B.Sc. (Wildlife and Conservation Biology)
A thesis submitted in total fulfilment of the requirements for the degree of Master of Science by Research
The introduction and establishment of non-native species into novel ecosystems can cause significant ecological and economic harm. Native to the tropical environments of India, southern China and south-eastern Asia, sambar deer (Rusa unicolor) have become well established following their introductions into Australia in the late nineteenth century. Land managers, community groups and researchers are increasingly concerned by the presence of these large-bodied ungulates across a variety of contrasting habitats in the state of Victoria, and their impacts on biodiversity.
The aim of this thesis was to investigate the impacts of sambar deer through browsing and seed-dispersal in native alpine and wet forest ecosystems of south-eastern Australia. A variety of methods were utilised to understand sambar deer dietary impacts, the results of which will provide land managers with information on the plant species and communities most vulnerable to sambar deer presence.
I examine both the feeding and dispersal impacts of sambar deer on plant species in two contrasting environments: the wet forests of the Yarra Ranges National Park, and the high-elevation communities of the Alpine National Park. This was achieved through the collection of faecal pellet samples, which were analysed using DNA metabarcoding techniques to detail the full dietary profile and subjected to one year of glasshouse germination trials to examine the potential for species to be spread. The results of this chapter revealed contrasting patterns, where a large proportion of the species detected in the sambar deer diet were of native origin, yet a higher number of exotic seedlings were observed during germination trials. I discuss the implications of these findings for native ecosystems inhabited by sambar deer. I further investigated spatial and temporal variation in the diet of sambar deer in the Alpine National Park over a three-month flowering period. The results of this study show that sambar deer diet is dominated by forb species in the Alpine National Park, which are the most abundant plant growth form in the landscape and highlight a feeding behaviour driven by forage availability. Most interestingly, spatial variation in the diet was evident over relatively small scales. This suggests that the management of sambar deer in the Alpine National Park requires site-specific approaches, as the varying composition of plant species within sites may result in very different impacts exerted by sambar deer.