Restoration or degradation
: exotic grass management and ecosystem dynamics in Australia's tropical savannas

  • Kristine Johanne Brooks

    Student thesis: Doctor of Philosophy (PhD) - CDU


    Introduced grasses have been associated with the transformation of ecosystem structure and function in the tropical savanna woodlands of Australia and South America. Consequently, there has been considerable research on the process and impacts of exotic grass invasion. However, little attention has been paid to the management of these grasses and how it affects the successional trajectory of savanna systems. Management of invasive species can have unexpected outcomes due to invasion induced changes to the system and through the impacts of the management action itself. Removal of the invasive species can be a large biotic change that, if poorly considered, could be responsible for creating positive feedbacks that promote further degradation. Consequently, methods used to remove invasive species have the potential to cause biotic and abiotic degradation, even when the invasion process itself may not.

    In Australia's tropical savannas, Andropogon gayanus Kunth. (gamba grass) and Pennisetum polystachion L. Schult. (perennial mission grass) are increasingly the focus of intensive management programs. This is motivated by the rapid spread of both exotic grasses into a range of habitats in disturbed and undisturbed savanna and their potential to alter fire regimes and nutrient cycling. However, empirical information on the effects of widely accepted exotic grass management techniques on the tropical savannas of north Australia has not been documented. Therefore, this thesis focuses on an important aspect of invasive species management in the savannas the impact of exotic grasses and their management on the potential for restoration in the savanna woodland.
    Date of Award2010
    Original languageEnglish
    SupervisorSamantha Setterfield (Supervisor) & Michael Douglas (Supervisor)

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