. To meet these challenges, priorities in research need to be determined and the education system for weed science needs to be reoriented. In respect of the latter imperative, closer collaboration between weed scientists and other disciplines can help in defining and solving the complex weed management challenges of the 21st century. This consensus will provide more versatile and diverse approaches to innovative teaching and training practices, which will be needed to prepare future weed science graduates who are capable of handling the anticipated challenges of weed science facing in contemporary agriculture. To build this capacity, mobilizing additional funding for both weed research and weed management education is essential. © 2017 Chauhan, Matloob, Mahajan, Aslam, Florentine and Jha.
- Authors: Chauhan, Bhagirath , Matloob, Amar , Mahajan, Gulshan , Aslam, Farhena , Florentine, Singarayer , Jha, Prashant
- Date: 2017
- Type: Text , Journal article
- Relation: Frontiers in Plant Science Vol. 8, no. (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: In modern agriculture, with more emphasis on high input systems, weed problems are likely to increase and become more complex. With heightened awareness of adverse effects of herbicide residues on human health and environment and the evolution of herbicide-resistant weed biotypes, a significant focus within weed science has now shifted to the development of eco-friendly technologies with reduced reliance on herbicides. Further, with the large-scale adoption of herbicide-resistant crops, and uncertain climatic optima under climate change, the problems for weed science have become multi-faceted. To handle these complex weed problems, a holistic line of action with multi-disciplinary approaches is required, including adjustments to technology, management practices, and legislation. Improved knowledge of weed ecology, biology, genetics, and molecular biology is essential for developing sustainable weed control practices. Additionally, judicious use of advanced technologies, such as site-specific weed management systems and decision support modeling, will play a significant role in reducing costs associated with weed control. Further, effective linkages between farmers and weed researchers will be necessary to facilitate the adoption of technological developments. To meet these challenges, priorities in research need to be determined and the education system for weed science needs to be reoriented. In respect of the latter imperative, closer collaboration between weed scientists and other disciplines can help in defining and solving the complex weed management challenges of the 21st century. This consensus will provide more versatile and diverse approaches to innovative teaching and training practices, which will be needed to prepare future weed science graduates who are capable of handling the anticipated challenges of weed science facing in contemporary agriculture. To build this capacity, mobilizing additional funding for both weed research and weed management education is essential. © 2017 Chauhan, Matloob, Mahajan, Aslam, Florentine and Jha.
Weeds in a changing climate : Vulnerabilities, consequences, and implications for future weed management
- Ramesh, Kulasekaran, Matloob, Amar, Aslam, Farhena, Florentine, Singarayer, Chauhan, Bhagirath
- Authors: Ramesh, Kulasekaran , Matloob, Amar , Aslam, Farhena , Florentine, Singarayer , Chauhan, Bhagirath
- Date: 2017
- Type: Text , Journal article
- Relation: Frontiers in Plant Science Vol. 8, no. (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: Whilst it is agreed that climate change will impact on the long-term interactions between crops and weeds, the results of this impact are far from clear. We suggest that a thorough understanding of weed dominance and weed interactions, depending on crop and weed ecosystems and crop sequences in the ecosystem, will be the key determining factor for successful weed management. Indeed, we claim that recent changes observed throughout the world within the weed spectrum in different cropping systems which were ostensibly related to climate change, warrant a deeper examination of weed vulnerabilities before a full understanding is reached. For example, the uncontrolled establishment of weeds in crops leads to a mixed population, in terms of C3 and C4 pathways, and this poses a considerable level of complexity for weed management. There is a need to include all possible combinations of crops and weeds while studying the impact of climate change on crop-weed competitive interactions, since, from a weed management perspective, C4 weeds would flourish in the increased temperature scenario and pose serious yield penalties. This is particularly alarming as a majority of the most competitive weeds are C4 plants. Although CO2 is considered as a main contributing factor for climate change, a few Australian studies have also predicted differing responses of weed species due to shifts in rainfall patterns. Reduced water availability, due to recurrent and unforeseen droughts, would alter the competitive balance between crops and some weed species, intensifying the crop-weed competition pressure. Although it is recognized that the weed pressure associated with climate change is a significant threat to crop production, either through increased temperatures, rainfall shift, and elevated CO2 levels, the current knowledge of this effect is very sparse. A few models that have attempted to predict these interactions are discussed in this paper, since these models could play an integral role in developing future management programs for future weed threats. This review has presented a comprehensive discussion of the recent research in this area, and has identified key deficiencies which need further research in crop-weed eco-systems to formulate suitable control measures before the real impacts of climate change set in. © 2017 Ramesh, Matloob, Aslam, Florentine and Chauhan.
- Authors: Ramesh, Kulasekaran , Matloob, Amar , Aslam, Farhena , Florentine, Singarayer , Chauhan, Bhagirath
- Date: 2017
- Type: Text , Journal article
- Relation: Frontiers in Plant Science Vol. 8, no. (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: Whilst it is agreed that climate change will impact on the long-term interactions between crops and weeds, the results of this impact are far from clear. We suggest that a thorough understanding of weed dominance and weed interactions, depending on crop and weed ecosystems and crop sequences in the ecosystem, will be the key determining factor for successful weed management. Indeed, we claim that recent changes observed throughout the world within the weed spectrum in different cropping systems which were ostensibly related to climate change, warrant a deeper examination of weed vulnerabilities before a full understanding is reached. For example, the uncontrolled establishment of weeds in crops leads to a mixed population, in terms of C3 and C4 pathways, and this poses a considerable level of complexity for weed management. There is a need to include all possible combinations of crops and weeds while studying the impact of climate change on crop-weed competitive interactions, since, from a weed management perspective, C4 weeds would flourish in the increased temperature scenario and pose serious yield penalties. This is particularly alarming as a majority of the most competitive weeds are C4 plants. Although CO2 is considered as a main contributing factor for climate change, a few Australian studies have also predicted differing responses of weed species due to shifts in rainfall patterns. Reduced water availability, due to recurrent and unforeseen droughts, would alter the competitive balance between crops and some weed species, intensifying the crop-weed competition pressure. Although it is recognized that the weed pressure associated with climate change is a significant threat to crop production, either through increased temperatures, rainfall shift, and elevated CO2 levels, the current knowledge of this effect is very sparse. A few models that have attempted to predict these interactions are discussed in this paper, since these models could play an integral role in developing future management programs for future weed threats. This review has presented a comprehensive discussion of the recent research in this area, and has identified key deficiencies which need further research in crop-weed eco-systems to formulate suitable control measures before the real impacts of climate change set in. © 2017 Ramesh, Matloob, Aslam, Florentine and Chauhan.
Characterizing selected soil attributes of different land-use management to assess reforestation benefits of deforested riparian buffers
- Rasiah, Velu, Florentine, Singarayer
- Authors: Rasiah, Velu , Florentine, Singarayer
- Date: 2018
- Type: Text , Journal article
- Relation: Ecological Processes Vol. 7, no. 1 (2018), p. 1-12
- Full Text:
- Reviewed:
- Description: Introduction: The information available on the sensitivity of soil biotic and abiotic attributes, which can be used to track the impact of reforestation in riparian buffers, is often insufficient to refine management practices and convince stakeholders of the benefits of reforestation. Methods: In this study, conducted in Victoria, Australia, the changes in soil biotic and abiotic attributes, organic carbon (OC), mineral nitrogen (MN), total dissolved solutes (TDS) and pH were characterised to assess the impact of land-use change from bare riparian (BR) to reforested riparian (RR). Additionally, the benefits of revegetating a deforested creek bank with regard to salinity abatement and C-sequestration potentials were assessed. Results: The TDS depletion in the RR strips varied spatiotemporally from 65 to 169 mg/L, the net OC deposition from 16 to 19 g C/kg soil and MN deposition from 1.2 to 2.1 g N/kg soil, respectively. Additionally, the net changes in pH from alkaline to near neutral condition varied by 0.4 to 1.0 pH units. Approximately 30% to 60% of the net OC depletion after deforestation was redeposited under RR over 3 to 6 years. The TDS depletion after land-use changed from BR to RR ranged from 15 to 32% over 3 to 6 years. Conclusion: The soil attributes OC, MN and TDS characteristics under different land-use practices varied spatiotemporally. This information may be useful to convince stakeholders to undertake reforestation of creek banks for salinity abatement, and that change in land-use has the potential to increase C sequestration at a farm scale.
- Authors: Rasiah, Velu , Florentine, Singarayer
- Date: 2018
- Type: Text , Journal article
- Relation: Ecological Processes Vol. 7, no. 1 (2018), p. 1-12
- Full Text:
- Reviewed:
- Description: Introduction: The information available on the sensitivity of soil biotic and abiotic attributes, which can be used to track the impact of reforestation in riparian buffers, is often insufficient to refine management practices and convince stakeholders of the benefits of reforestation. Methods: In this study, conducted in Victoria, Australia, the changes in soil biotic and abiotic attributes, organic carbon (OC), mineral nitrogen (MN), total dissolved solutes (TDS) and pH were characterised to assess the impact of land-use change from bare riparian (BR) to reforested riparian (RR). Additionally, the benefits of revegetating a deforested creek bank with regard to salinity abatement and C-sequestration potentials were assessed. Results: The TDS depletion in the RR strips varied spatiotemporally from 65 to 169 mg/L, the net OC deposition from 16 to 19 g C/kg soil and MN deposition from 1.2 to 2.1 g N/kg soil, respectively. Additionally, the net changes in pH from alkaline to near neutral condition varied by 0.4 to 1.0 pH units. Approximately 30% to 60% of the net OC depletion after deforestation was redeposited under RR over 3 to 6 years. The TDS depletion after land-use changed from BR to RR ranged from 15 to 32% over 3 to 6 years. Conclusion: The soil attributes OC, MN and TDS characteristics under different land-use practices varied spatiotemporally. This information may be useful to convince stakeholders to undertake reforestation of creek banks for salinity abatement, and that change in land-use has the potential to increase C sequestration at a farm scale.
Effect of environmental factors on the germination and emergence of Salvia verbenaca L. cultivars (verbenaca and vernalis) : An invasive species in semi-arid and arid rangeland regions
- Javaid, Muhammad, Florentine, Singarayer, Ali, Hafiz, Weller, Sandra
- Authors: Javaid, Muhammad , Florentine, Singarayer , Ali, Hafiz , Weller, Sandra
- Date: 2018
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 13, no. 3 (2018), p. 1-20
- Full Text:
- Reviewed:
- Description: Salvia verbenaca (wild sage) is a commonly cultivated herbal medicine plant, which is native to the Mediterranean climate regions of Europe, Africa, Asia and the Middle East. However, it has become an invasive species in semi-arid and arid regions of southern Australia. Two varieties are present in this region, var. verbenaca and var. vernalis, each of which can be distinguished by differences in morphology and flowering period. Following trials to determine the optimum temperate regime for germination and response to light and dark, seeds of both varieties were tested for their response to variations in pH, moisture stress, salinity, and burial depth. The temperature and light trial was carried out using three different temperature regimes; 30/20C, 25/15C and 20/12C, and two light regimes; 12 hours light/12 hours dark and 24 hours dark, with var. vernalis responding to relatively higher temperatures than var. verbenaca. The germination rate of neither species was significantly inhibited by complete darkness when compared to rates under periodic light exposure. Both varieties germinated at near optimum rates strongly to very strongly in all pH buffer solutions, from pH 5 to pH 10, but they responded most strongly at neutral pH. Var. vernalis showed slightly more tolerance to reduced moisture availability, moderate to strong salinity, and burial depth, compared to var. verbenaca. However, even a fairly shallow burial depth of 2 cm completely inhibited germination of both varieties. Thus, in circumstances where both varieties are present in a soil seedbank, var. vernalis could be expected to establish in more challenging conditions, where moisture is limited and salinity is ‘moderate to high’, implying that it is a more serious threat for invasive weed in conditions where crop plants are already challenged.
- Authors: Javaid, Muhammad , Florentine, Singarayer , Ali, Hafiz , Weller, Sandra
- Date: 2018
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 13, no. 3 (2018), p. 1-20
- Full Text:
- Reviewed:
- Description: Salvia verbenaca (wild sage) is a commonly cultivated herbal medicine plant, which is native to the Mediterranean climate regions of Europe, Africa, Asia and the Middle East. However, it has become an invasive species in semi-arid and arid regions of southern Australia. Two varieties are present in this region, var. verbenaca and var. vernalis, each of which can be distinguished by differences in morphology and flowering period. Following trials to determine the optimum temperate regime for germination and response to light and dark, seeds of both varieties were tested for their response to variations in pH, moisture stress, salinity, and burial depth. The temperature and light trial was carried out using three different temperature regimes; 30/20C, 25/15C and 20/12C, and two light regimes; 12 hours light/12 hours dark and 24 hours dark, with var. vernalis responding to relatively higher temperatures than var. verbenaca. The germination rate of neither species was significantly inhibited by complete darkness when compared to rates under periodic light exposure. Both varieties germinated at near optimum rates strongly to very strongly in all pH buffer solutions, from pH 5 to pH 10, but they responded most strongly at neutral pH. Var. vernalis showed slightly more tolerance to reduced moisture availability, moderate to strong salinity, and burial depth, compared to var. verbenaca. However, even a fairly shallow burial depth of 2 cm completely inhibited germination of both varieties. Thus, in circumstances where both varieties are present in a soil seedbank, var. vernalis could be expected to establish in more challenging conditions, where moisture is limited and salinity is ‘moderate to high’, implying that it is a more serious threat for invasive weed in conditions where crop plants are already challenged.
Environmental factors effecting the germination and seedling emergence of two populations of an aggressive agricultural weed; Nassella trichotoma
- Humphries, Talia, Chauhan, Bhagirath, Florentine, Singarayer
- Authors: Humphries, Talia , Chauhan, Bhagirath , Florentine, Singarayer
- Date: 2018
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 13, no. 7 (2018), p. 1-25
- Full Text:
- Reviewed:
- Description: Nassella trichotoma (Nees) Hack. ex Arechav. (Serrated tussock) is an aggressive globally significant weed to agricultural and natural ecosystems. Herbicide resistant populations of this C3 perennial weed have emerged, increasing the need for effective wide-scale cultural control strategies. A thorough seed ecology study on two spatially distinct populations of N. trichotoma was conducted on this weed to identify differences in important environmental factors (drought, salinity, alternating temperature, photoperiod, burial depth, soil pH, artificial seed aging, and radiant heat) which influence seed dormancy. Seeds were collected from two spatially distinct populations; Gnarwarre (38 O 9’ 8.892’’ S, 144 O 7’ 38.784’’ E) and Ingliston (37O 40’ 4.44’’ S, 144 O 18’ 39.24’’ E) in December 2016 and February 2017, respectively. Twenty sterilized seeds were placed into Petri dishes lined with a single Whatman® No. 10 filter paper dampened with the relevant treatments solution and then incubated under the identified optimal alternating temperature and photoperiod regime of 25C/ 15C (light/dark, 12h/12h). For the burial depth treatment, 20 seeds were placed into plastic containers (10cm in diameter and 6cm in depth) and buried to the relevant depth in sterilized soil. All trials were monitored for 30 days and germination was indicated by 5mm exposure of the radicle and emergence was indicated by the exposure of the cotyledon. Each treatment had three replicates for each population, and each treatment was repeated to give a total of six replicates per treatment, per population. Nassella trichotoma was identified to be non-photoblastic, with germination (%) being similar under alternating light and dark and complete darkness conditions. With an increase of osmotic potential and salinity, a significant decline in germination was observed. There was no effect of pH on germination. Exposure to a radiant heat of 120C for 9 minutes resulted in the lowest germination in the Ingliston population (33%) and the Gnarwarre population (60%). In the burial depth treatment, the Ingliston population and the Gnarwarre population had highest emergence of 75% and 80%, respectively at a depth of 1cm. Variation between the two populations was observed for the burial depth treatments; Gnarwarre had greater emergence than Ingliston from the 4cm burial depth, while Ingliston had greater emergence at the soil surface than Gnarwarre. The Gnarwarre population had greater overall germination than Ingliston, which could be attributed to the greater seed mass (0.86mg compared to 0.76mg, respectively). This study identifies that spatial variations in N. trichotoma’s seed ecology are present between spatially distinct populations.
- Authors: Humphries, Talia , Chauhan, Bhagirath , Florentine, Singarayer
- Date: 2018
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 13, no. 7 (2018), p. 1-25
- Full Text:
- Reviewed:
- Description: Nassella trichotoma (Nees) Hack. ex Arechav. (Serrated tussock) is an aggressive globally significant weed to agricultural and natural ecosystems. Herbicide resistant populations of this C3 perennial weed have emerged, increasing the need for effective wide-scale cultural control strategies. A thorough seed ecology study on two spatially distinct populations of N. trichotoma was conducted on this weed to identify differences in important environmental factors (drought, salinity, alternating temperature, photoperiod, burial depth, soil pH, artificial seed aging, and radiant heat) which influence seed dormancy. Seeds were collected from two spatially distinct populations; Gnarwarre (38 O 9’ 8.892’’ S, 144 O 7’ 38.784’’ E) and Ingliston (37O 40’ 4.44’’ S, 144 O 18’ 39.24’’ E) in December 2016 and February 2017, respectively. Twenty sterilized seeds were placed into Petri dishes lined with a single Whatman® No. 10 filter paper dampened with the relevant treatments solution and then incubated under the identified optimal alternating temperature and photoperiod regime of 25C/ 15C (light/dark, 12h/12h). For the burial depth treatment, 20 seeds were placed into plastic containers (10cm in diameter and 6cm in depth) and buried to the relevant depth in sterilized soil. All trials were monitored for 30 days and germination was indicated by 5mm exposure of the radicle and emergence was indicated by the exposure of the cotyledon. Each treatment had three replicates for each population, and each treatment was repeated to give a total of six replicates per treatment, per population. Nassella trichotoma was identified to be non-photoblastic, with germination (%) being similar under alternating light and dark and complete darkness conditions. With an increase of osmotic potential and salinity, a significant decline in germination was observed. There was no effect of pH on germination. Exposure to a radiant heat of 120C for 9 minutes resulted in the lowest germination in the Ingliston population (33%) and the Gnarwarre population (60%). In the burial depth treatment, the Ingliston population and the Gnarwarre population had highest emergence of 75% and 80%, respectively at a depth of 1cm. Variation between the two populations was observed for the burial depth treatments; Gnarwarre had greater emergence than Ingliston from the 4cm burial depth, while Ingliston had greater emergence at the soil surface than Gnarwarre. The Gnarwarre population had greater overall germination than Ingliston, which could be attributed to the greater seed mass (0.86mg compared to 0.76mg, respectively). This study identifies that spatial variations in N. trichotoma’s seed ecology are present between spatially distinct populations.