My talk will be structured into three sections, as follows:

(1) Predicting and managing the ecological impacts of marine species on the move using qualitative network models Worldwide, a large proportion of species are undergoing sustained climate-driven changes in their distributions. The ecological, social and economic consequences of these range-shifts on regional ecosystems can be large and hard to reverse, but remain challenging to predict and pro-actively manage. Based on qualitative knowledge about regional ecosystem structure and range-shifting species, our generic framework can help identify in dividual range-shifting species, or groups of species, that can have widespread detrimental effects on ecosystem structure and productivity. Using temperate reef systems in southeastern Australia as a case study, our finding s suggest that the negative impacts of simultaneous range-shifts are synergistic, and hence, can only be effectively mitigated by ecosystem-based management strategies that combine multiple management interventions.

(2) Simulation modelling & ecosystem-based management of the Tasmanian rock lobster fishery Following rapid climate-driven changes in ocean currents, the long-

spined sea urchin (Centrostephanus rodgersii) has extended its range from Australia’s mainland to eastern Tasmania. Due to the depletion by fishing of large rock lobster (Jasus edwardsii), its main predator on Tasmanian reef, C. rodgersii has demonstrated the ability to form and maintain extensive ‘barrens’, i.e. bare rocks following the destructive grazing of macroalgal cover. Relative to dense seaweed beds, sea urchin ‘barrens’ represent a dramatic loss of habitat, biodiversity and productivity for important commercial reef species such a southern rock lobster (Jasus edwardsii) and abalone (Haliotis rubra). TheTRITON model, specifically developped to realistically captures seaweed bed-seaurchin-rock lobster community dynamics, provide ecosystem-based guidance for the regional management of rocky reef communities.In particular, simulations help define effective interventions and a safe operating space, which recognises the central role of rock lobster to reef dynamics, so as to prevent phase shifts in reef dynamics from (i) dense, species-rich, productive seaweed beds to (ii) impoverished and widespread sea urchin ‘barrens’.