John B. Baumgartner (1), Karel Mokany (2), David A. Nipperess (3), Linda J. Beaumont (4)

1 Department of Biological Sciences, Macquarie University, NSW, 2109, john.baumgartner@mq.edu.au, @johnbaums

2 CSIRO Land & Water Flagship, Canberra, ACT, 2601, karel.mokany@csiro.au

3 Department of Biological Sciences, Macquarie University, NSW, 2109, david.nipperess@mq.edu.au

4 Department of Biological Sciences, Macquarie University, NSW, 2109, linda.beaumont@mq.edu.au, @Beaumontlj

Inference about community-scale dynamics based on suites of single-species models is limited because key factors influencing community assembly and composition are typically ignored (e.g. dispersal and assembly processes, patterns of co-occurrence, and the response of these to environmental gradients). Accordingly, focus is shifting towards models of co-occurrence and community composition that explicitly incorporate these processes. These models are particularly valuable in informing optimal regional allocation of management resources aimed at protecting large numbers of species. For much of Australia the outlook for general patterns of biodiversity in the face of climate change is unclear. To better understand the community-scale impacts of climate change on NSW native flora, we used occurrence data for 6000 native plant species to model patterns of richness and spatial turnover in community composition. These models were then used as a basis for predicting temporal dynamics in future composition, through simulation of dispersal and community assembly under climate change. Our models propagate uncertainty in future climate by assessing outcomes under four possible, but contrasting, future climate scenarios using regional climate projections for NSW. Our analysis revealed areas likely to retain high species richness through time, serving as refugia for communities, as well as those that might harbour threatened taxa in the face of climate change. This understanding will improve our ability to adapt to climate change by informing strategic allocation of resources to the protection of ecological communities across NSW.