The extent of Mission grasses and Gamba Grass in the Darwin region of Australia's Northern Territory

2002 ◽  
Vol 8 (4) ◽  
pp. 281 ◽  
Author(s):  
Louise Kean ◽  
Owen Price
Keyword(s):  
Land Tenure ◽  
Hot Spots ◽  
Northern Australia ◽  
Weed Species ◽  
Small Areas ◽  
Major Threat ◽  
Potential Habitat ◽  
Potential Source ◽  
Andropogon Gayanus ◽  
Prompt Action

Mission grasses Pennisetum polystachion (L.) Schult. and P. pedicellatum (Trin) and Gamba Grass Andropogon gayanus (Kunth) are three weed species that are thought to be spreading rapidly in the vicinity of Darwin and may pose a major threat to ecosystems in northern Australia. The distribution of the species was assessed from a vehicle along 913 km of roads near Darwin. The study provided data on the potential source of further spread and an analysis of the potential habitat of the weeds. For analysis, roadsides were divided up into 200 m cells and the distributions of the grasses were compared against land tenure and broad land unit maps, Mission grasses were present in approximately 52% of cells, and were particularly common around the rural residential/horticultural area of Humpty Doo. They occurred equally commonly in all broad land units, but differed among tenures, being particularly common on freehold land. Gamba Grass occurred in 15% of cells, with hot spots in a number of areas. It was most common on freehold land, and was rare on conservation reserves. It also showed an association with broad land units reflecting wetter areas. Mission grasses are so widespread in the Darwin region that control can only be contemplated in very small areas requiring frequent treatment of re-invading plants. It may be possible to control Gamba Grass in conservation reserves and Crown land if prompt action is taken. For all three species, preventing their spread to new areas should be a high priority.

A Method for Assessing Herbicide Performance in Small Plot Experiments

Weed Science ◽  
1977 ◽  
Vol 25 (5) ◽  
pp. 386-389 ◽  
Author(s):  
A.S. Hamill ◽  
P.B. Marriage ◽  
G. Friesen
Keyword(s):  
Individual Species ◽  
Weed Species ◽  
Rating Systems ◽  
Small Areas ◽  
Retrieval Systems ◽  
Weed Cover ◽  
Weed Plants ◽  
Plot Area ◽  
Small Plot ◽  
Grass Weed

A method is described that provides an accurate and useful assessment of herbicide performance in small plot experiments. This method is an extension of previous rating systems and provides an assessment of the control of individual species through an estimation of the percentage that each contributes to the total broadleaf or grass weed cover on the whole plot area. It permits data collection on individual weed species but is less time-consuming than counting individual plants and it takes into account the size and vigor of individual weed plants as well as their relative abundance. Further, the system allows tabulation of data from across the entire plot rather than from small areas within the plot. The data can be readily entered into various computerized retrieval systems.

RESULT OF HERBICIDES APPLIED AGAINST OF WEEDS IN SOYBEAN FIELD

2015 ◽  
Vol 13 (2) ◽  
pp. 76-79
Author(s):  
O Ariunaa ◽  
M Otgonsuren
Keyword(s):  
Chenopodium Album ◽  
Herbicide Application ◽  
Weed Species ◽  
Convolvulus Arvensis ◽  
Couch Grass ◽  
Soybean Field ◽  
Small Areas ◽  
Polygonum Convolvulus ◽  
Perennial Weeds ◽  
Field Bindweed

Herbicides, if used properly, are safe and effective in controlling weeds in soybean. The choice of herbicide, however, depends on the predominant weed species and the availability of the herbicide. Chemical control is currently the most widely used control for soybean crops, due to its ease of control and to the small areas planted in Mongolia. In the soybean field the 15species of weeds belonging to 9 families, 12 genus including 62.5 % annual, 37.5%perennial weeds are distributed.The major grassy weeds; Common millet-(Panicummiliaceum L), Couch grass-(Agropyronrepens L), Bristlegrass-(Seteriaviridis L) sp and broadleaved weeds Redroot Pigweed-(Amaranthtusretro flexus),lambs guarters-(Chenopodium album), AristateGoosfoot-(Chenopodiumaristatum L), Black bindweed-(Polygonum convolvulus), Mallow weed-(Malvamochileviensis Down), Field bindweed-(Convolvulus arvensis), Bristhly thistle-(Cirsiumsetosum ), Dwarf bifurcate cinquefoil -(Potentillabifurca), Perennial Sowthisle-(Sonchusarvensis L) weeds have been distributed in the soybean field.In soybean field the Forward herbicide were applied in doses of 1.0-1.2l/ha have reduced the number of weeds by 90.1-91.6%, weight by 59.5-66.1% and super herbicide Gallantsuper applied in doses of 0.45-0.65l/ha have reduced the number of weeds by 91.0-95.0%, weight by 39.5-59.8% while Cobra herbicide applied in doses of 0.45-0.55l/ha used in broadleaved weed distributed field, have reduced the number of weeds by 90.2-94.6% and weight by 42.7-50.7%. The herbicide application increased of yield hectare by 3.6-9.0 center.Mongolian Journal of Agricultural Sciences Vol.13(2) 2014: 76-79

Carbon projects and Indigenous land in northern Australia

2014 ◽  
Vol 36 (4) ◽  
pp. 389 ◽  
Author(s):  
Jeremy Dore ◽  
Christine Michael ◽  
Jeremy Russell-Smith ◽  
Maureen Tehan ◽  
Lisa Caripis
Keyword(s):  
Carbon Sequestration ◽  
Greenhouse Gases ◽  
Land Tenure ◽  
Fire Management ◽  
Clean Energy ◽  
Northern Territory ◽  
Emissions Reduction ◽  
Northern Australia ◽  
Native Title ◽  
Indigenous Land

Land activities contribute ~18% of total greenhouse gas emissions produced in Australia. To help reduce these emissions, the Carbon Farming Initiative (CFI) was implemented in 2011 to encourage land projects, which reduce the production of greenhouse gases and/or sequester carbon in the land. Prospective projects include savanna fire management and rangelands management, which have high relevance in northern Australia where Indigenous landholding is strong. This paper explores the land-tenure requirements necessary for these kinds of carbon projects to be approved by the Clean Energy Regulator. It provides an introduction to the CFI before discussing the land tenure requirements in the states of Queensland, the Northern Territory and Western Australia with respect to both emissions reduction and carbon sequestration projects. Potential issues with the current framework are highlighted, especially in relation to native title.

Mobilization of PAH from polluted seabed and uptake in the blue mussel (Mytilus edulis L.)

1995 ◽  
Vol 46 (1) ◽  
pp. 275 ◽  
Author(s):  
K Naes ◽  
T Bakke ◽  
R Konieczny
Keyword(s):  
Hot Spots ◽  
Blue Mussel ◽  
Organic Carbon Content ◽  
Overlying Water ◽  
Seabed Sediment ◽  
Potential Source ◽  
Rapid Accumulation ◽  
Polycyclic Aromatic ◽  
Natural Range ◽  
Set Up

In several Norwegian fjords that have received effluents from smelters, there are significant accumulations of polycyclic aromatic hydrocarbons (PAH) in the sediments; near the outfalls, concentrations may reach several hundred μg total PAH g-1. As the smelters are now implementing measures to clean up and reduce discharges, the accumulations from previous discharges could assume greater relative importance as a potential source. In order to give an assessment of the significance of sedimentary PAH 'hot spots' in Norwegian smelter-affected fjords, an experiment was performed in which seabed sediment sections (0.5 × 0.5 m, 1.3 to 543 μg total PAH g-1) were collected from the Oslo-, Sauda- and Sunndalsfjords and placed in an experimental set-up in which Oslofjord water taken from a depth of 40 m was passed over the sediment surfaces. The mobilization experiments indicated that a natural seabed containing 100 μg PAH g-1, and with a resuspension (due to bioturbation) within an expected natural range, might give an annual contribution to the overlying water of the order of 20 kg PAH km-2. Mussels continuously exposed to the water from the test sediments accumulated PAH in a clear response to concentrations in sediments and water and to the degree of resuspension. PAH from the Saudalsfjord were apparently more bioavailable than those from the Sunndalsfjord, and it is argued that a more rapid accumulation in the former case was stimulated by an elevated organic carbon content in the sediment.

Contrasting patterns of residency and space use of coastal sharks within a communal shark nursery

2017 ◽  
Vol 68 (8) ◽  
pp. 1501 ◽  
Author(s):  
Beverly Z. L. Oh ◽  
Michele Thums ◽  
Russ C. Babcock ◽  
Jessica J. Meeuwig ◽  
Richard D. Pillans ◽  
...  
Keyword(s):  
Marine Protected Areas ◽  
Space Use ◽  
Tidal Range ◽  
Northern Australia ◽  
Small Areas ◽  
Mobile Species ◽  
Brownian Bridges ◽  
Selection For ◽  
Carcharhinus Melanopterus ◽  
Derived Data

The benefits of marine protected areas are difficult to estimate for mobile species, but their effectiveness can be increased if essential habitats, such as nursery areas, are protected. In the present study we examined movements of juvenile blacktip reef (Carcharhinus melanopterus) and sicklefin lemon (Negaprion acutidens) sharks in a coastal nursery in northern Australia. Telemetry-derived data were modelled using Brownian bridges and overlaid with maps of habitats and no-take zones. Juvenile N. acutidens were typically residents (≥30 days) of the nursery with small areas of core space use (<1.9km2), whereas juvenile C. melanopterus were non-residents (<30 days) and used larger areas (<5.6km2). Both species exhibited positive selection for sandflats and mangroves, and avoidance of deeper lagoonal and slope habitats. Monthly patterns were examined only for resident N. acutidens, and residency decreased with increasing shark length and varied seasonally for males but not females. Space use showed weak declines with increasing tidal range, and slight increases with mean air pressure, rainfall and shark length. Protecting sandflat and vegetated habitats may increase the efficacy of no-take zones for juvenile N. acutidens, because they exhibit residency and affinity to these features. Conversely, such protection will be of limited benefit for juvenile C. melanopterus, because they exhibit low residency and broader movements.

Andropogon gayanus (Gamba Grass) Invasion Increases Fire-mediated Nitrogen Losses in the Tropical Savannas of Northern Australia

Ecosystems ◽  
2007 ◽  
Vol 11 (1) ◽  
pp. 77-88 ◽  
Author(s):  
N. A. Rossiter-Rachor ◽  
S. A. Setterfield ◽  
M. M. Douglas ◽  
L. B. Hutley ◽  
G. D. Cook
Keyword(s):  
Nitrogen Losses ◽  
Northern Australia ◽  
Tropical Savannas ◽  
Andropogon Gayanus ◽  
Grass Invasion

scholarly journals Land Tenure and Development in Northern Australia

2021 ◽  
pp. 293-308
Author(s):  
Allan P. Dale ◽  
Bruce Taylor ◽  
Marcus B. Lane
Keyword(s):  
Land Tenure ◽  
Northern Australia

scholarly journals Landscape-scale effects of homesteads, water, and dingoes on invading chital deer in Australia’s dry tropics

2019 ◽  
Author(s):  
David M Forsyth ◽  
Anthony Pople ◽  
Luke Woodford ◽  
Michael Brennan ◽  
Matt Amos ◽  
...  
Keyword(s):  
Sus Scrofa ◽  
Scale Effects ◽  
Landscape Scale ◽  
Camera Traps ◽  
Northern Australia ◽  
Mammal Species ◽  
Small Areas ◽  
Dry Tropics ◽  
Management Interventions ◽  
Axis Axis

Abstract Identifying landscape features and processes that facilitate the persistence of populations is particularly important for invasive mammal species, because it can focus management interventions on relatively small areas. We used camera traps to test predictions concerning the relative abundance of invading chital deer (Axis axis) on seven cattle ranches in northern Australia: that abundance of chital deer would be highest near permanent water and near homesteads, and that dingoes (Canis dingo) reduce abundance of chital deer. Distance from the nearest homestead determined deer abundance (as indexed by images per camera-day), with negligible abundance > 4 km from homesteads. In contrast, distance from homestead did not predict abundance of feral pigs (Sus scrofa), macropods, or dingoes. Abundance of chital deer also declined with increasing distance from water, as did feral pig abundance. There was no relationship between either macropod or dingo abundance and distance to water. The abundance of chital deer was unaffected by dingo abundance, but 75–100% of dingo scats collected within 1 km of homesteads contained chital deer. The high abundances of chital deer near homesteads are likely due to increased food quality or quantity, or protection from dingoes, but these hypotheses require further testing. We conclude that homesteads and permanent water are important determinants of the distribution and abundance of invasive chital deer in northern Australia (i.e., they are “invasion hubs” for this species). Our results suggest that, during the dry season, managers should survey for and attempt to control chital deer within 4 km of homesteads and within 3 km of water.

scholarly journals A Study of Weeds as Potential Inoculum Sources for a Tomato-Infecting Begomovirus in Central Brazil

2013 ◽  
Vol 103 (5) ◽  
pp. 436-444 ◽  
Author(s):  
S. S. Barreto ◽  
M. Hallwass ◽  
O. M. Aquino ◽  
A. K. Inoue-Nagata
Keyword(s):  
Mosaic Virus ◽  
Begomovirus Species ◽  
Yellow Mosaic Virus ◽  
Weed Species ◽  
Tomato Production ◽  
Inoculum Sources ◽  
Tomato Plants ◽  
Central Brazil ◽  
Potential Source ◽  
Biolistic Inoculation

Tomato severe rugose virus (ToSRV) is the most important begomovirus species in Brazilian tomato production. Many weeds are associated with tomato, and some are hosts of begomoviruses. Only one species of weed, Nicandra physaloides, has been found to be infected with ToSRV. In this study, four weed species were investigated for their capacity to be infected by ToSRV and serve as a potential source of inoculum for tomato. Begomoviruses from naturally infected Crotalaria spp., Euphorbia heterophylla, N. physaloides, and Sida spp. were successfully transferred to tomato plants by biolistic inoculation. ToSRV was the major virus transferred to tomato. In contrast, other begomoviruses were transferred to weeds, such as Sida micrantha mosaic virus and Euphorbia yellow mosaic virus. Furthermore, a new strain of Sida micrantha mosaic virus is reported. We also confirmed that Crotalaria spp., E. heterophylla, and Sida spp. are infected with ToSRV but at low viral titers and in mixed infections with weed-infecting begomoviruses. Thus, it was demonstrated that weeds are potential sources of ToSRV for tomato in central Brazil.

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