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Invasive species pose a major threat to Australia's biodiversity and agriculture. For example,

Invasion species reseach at UNSW focus on five key questions associated with each phase of the alien invasion, and we are addressing these questions in marine and terrestrial ecosystems.

 

(supervisor Emma Johnston)

 

Richard Piola (PhD 2005-) The discharge of toxicants into coastal waters is an increasingly important source of disturbance that has the potential to make marine assemblages more susceptible to biotic invasion. We ask if pollution events facilitate the colonisation, persistence and spread of non-native species. The metal-tolerance of indigenous and non-indigenous sessile marine invertebrates has been compared and the ecological consequences of differential tolerance examined in the field.

 

Katherine Dafforn (PhD 2005-) Estuaries are among the most highly disturbed of all coastal habitats. Examples of anthropogenic disturbances include pollution from surrounding industrial and urban areas, modification of marine habitat, and the introduction of non-indigenous species via shipping. Our study will use a series of field surveys and experiments in various NSW estuaries to investigate the direct and indirect effects of shipping on marine invasion. We will investigate whether commercial and recreational vessels are associated with the transport of different levels and types of invaders. We will also consider whether pilings and pontoons introduced to accommodate vessels may be facilitating the establishment of non-indigenous species in new regions. Finally, we will investigate the dispersal of non-indigenous species from these artificial structures into natural rocky reef habitats, with the aim of advising future management decisions.

 

 

(supervisor Emma Johnston)

 

Graeme Clark (PhD 2006-) An important goal in ecology is to understand whether species diversity in communities prevents invasion by new species. To tackle this question we have developed a new conceptual model that uses the intermediate disturbance hypothesis to explain invasion patterns. It predicts that diversity and invasibility could be either positively or negatively related in the short-term depending on the successional ages of the communities being invaded. In the long-term however, diversity and invasibility should be positively correlated regardless of successional age. We are testing this model in the field by experimentally manipulating sessile marine invertebrate communities and exposing them to new 'invaders'.

 

 

Louise McKenzie (PhD 2007-) Pollution is a potentially powerful agent of selection acting on aquatic organisms. Evolutionary ecotoxicology is a new research program at UNSW combining quantitative and molecular genetics with field and laboratory-based ecotoxicology. Numerous studies have reported differential toxicant sensitivity between populations of the same species. Our research has identified that pollution tolerance increases the dominance of non-indigenous sessile marine organisms such as the bryozoan Watersipora subtorqata. Quantitative genetics experiments will establish the genetic basis for elevated tolerance.

 

 

(supervisor William Sherwin)

 

Lee Ann Rollins (PhD 2004-): The starling (Sturnus vulgaris) invasion into Australia began in the mid-19^th Century in the east and continues presently on the edge of the range expansion in Western Australia. We are using the genetic signatures of the eastern Australian populations to determine the minimum number of invasions into Western Australia and their origin, whether barriers to migration exist, and whether certain demographic groups are more likely to disperse. This crucial information will be incorporated into future management plans for the control of Western Australian starling populations. Additionally, our research  has identified significant changes to gene frequencies along the invasion front which support theoretical predictions regarding the genetics of small, rapidly expanding populations. Although alien species invasions are a key threatening process to biodiversity, they provide unique opportunities to study 'natural' experiments on scales that might otherwise be impossible and can be used to verify theoretical predictions.

 

 

(supervisor Peter Banks)

 

Terrestrial alien predators have proven to be the worst of all invasive species and their impacts in Australia have been acute and devasating to our unique wildlife. We are examining what factors contribute to such extreme success of alien predators by looking at each stage of the predator:prey encounter

 

Catherine Price  (PhD 2006-): Introduced vertebrate predators, including foxes, dogs, cats and rats, are implicated in the decline and extinction of more than 100 Australian native species. This research aims to gain a better understanding of the behavioural and physiological processes which allows these introduced predators to exploit native prey successfully, with the goal of developing methods to disrupt these processes. The process of olfaction and odour cues are of particular interest, with several previous studies examining the response of prey species to predator odour cues. Future projects will focus on the way in which predators use prey signals, particularly scent cues, to guide foraging activities at relevant temporal and spatial scales, types of prey cues used by predators when foraging and whether predator foraging efficiency can be altered through the manipulation of prey cues in the environment.

 

(Karen Fey  University of Turku, Finland PhD 2004-): Alien predators generally have a greater impact on prey populations that do native predators, but why? This project examines factors which influence the significant impact of feral mink on fragemented island populations of voles in the Baltic Sea Archipelago, Finland. Using a series of manipulative field experiments, we are studying the interplay between top-down and bottom-up processes in vole metapopulation dynamics and the role of prey naivete in determining vulneraibilty of voles to mink impact.

 

 

(supervisor Peter Banks)

 

Nelika Hughes (PhD 2004-) House mice are amongst the worst alien pests in Australia's agricultural environments, causing $100's damage to wheat crops during chronic outbreaks which occur somewhere in Australia every 2 years. The key to the mouse's incredible ability to irrupt seems to lie in their social organization. This project is examining factors that affect olfactory communication in house mice, the means by which social hierarchies are formed and mouse socieity functions. In particular we are looking at how the risk of predation from scent hunting predators such as snakes and cats may disrupt the social network through its impact on receiving and sending social signals. Our experiments will reveal how mice use odour to communicate in field conditions, what the social costs are of not receiving social signals under predation risk, and ultimately will reveal how mice balance the need to communicate with the risks of predation.

 

(Pälvi Salo University of Turku PhD 2005-) Amercian mink pose some of the biggest threats to biodiverity in Europe. In the archipealgo of the Baltic Sea, mink suppress populations of breeding seasbirds, small mammals and frogs. This area is missing it's apex predator, the white-tailed eagle, which declined though the 20th century due to overhunting.  This project examines whether the recent return of the eagle to parts of the archipegalo is having a net benefit to biodiversity by alterting the behaviour and population dynamics of feral mink.