Temperate ecosystems worldwide are approaching tipping-points as cumulative environmental impacts threaten the processes determining habitat quality and biodiversity. One such accelerating impact is ocean warming, facilitating species movement into previously unsuitable regions, resulting in catastrophic shifts in ecosystem composition. In southeast Australia, the longspined sea urchin, Centrostephanus rodgersii, has undergone a poleward range extension from native New South Wales to the cooler Tasmanian waters, simplifying rocky reef habitats to ‘barrens’ habitat. This shift has ultimately devastated kelp ecosystems, threatening the viability of commercial fisheries and recreational industries. While many studies have documented species undergoing climate-driven range extension and investigated the potential processes facilitating their expansion, comparatively fewer have evaluated whether these underlying drivers can reproduce empirical observations. This presentation highlights the use of a spatially explicit mechanistic model in recreating the historical range extension of Centrostephanus rodgersii, across southeastern Australia. Using this model, we identify key processes influencing mature densities across broad spatial scales and predict future distributions under alternative climate warming scenarios. Together, these findings pose an interesting question: does continued climate warming simply drive ongoing range extensions, or do range contractions ultimately follow?