Vegetation resistance and regeneration potential of Rhizophora, Sonneratia and Avicennia in the Typhoon Haiyan-affected mangroves in the Philippines: implications on rehabilitation practices

Typhoons cause damage to mangrove ecosystems, hampering their delivery of ecosystem goods and services, including coastal protection. We examined the vegetation resistance (VR) and regeneration potential (RP) of three mangrove genera: Rhizophora, Sonneratia and Avicennia at the low intertidal zone. This study assessed genus-specific resistance to and recovery from the impacts of Typhoon Haiyan, by far the strongest storm to make landfall in recorded history. VR was estimated using density, tree height and circumference at breast height. RP was measured as the post-disturbance seedling growth rate within a given plot. Thirty six 3m-radii plots were established in the typhoon-affected mangrove areas of Ormoc City and Tacloban City in Leyte; and Quinapondan and General MacArthur in Eastern Samar.  Results showed that Avicennia species yielded the highest average VR at 356, while Rhizophora had the lowest VR at 74. The different genera could also be arranged from highest to lowest RP: Avicennia (67.27 ± 2.62 cm*yr -1 ) > Sonneratia (58.20 ± 12.02 cm*yr -1 ) > Rhizophora (32.46 ± 4.64 cm*yr -1 ) . Overall, our finding on the higher relative VR and RP values of Sonneratia and Avicennia calls for a shift in mangrove planting practices at the low intertidal zones, which currently favor Rhizophora .