Identifying climate refugia for 30 Australian rainforest plant species, from the last glacial maximum to 2070

Abstract

Climate refugia—areas that remain suitable for species during periods of climate disruption—have played an important role in species persistence over time. Identifying and protecting these refugia is a key climate change adaptation approach for conservation planning. To identify climate refugia for Australian tropical/sub-tropical rainforest flora, from the Last Glacial Maximum to 2070. Habitat suitability models were calibrated for 30 species using Maxent, and projected onto climate data for: Last Glacial Maximum (LGM, ~ 22,000 ybp); mid-Holocene (MH, ~ 6000 ybp); current period; and 2070. The intersection of suitable habitat over consecutive periods was assessed, identifying: current refugia (LGM–MH–Current); future refugia (Current–Future); and High Value Refugia (HVR, suitable over all four periods). Refugial hotspots (regions suitable for at least 15 species) were also identified. Suitable habitat was generally projected to span the greatest area in the current period. Four current refugial hotspots were identified: Wet Tropics, Central Mackay Coast, South Eastern Queensland, and North Coast (New South Wales). While suitable habitat for most species may decline in the future, HVRs will likely be retained for all species to at least 2070, although restricted in size. Future refugia was also projected in areas beyond species’ dispersal ranges. HVRs are highly important for the conservation of these rainforest species, given their generation times, limited dispersal capabilities and additional anthropogenic barriers to movement. This study assists in understanding long-term spatial shifts in rainforest flora in response to climate change and in designing future conservation strategies.