Salvaging and replanting 300 mangrove trees and saplings in the arid Arabian Gulf

Abstract

Construction works along a causeway at Mubarraz Island near Abu Dhabi, United Arab Emirates, in the Arabian Gulf necessitated the salvaging and replanting of 300 mangroves (Avicennia marina). Mangroves were excavated manually by shovel (smaller trees and saplings) or mechanically using a backhoe excavator (larger trees), transported with the root ball wrapped in burlap and replanted in a newly created tidal channel. Relocated mangroves were exposed to two different watering regimes and two tidal inundation levels, and were monitored for survival, plant height and leaf health (percentage of green leaves) at 0 and 1 weeks, and then at 3, 7 and 12.5 months. Tree mortality was high in the first week (24%) in mid-summer, with further losses (43%) during the next 3 months. After 12.5 months, 31% of the transplanted trees had survived. There was a significant effect of the duration of tidal inundation on survival and leaf health (higher survival in shallow than deeper plots). There were no significant effects of initial tree height or freshwater treatment on survival or plant performance. These results demonstrate that salvaging of larger mangroves is technically feasible, potentially providing faster ecosystem services (e.g. shoreline protection, source of new propagules) than newly planted seedlings in arid regions where growth is extremely slow.