Potential climate change impacts on the mangroves and saltmarshes of the Sydney region

Mangroves and saltmarshes are sentinel species in their response to climate change, being sensitive to changes in temperature, sea-level, rainfall and atmospheric CO2. Over recent decades widespread encroachment of saltmarsh by mangrove has been observed in most estuaries, a trend consistent with higher relative sea-levels and temperatures. We used climate change projections, including the outputs of down-scaled regionally-specific climate models to project changes in mangrove and saltmarsh vegetation in the Sydney region over the coming century. Temperature changes are likely to promote an increase in the diversity of mangroves capable of colonising estuaries in the Sydney region, and a decrease in the diversity of saltmarsh, which is strongly associated with cold temperatures. The capacity of mangrove and saltmarsh to respond to sea-level rise through landward encroachment will be constrained by topography in some estuaries (Port Hacking, Hawkesbury) and development in others (Georges River, Parramatta River).