Title: Ecology and management of an emerging weed, Cyperus aromaticus (Navua sedge), under changing climatic conditions.
Summary: One of the most challenging issues in agricultural systems is the control of elevated populations of weed species. C. aromaticus is an emerging weed in Australia and is beginning to play a major, and increasingly important role in Australian farming, especially in the wet tropical areas of Queensland. Gaining insight into the ecological and biological characteristics of C. aromaticus will assist farmers and land managers to take suitable control actions for this species at an early stage of its invasion into new areas. The objective of this project is to better manage C. aromaticus in the wet tropics of Queensland by (i) understanding the ecology of the species, (ii) analysing the soil seed bank dynamics of spatially varied pastures infested by this species, (iii) exploring the possible long-term management options to control both above and underground spread of this weed, and (iv) determine the response of this species to various climate change scenarios. The intention of this investigation is to contribute to a significant weed management problem at a stage where intervention is cost-effective, efficient and environmentally sensitive.
Title: Submerged aquatic vegetation management techniques in a man-made shallow lake.
Summary: Managing submerged aquatic vegetation (SAV) in shallow amenity lakes is a balancing act. While aquatic plants are integral components of freshwater ecosystems and provide essential ecosystem services (water quality, water clarity, wildlife habitat, carbon uptake etc), overabundance of SAV can impair some ecosystem services and reduce amenity value (obstruct fishing, boating, swimming, reduce aesthetic etc). Many lakes in Victoria, Australia, have artificially maintained and stable water levels to provide economic and social benefits but these situations, combined with excessive nutrient inputs, also provide an ideal environment for SAV growth, leading to problematic infestations. This project seeks to understand the issues attending the native aquatic plant species Myriophyllum salsugineum in Lake Wendouree to identify the optimal area of SAV coverage for maintaining water quality and amenity value, and will develop sound management strategies to combat SAV overabundance by 1) Developing an understanding of shallow lake ecology and its driving factors. 2) Comprehensively reviewing SAV control methods including harvesting and herbicide application and developing a global synthesis for management techniques. 3) Monitoring the current ecological health of Lake Wendouree to fill in knowledge gaps via targeted sampling and identifying off-target species with metabarcoding 4) Simulating different management strategies using the European lake model PCLake+ to determine the most effective management regime. 5) Simulating herbicide application using mesocosm trials.
Title: Ecology and management of the endangered ecological community Halosarcia lylei low open shrubland in the southern Murray Darling Basin, NSW.
Summary: Halosarcia lylei low open shrubland is an endangered ecological community in far south-west New South Wales. It is a largely monospecific community, dominated by the chenopod Tecticornia lylei (formerly known as Halosarcia lylei), and occurs on the fringes and across the beds of smaller dry salt lakes in the region. Records of T. lylei are known in South Australia, Western Australia and in localised areas of north-west Victoria, however there is limited published literature on the species. In order to manage this threatened vegetation community, increased understanding is required on its distribution and the factors which influence whether it can thrive and persist into the future. This project aims to address these knowledge gaps through studies on vegetation community structure, habitat requirements, impacts of grazing, and the reproductive ability and genetic diversity of the dominant species, including comparative studies on populations in other states of Australia.
Title: Targeting the dominant weed for land-scape scale restoration of degraded grasslands; a case study with Nassella trichotoma.
Summary: Temperate grasslands throughout Australia, New Zealand and South Africa have been prolifically invaded by the South American grass, Nassella trichotoma (Serrated Tussock). This coarse, tufted-grass is having a devastating effect on agricultural and natural systems as this weed displaces native and palatable grasses, reduces soil nutrients, and can quickly form dense monocultures, making it the worst weed for reducing carrying capacity. Despite literature into its control spanning almost 70 years, this weed is still problematic. Therefore, this project will use readily available management techniques that are applicable on a land-scape scale, to target the above ground and below ground density of N. trichotoma. To reduce recruitment from the seedbank, we will investigate the longevity of this weeds seeds and make recommendations as to how long a site should be managed to prevent reinfestation. A competition study between N. trichotoma and two native grasses (a C3 and a C4) will be conducted under elevated CO2 to better anticipate ideal competitors for climate ready restoration efforts. Lastly, we will explore the possible use of spatial imagery to auto-detect new and spreading N. trichotoma populations. We hope that these findings will have broader implications and be applicable to similar degraded grasslands globally.
Title: How to control herbicide resistant weeds with innovative herbicide strategies.
Summary: Agriculture is one of the largest economical assets of Australia. Among key agricultural crops, pulses; particularly Faba beans (Vicia faba) play a major role as Australia is the number one faba bean exporter. However, maintaining this condition has become challenging due to the presence of herbicide-resistant (HR) weeds. Increasing number of HR weeds underscores the importance of addressing the problem of overuse and reliance on herbicides. But still the chemical weed control has become necessary in today’s agriculture due to laborious, tiresome and expensive traditional alternatives. As the release of new herbicide mode of actions (MOA) to the market has not occurred for last three decades, it is timely to introduce new herbicide strategies within existing herbicide MOA. Development of herbicide tolerant crops (HTC) has become another approach to control HR weeds in cropping systems. With the synergism of these two approaches, our study will focus on controlling HR R. raphanistrum with different herbicide MOA combinations in a herbicide tolerant faba bean cropping system. This project will help to understand the strength and flexibility of herbicide tolerant crops and to lay a sound set of stewardship guidelines to make faba bean more sustainable as an economically important crop.
Title: The influence of controlled burning on the remobilizing arsenic and selected metals from the soils in historic mining districts of Central Victoria, Australia.
Summary: We live in a mining affected landscape where controlled burns and intense bush fires are more and more common. The mobilization of significant quantities of arsenic, and other toxic metals during and after fire regimes that have the potential to affect ecological and human health adversely, warrants investigation.
Title: Invasion by a native Australian shrub Acacia longifolia ssp. longifolia in southeastern Australia.
Summary: Acacia longifolia ssp. longifolia is an invasive plant within the Grampians National Park. The shrub is a transformer species, which threatens the diverse, and in some cases endemic, flora of fauna of the area. This overall aim of this project is to determine the environmental factors and plant traits which may enhance the invasiveness of the species, as well as predict the future distribution and abundance of Acacia longifolia ssp. longifolia, and thus focus and create achievable and efficient management strategies.
Title: Optimising the management of invasive aquatic plants targeted for extirpation from catchments and waterways; utilising alligator weed (Alternanthera philoxeroides) as an indicator species.
Summary: This research project aims to develop effective management strategies for one of the world's most invasive aquatic weed species, alligator weed (Alternanthera philoxeroides) in an early stage of invasion, to achieve extirpation from catchments and waterways. Developing methods to manage viable fragment production post herbicide application and improving the effectiveness of detection in early stages of invasion, will result in an increased likelihood of extirpating invasive aquatic weeds that pose a biosecurity risk and reduce the impacts on agricultural productivity, social amenity and biodiversity values.
Ako Hussein Mahmood
Title: Investigations into the ecology and management of the invasive plant Galenia pubescens within the native temperate grasslands of Victoria, Australia.
Summary: Galenia pubescens (carpet weed or coastal galenia) belongs to the family Aizoaceae and is also commonly known as blanket or carpet weed. This species is a woody prostrate perennial species native to South Africa, however it has been introduced to and become well established in other localities such as California, central Chile and various states in Australia. It was introduced as a fire retardant in the USA and for its erosion control properties in Australia. This study will investigate aspects of the ecology and management of G. pubescens in western regional Victoria. The project aims to provide management solutions which enhance the competitiveness of native grasslands species.
Title: Investigating the physical distribution of arsenic in mining wastes as a function of particle size and the implications for human exposure.
Summary: One of the factors governing the fractionation of arsenic in mining wastes is particle size. The objective of this research is to systematically examine the distribution of arsenic, and other potentially toxic elements, in particles that are considered relevant to mobility (i.e. dust particles) and human exposure (i.e. ingestible and inhalable particles). The analysis presented in this study may be used for guiding strategies for future site management and remediation in settings with similar characteristics.
Shakir Bahaddin Shakir
Title: Investigating factors affecting restoration of native grassland in ex-cropland.
Summary: The ecological barriers to restoring ex-arable land to native grassland include soils that contain high levels of nitrogen and phosphorus, and an extensive seed bank of exotic weeds. These factors give exotic species a competitive advantage over native species, which can prevent the reintroduction of native species. In order to address this situation, we have established a replicated field experiment in former crop land near Werribee, Victoria, to test some novel methods for grassland restoration. This work includes the determination of the individual effects of high N and P levels, and the role of the exotic soil stored seed bank as barriers to restoration. Results will improve our understanding of these barriers to grassland restoration, and provide a stronger theoretical framework for further research.
Title: Detection and prevention of the dispersal of the seeds of Chilean needle grass (Nassella neesiana Trin. & Rupr (Barkworth)) in hay bales.
Summary: It has been established that hay bales may be a significant vector for the dispersal of weeds. Besides the everyday requirements of the livestock industry, bales sent to graziers affected by drought, floods, and fire may also risk the dispersal of weeds. My work has investigated the application of non-destructive core sampling of bales to detect seeds of N. neesiana. This work will enable the use of a rapid, inexpensive method to enforce biosecurity on baled fodder. I have also investigated the use of silage fodder preservation to reduce infestations of this weed in grazed pastures.