School of Ecosystem and Forest Sciences - Theses

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    Larger tuber size improves Microseris walteri (Murnong; Yam Daisy) transplant success
    Roberts, Eilish ( 2021)
    Since European settlement, the vast majority of Natural Temperate Grassland in south-eastern Australia has been destroyed or drastically altered. Microseris walteri, also known as Yam Daisy or Murnong, is one of many grassland species that has experienced considerable losses. M. walteri is known for its small, sweet-tasting tubers that were once a staple food source for many First Nations people. Successfully reintroducing Murnong populations into grasslands has proven very difficult. Here we investigated whether tuber size impacts translocation success. Microseris walteri plants with larger tubers (4.5 - 14.2 g) had significantly higher survival rates relative to medium (2.1 - 3.4 g) and small tubers (0.4 - 1.6 g). Additionally, tuber size was found to be positively correlated with the plants’ total leaf number, as well as the length of the longest leaf. Reintroduction by sowing seed was found to be ineffective. Together these results indicate that future Yam Daisy reintroductions should focus on transplanting plants with a greater tuber mass for a better chance of reintroduction success. Future research is required to better understand how to influence plants to grow larger Murnong tubers in a production system.
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    Effects of vegetation structure, fire and habitat amount on microbat functional diversity
    Button, Amber Elizabeth ( 2020)
    Human modification of land cover and disturbance regimes is occurring at unprecedented rates globally, and often results in significant biodiversity loss. However, it is often unclear how the loss of species affects ecosystem function. The relationship between ecosystem function and biodiversity depends on the functional traits and niches filled by organisms, as these traits respond to and drive ecosystem processes. Functional diversity describes the range, value and distribution of traits and is a better predictor of ecosystem function than species richness. This study investigated the effects of vegetation structure, fire and habitat amount on microbat functional diversity. Using passive acoustic monitoring, we surveyed microbats at 140 sites over two years. Four bat functional traits were used to calculate four functional diversity indices (richness, evenness, divergence and dispersion). The influence of vegetation structural complexity, time since fire and habitat amount on bat functional diversity and species richness was examined using generalised linear models. With the exception of one measure of functional diversity, time since fire did not influence any of the response variables. In contrast, vegetation structural complexity was a much stronger predictor of functional diversity than time since fire, with functional diversity increased in more structurally open environments. Both functional evenness and functional dispersion of bats were both positively associated with habitat amount, indicating that increased habitat amount results in reduced environmental filtering and an increased breadth of functional roles performed by the bat community. Finally, FD responses often depended on the survey year, indicating that responses were influenced by temporal variability in background conditions. These findings suggest that management for biodiversity should be focused on optimising vegetation structure through the use of fire, rather than focusing on fire regime alone. Further, management actions that protect and increase habitat amount should, therefore, increase overall bat functional diversity arising from the increased abundance of foraging and roosting resources available. Lastly, long-term monitoring programs measure species responses across a variety of conditions, thereby providing more representative evidence to develop well informed management decisions.