The Ocean and Us

Catherine Lovelock, The University of Queensland Conserving and restoringmangrove forests is vital for achiev- ing the SDGs throughout the coastal regions of the tropics be- cause of the wide range of ecosystem services they provide. There are a range of challenges in achieving conservation and restoration of mangrove forests – some technical, many are social and economic – but all of the challenges will be exacerbated by sea level rise, which needs to be incorporated into conservation and restoration planning for the SDGs. Sea level rise poses a serious threat to mangrove forests because although mangrove trees grow in the intertidal and are in- undated at high tides, they have a limited capacity to survive prolonged inundation and recruitment of seedlings is limited when water gets too deep too often. The negative effects of sea level rise on mangrove forests are not only associated

with rising water levels but also dependent on subsiding land. The land in many of the world’s largest deltas, where man- groves support millions of people, is sinking relative to sea level because of the extraction of oil, gas and groundwater and because sediment delivery to the coasts, which enriches mangrove forests adding to their elevation, has been limited by hydrological modification upstream as rivers are dammed, water used for irrigation and sediments mined. Degradation of mangrove forests also increases rates of land subsidence and their vulnerability to sea level rise. To meet the SDGs, the attention of a wide range of natural resource managers, from those that directly manage mangrove forests to those that manage extraction of underground and sediment resources and river flows must be engaged to facilitate favourable con- ditions for mangrove growth. This in turn will limit coastal erosion, which supports SDGs.